JP3672557B2 - Nodes and hierarchical networks - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a configuration technique of a path network that performs traffic engineering such as path selection and rearrangement of paths.
[0002]
[Prior art]
When networks of a plurality of layers coexist, individual network management is often performed in each layer. At this time, the network management method differs depending on the layer, and a single device grasps the state of the entire network, and a centralized control method in which control is performed, and all nodes in the network share information by exchanging link states. There are distributed control methods.
[0003]
In addition, there is a method in which a network is divided into a plurality of areas and managed in each area only for control of one layer. (For example, see Non-Patent Documents 1 and 2)
[0004]
[Non-Patent Document 1]
K. Sato, N. Yamanaka, et al., "GMPLS-based photonic multilayer router (Hikari router) architecture: an overview of traffic engineering and signaling technology," IEEE
Commun. Mag., Vol. 40, Issue 3, Mar. 2002
[Non-Patent Document 2]
E. oki, N. Yamanaka, et al., "A heuristic multi-layer optimum topology design scheme based on traffic measurement for IP + phatonic networks," Optical Fiber Communication Conference and Exhibit, pp. 17-22, Mar. 2002
[0005]
[Problems to be solved by the invention]
When performing distributed control multi-layer traffic engineering in a situation where multiple layers of networks coexist, traffic engineering has been conventionally performed for the entire network, so routing protocols such as OSPF (Open Shortest Path First) are collectively used. Since the amount of information handled increases and the amount of traffic engineering calculations becomes enormous, it is difficult to realize expansion to a large-scale network.
[0006]
This problem will be described more specifically. An example of a network composed of a plurality of layers of networks is shown in FIG. Here, it is assumed that it is composed of an IP layer, an SDH layer, and a wavelength layer. In this network, each node advertises a link state composed of information such as an IP address, a maximum bandwidth of the link, and a used bandwidth.
[0007]
Based on this link state, the node that sets the path determines whether to set a new SDH path or wavelength path in order to set an IP path. The path is set by calculating whether the cost is the smallest when setting is set. Further, when rearranging a route of a certain IP path, the necessity of changing the route of the wavelength path of the lower layer is calculated at the same time. In such a network, the processing load such as the link state advertisement amount and the route calculation amount increases as the network size increases, so that scalability cannot be maintained at a certain scale. The same can be said for the increase in the number of layers handled in a lump.
[0008]
The present invention has been made in this background, and can be extended to a large-scale network even in a network that requires complicated processing such as a multi-layer network. Since calculation can be performed after specifying a range that requires route calculation, invalid calculations can be eliminated, and a node, a hierarchical network, a network control device, and a hierarchy that can efficiently perform route calculation An object of the present invention is to provide a method for configuring a network.
[0009]
[Means for Solving the Problems]
The present invention introduces the concept of a virtual node described below for a network in which processing load such as link state advertisement amount and route calculation amount is enormous when the entire network is handled collectively, This virtual node is hierarchized, and processing is distributed among the virtual nodes, whereby the processing load of the entire network can be distributed.
[0010]
As a result, even a network that has a huge processing load on the entire network can be scaled up. In addition, since the calculation can be performed after the range requiring the route calculation is specified, invalid calculations can be eliminated, and the route calculation can be performed efficiently.
[0011]
That is, according to the first aspect of the present invention, nodes constituting a network are divided into cells each composed of one or a plurality of nodes, and these cells are defined as level 1 virtual nodes. Constitutes a level 1 virtual network, and the level 1 virtual nodes constituting the level 1 virtual network are further divided into cells composed of one or more virtual nodes to form level 2 virtual nodes. A hierarchical network is configured by virtual networks of 1 to N levels constructed by performing such cell division and virtual node operation once or a plurality of N times. In the hierarchical network, If there is a link connecting different virtual nodes at different levels, the virtual node on this link A node corresponding to a contact point between the unit and the outside is defined as an interface, and when the highest virtual node related to the interface is level M (≦ N), the interface is a multi-level interface from levels 1 to M Are nodes constituting a level 1 virtual node in a hierarchical network defined to also serve as a node that does not correspond to the interface.
[0012]
A technique for automatically configuring such a hierarchical network has already been proposed in Japanese Patent Application No. 2002-293679 (not disclosed at the time of filing this application).
[0013]
Here, the feature of the present invention is that the link information connected to the other nodes in the own virtual node and the link cost information of the link are advertised from the other nodes in the own virtual node. Means for receiving advertisement of link information and link cost information of the link in the own virtual node and holding the information, a node corresponding to the interface of the own virtual node from a node corresponding to the interface, and a virtual of level 2 or higher And a means for receiving an advertisement of link information with a node corresponding to the interface of the node and link cost information of the link and holding the information.
[0014]
As a result, each node can hold link information and link cost information in its own virtual node and link information and link cost information between border nodes of other virtual nodes, and performs route calculation based on these information. be able to.
[0015]
Means for transmitting own IP address to a node corresponding to the interface of the own virtual node, IP addresses of other nodes belonging to virtual nodes other than the own virtual node transmitted from the node corresponding to the interface, and the corresponding IP address It is desirable to have means for holding external IP address group information that is information of the virtual node. As a result, each node can know the location of the node to which it is addressed.
[0016]
A means for transmitting the own IP address to a node corresponding to the interface of the own virtual node, an IP address of another node belonging to a virtual node other than the own virtual node, and an external IP address group which is information of the virtual node to which the IP address belongs Means for requesting and obtaining information from a node corresponding to the interface.
[0017]
Thereby, each node can receive provision of IP address group information from a node corresponding to an interface as needed without holding IP address group information. Therefore, the data amount of the node can be reduced.
[0018]
Means for transmitting own IP address and link cost information between the node corresponding to the interface of itself and the own virtual node to the node corresponding to the interface, and the own virtual node transmitted from the node corresponding to the interface IP address of other nodes belonging to other virtual nodes, external IP address group information which is information of virtual nodes to which the IP addresses belong, and link cost information from the node corresponding to the interface to the other nodes It is also possible to provide means for holding corresponding to the address. Thereby, each node can know the location of the destination node and the link cost to the node.
[0019]
Means for transmitting the own IP address and link cost information between the node corresponding to the interface of the self and the virtual node to the node corresponding to the interface, and the IP of another node belonging to a virtual node other than the virtual node External IP address group information, which is information on the virtual node to which the address and the IP address belong, and link cost information from the node corresponding to the interface to the other node correspond to the interface by designating the IP address of the other node And means for requesting and acquiring the node.
[0020]
Thereby, each node can receive the IP address group information and the link cost information from the node corresponding to the interface as needed without holding the IP address group information and the link cost information. Therefore, the data amount of the node can be reduced.
[0021]
It is desirable to provide means for sending a reachability confirmation packet to a node corresponding to the interface of the own virtual node. Thereby, the node corresponding to the interface can obtain reachability information regarding other nodes.
[0022]
Means for calculating link costs for nodes corresponding to the plurality of interfaces of the own virtual node, and the means for sending is assigned to the node corresponding to the interface having the lowest link cost according to the calculation result of the means for calculating; On the other hand, a means for transmitting a reachability confirmation packet may be provided. Thereby, the node corresponding to the interface can obtain the reachability information regarding the other node having the lowest link cost.
[0023]
Means for calculating link costs for the nodes corresponding to the plurality of interfaces of the own virtual node, and the sending means is nth (n is a natural number) in ascending order of link cost according to the calculation result of the means for calculating. It is also possible to provide means for transmitting a reachability confirmation packet to a node corresponding to the above interface. As a result, the node corresponding to the interface can obtain reachability information regarding other nodes having a link cost as low as nth.
[0024]
Means for calculating link costs for the nodes corresponding to the plurality of interfaces of the own virtual node, and the sending means is nth (n is a natural number) in ascending order of link cost according to the calculation result of the means for calculating. It is also possible to provide means for transmitting a reachability confirmation packet including the order information to the nodes corresponding to the above interfaces.
[0025]
As a result, the node corresponding to the interface can obtain information indicating the reachability and link cost of other nodes having a link cost as small as the nth link. The reference information can be realized with a very small amount of data compared to the link cost information as it is.
[0026]
Or means for advertising link information connected to itself to other nodes in the own virtual node and link cost information of the link; link information in the own virtual node from other nodes in the own virtual node; and And means for receiving an advertisement of link cost information of the link and holding the information.
[0027]
According to this, the information held by the node is limited to the information in the own virtual node. Therefore, the data amount of the node can be reduced. However, a route calculation extending to another virtual node is impossible only with information in the own virtual node.
[0028]
Therefore, prior to the route calculation, the node corresponding to the link information between the node corresponding to the interface of the own virtual node and the node corresponding to the interface of the virtual node of level 2 or higher and the link cost information of the link It is desirable to provide a means for requesting and obtaining the data.
[0029]
According to this, since information can be acquired from a node corresponding to an interface as required for route calculation, the node can hold a necessary minimum amount of data.
[0030]
A second aspect of the present invention is a node corresponding to the interface, and the feature of the present invention is that link information in the own virtual node connected to the other node in the own virtual node. And link cost information of the link and a link information between nodes corresponding to interfaces of other virtual nodes connected to the link and link cost information of the link, and means from other nodes in the virtual node A link between the node corresponding to the higher-level interface from the node corresponding to the interface of the other virtual node and the means for receiving the advertisement of the link information in the own virtual node and the link cost information of the link and holding the information Means for receiving advertisements of information and link cost information of the link and holding the information There is the time.
[0031]
In this way, the node corresponding to the interface makes an advertisement to other nodes in the own virtual node, so that the node can obtain link information and link cost information.
[0032]
Means for collecting and holding IP address information from other nodes in the own virtual node, means for advertising the IP address information collected by the means for collecting and holding to a node corresponding to the interface of the other virtual node, and others The own virtual node which holds the IP address of other nodes belonging to the virtual node other than the own virtual node advertised from the node corresponding to the interface of the virtual node and the external IP address group information which is information of the virtual node to which the IP address belongs It is desirable to provide a means for transmitting to other nodes in the system.
[0033]
In this way, the node corresponding to the interface makes an advertisement to other nodes in the own virtual node, so that the node can obtain reachability information.
[0034]
Means for collecting and holding IP address information from other nodes in the own virtual node, means for advertising the IP address information collected by the means for collecting and holding to a node corresponding to the interface of the other virtual node, and others Means for holding an IP address of another node belonging to a virtual node other than its own virtual node advertised from a node corresponding to the interface of the virtual node, and external IP address group information which is information of the virtual node to which the IP address belongs; It is also possible to provide means for providing the external node with the external IP address group information held in the holding means in response to a request from the node.
[0035]
As described above, since the node corresponding to the interface provides the external address group information in response to a request from the other node, the other node can acquire the external address group information as necessary. Other nodes may hold the minimum necessary information.
[0036]
Means for collecting and holding IP address information and link cost information between the other node and itself from other nodes in the own virtual node, and IP address information and link cost collected by the means for collecting and holding A means for advertising information to a node corresponding to an interface of another virtual node, an IP address of another node belonging to a virtual node other than the own virtual node advertised from a node corresponding to the interface of the other virtual node, and the IP address The external IP address group information, which is virtual node information, and the link cost information from the node corresponding to the interface of the other virtual node to the other node are held corresponding to the IP address of the other node and stored in the own virtual node And means for transmitting to other nodes.
[0037]
In this way, the node corresponding to the interface transmits the external address group information and the link cost information to the other nodes in the own virtual node, so that the node can obtain the external address group information and the link cost information.
[0038]
Means for collecting and holding IP address information and link cost information between the other node and itself from other nodes in the own virtual node, and IP address information and link cost collected by the means for collecting and holding A means for advertising information to a node corresponding to an interface of another virtual node, an IP address of another node belonging to a virtual node other than the own virtual node advertised from a node corresponding to the interface of the other virtual node, and the IP address Means for holding external IP address group information, which is virtual node information, and link cost information from a node corresponding to the interface of the other virtual node to the other node, corresponding to the IP address of the other node; External IP address group information held in the holding means in response to a request from And link cost information may also be provided with means for providing to the another node.
[0039]
In this way, the node corresponding to the interface provides the external address group information and the link cost information in response to a request from another node, so that the other node can send the external address group information and the link cost information as necessary. And the other node only needs to hold the minimum necessary data amount.
[0040]
A means for receiving reachability confirmation packets from other nodes in the own virtual node and aggregating the IP addresses of the packets received by the receiving means to generate internal IP address group information relating to the nodes in the own virtual node The internal IP address group information generated by the generating means is exchanged between the means for generating and another node corresponding to the interface in the own virtual node, and the excess or deficiency is corrected to make the unified internal in the own virtual node A means for synchronizing as IP address group information and a means for advertising internal IP address group information unified by the synchronizing means to a node corresponding to an interface of another virtual node may be provided.
[0041]
According to this, since a node corresponding to a plurality of interfaces advertises the same internal IP address group information to other virtual nodes, the reliability of information can be improved.
[0042]
The advertising means includes means for determining the presence / absence of an advertisement path from another node corresponding to the interface in the own virtual node to a node corresponding to the interface of the same other virtual node, and the determination result of the determining means is “ When it is “Yes”, it is possible to provide a means for advertising to a node corresponding to the interface of the other virtual node through one of the advertisement paths of the node or the other node. According to this, it is possible to effectively use resources without performing extra advertisements.
[0043]
A means for receiving reachability confirmation packets from other nodes in the own virtual node and aggregating the IP addresses of the packets received by the receiving means to generate internal IP address group information relating to the nodes in the own virtual node And means for advertising the internal IP address group information generated by the generating means to a node corresponding to an interface of another virtual node.
[0044]
According to this, when the internal IP address group information between different nodes corresponding to the interface in the same virtual node is different, by allowing it, even if it is the same virtual node, depending on the different node corresponding to the interface Since it is possible to know from the advertisement that the reachability is different, it is possible to obtain information useful for route calculation.
[0045]
Means for receiving a reachability confirmation packet including information indicating that the link cost is nth lowest for the other node from the other node in the own virtual node, and the IP address of the packet received by the receiving means For each of the n values to generate internal IP address group information relating to a node in the own virtual node, and the internal IP address group information generated by the generating means corresponds to an interface of another virtual node. And means for advertising to the node.
[0046]
According to this, the reachability information can be classified according to the link cost class, and it is possible to obtain information useful for route calculation, though roughly. Moreover, since it is rough, there exists an advantage which can reduce data amount.
[0047]
Alternatively, a means for advertising link information of the same level as the self and link cost information of the link connected to the node corresponding to the interface corresponding to the same level as the self, and a node corresponding to the interface corresponding to the same level as the self It is also possible to provide means for receiving an advertisement of link information between nodes corresponding to an interface at the same level as the self and link cost information of the link and retaining the information.
[0048]
According to this, an advertisement is performed only between nodes corresponding to the same level interface as the self, and information held is only information between nodes corresponding to the same level interface as the self. Thereby, it is possible to reduce the advertisement amount and data retention amount of the node corresponding to the interface. However, if only information between nodes corresponding to the same level interface as that of itself is known, it is impossible to calculate a route extending to a higher level.
[0049]
Therefore, prior to route calculation, it is provided with means for requesting and obtaining link information with a node corresponding to an interface at a higher level than itself and link cost information of the link from the node corresponding to the interface. desirable.
[0050]
Although the hierarchical network including the nodes as described above, in the route search of the nodes in such a hierarchical network, for example, the source node in the route setting is the destination node in the route setting based on the external IP address group information Means for identifying the virtual node to which the destination node belongs from the IP address of the node, link information between the node corresponding to the interface of the own virtual node and the node corresponding to the interface of the virtual node of level 2 or higher, and the link of the link Means for searching for a route to a node corresponding to the interface of the virtual node to which the destination node specified by the specifying means based on the cost information belongs.
[0051]
As a result, the source node can search for a route to the node corresponding to the interface of the virtual node to which the destination node belongs for the time being. In this case, the route from the node corresponding to the interface to the destination node may be left to the node corresponding to the interface.
[0052]
Alternatively, it is obtained by means for requesting and obtaining link information in the virtual node and link cost information of the link from a node corresponding to the interface of the virtual node to which the destination node belongs, and means for obtaining and requesting the link In addition to the route searched for by the means for searching for the route to the node corresponding to the interface of the virtual node to which the destination node belongs based on the link information and the link cost information of the link, the node corresponding to the interface Means for searching for a route to the node may be provided.
[0053]
According to this, since the route in the virtual node to which the destination node belongs can also be searched on the source node side, all the routes can be made the routes desired by the source node.
[0054]
Or means for requesting and obtaining link information in the virtual node and link cost information of the link from a node corresponding to the interface of the virtual node included in the path from the self to the destination node; It is also possible to provide means for searching for a route in the virtual node included in the route from the self to the destination node based on the link information obtained by the obtaining means and the link cost information of the link.
[0055]
According to this, the source node can search in detail all routes from the source node to the destination node, and fine routes can be set at the source node.
[0056]
Alternatively, the source node in the route setting is a means for specifying the virtual node to which the destination node belongs from the IP address of the destination node in the route setting based on the external IP address group information, and the node corresponding to the interface of the own virtual node and the level 2 Which level is the top-level virtual node that can calculate the route from itself to the node corresponding to the interface based on the link information with the node corresponding to the interface of the virtual node and the link cost information of the link Information indicating whether or not there is a means for notifying the destination node in the route setting of a result of searching for the top n-th route in ascending order of link cost from the self to the node corresponding to the interface, Based on the received information, the interface from the source node A result of searching for a route from itself to a node corresponding to the interface of the highest-level virtual node capable of calculating a route to a node corresponding to a node, and searching for a route to the upper n-th in the search result And a means for notifying the originating node of the route having the lowest link cost as the finally searched route.
[0057]
According to this, the destination node is the subject of route calculation rather than the source node. For example, when it is necessary to calculate routes from one source node to many destination nodes, if the source node performs a large number of route calculations at once, the processing load on the source node becomes enormous. If this method is applied to such a case, the processing load on the originating node can be reduced by distributing the processing load to a large number of destination nodes.
[0058]
Further, a means for determining whether or not a link connecting the own virtual node and another virtual node is connected to itself by referring to the link information held in the holding means, and a determination result of the determining means And means for determining whether or not the link connecting the own virtual node and another virtual node is connected to itself, whether or not the host is equivalent to the termination point in the layer of the path set to the link It is desirable to provide means for recognizing that the node is a node corresponding to the interface when the device corresponds to the termination point based on the determination result of the device and activating a function corresponding to the interface.
[0059]
That is, the network to which the present invention is applied is a multi-layer network. In a multilayer network, for example, a plurality of layers such as a wavelength path in the Lambda layer, an SDH path in the SDH layer, and a VP (Virtual Path) in the IP layer are mixed. Each node includes nodes having various functions such as those having a wavelength switching function, those having a packet switching function, or those having both. When the hierarchical network of the present invention is applied to such a multi-layer network, the wavelength path, the SDH path, and the VP are mixed as paths connecting the virtual nodes.
[0060]
In a virtual node in such an environment, when a node having a function of terminating a path between virtual nodes terminates the path in the layer of the path, the node is set as a node corresponding to an interface. Therefore, if the path is a wavelength path, an optical cross-connect device or the like having a wavelength switching function can be a node corresponding to an interface. If the path is VP, a router having a packet switching function can be a node corresponding to an interface.
[0061]
In addition, when the resource usage status related to itself and the resource used for data transfer to other nodes in the own virtual node are not available based on the monitoring result of the monitoring means and the self corresponds to the interface A means for invoking a function as a node belonging to another virtual node of level 1 connected to the self, and updating virtual node information to which the self belongs according to a change of the virtual node to which it belongs, and update contents of the means for updating It is desirable to provide means for advertising and means for updating the virtual node information to which it belongs when receiving the advertisement from another node based on the advertisement.
[0062]
That is, when a virtual node is generated, it is inevitable to divide nodes that do not have links from the beginning into different virtual nodes. In the present invention, in addition to this, when there is a link between nodes but there is no resource available and reachability is lost, the node is divided into virtual nodes. As a result, a hierarchical network reflecting the presence or absence of reachability can be configured in real time, so that the efficiency and accuracy of route calculation and packet transfer can be improved.
[0063]
In addition, when the link cost used for data transfer to other nodes in the own virtual node exceeds a threshold based on the monitoring result of the link cost related to the self and the monitoring result of the monitoring means, the self corresponds to the interface. A means for invoking a function as a node belonging to another virtual node of level 1 connected to the self, and updating virtual node information to which the self belongs according to a change of the virtual node to which it belongs, and update contents of the means for updating It is desirable to provide means for advertising and means for updating the virtual node information to which it belongs when receiving the advertisement from another node based on the advertisement.
[0064]
That is, when a virtual node is generated, it is inevitable to divide nodes that do not have links from the beginning into different virtual nodes. In the present invention, in addition to this, even when a link exists between nodes, even when the link cost of the link exceeds a threshold value, the node is divided into virtual nodes. As a result, the link cost via the virtual node can be kept below a certain value. For example, it is possible to realize a hierarchical network in which the link cost is known and no advertisement for link cost information is required.
[0065]
A third aspect of the present invention is a hierarchical network characterized by comprising the nodes of the present invention.
[0066]
A fourth aspect of the present invention is a hierarchical network configuration method according to the present invention. The feature of the present invention is that a layer of a path set for a link between the own virtual node and another virtual node. Accordingly, when a node having a function for terminating the path of the layer terminates the path of the layer, the node is set as a node corresponding to the interface.
[0067]
Alternatively, the hierarchical network configuration method according to the present invention is characterized in that, when there is no available resource for data transfer using a link set between nodes, the nodes are divided into different virtual nodes. .
[0068]
Alternatively, the hierarchical network configuration method of the present invention is characterized in that, when a link cost used for data transfer using a link set between nodes exceeds a threshold, the nodes are divided into different virtual nodes. To do.
[0069]
According to a fifth aspect of the present invention, there is provided a network control apparatus that collectively controls the nodes constituting the hierarchical network of the present invention. The feature of the present invention is that a network between the own virtual node and another virtual node is provided. When a node having a function of terminating the path of the layer according to the layer of the path set for the link terminates the path of the layer, the node includes means for setting the node as a node corresponding to the interface It is in.
[0070]
Alternatively, the network control device of the present invention is characterized by comprising means for dividing the nodes into different virtual nodes when the resources used for data transfer using the link set between the nodes are no longer available. To do.
[0071]
Alternatively, the network control device of the present invention includes means for dividing the nodes into different virtual nodes when the link cost used for data transfer using the link set between the nodes exceeds a threshold value. And
[0072]
DETAILED DESCRIPTION OF THE INVENTION
A hierarchical network according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing how a network is divided into cells, virtual nodes, and hierarchized. FIG. 2 is a diagram showing the topology of the hierarchical network.
[0073]
As shown in Level 1 in FIG. 1, the hierarchical network according to the present embodiment is divided into cells (portions surrounded by broken lines) in which nodes constituting the network are configured by one or a plurality of nodes. 1, the level 1 virtual node constitutes a level 1 virtual network, and the level 1 virtual node constituting the level 1 virtual network further includes a level 2 as shown in Level 2 in FIG. It is divided into cells composed of one or a plurality of virtual nodes to form level 2 virtual nodes, and is constructed by performing such cell division and virtual node operations once or a plurality of N times. A layered network as shown in FIG. 1 is configured by the N-level virtual network. If there is a link that connects different virtual nodes at different levels or different levels, the node corresponding to the contact point between the inside and outside of the virtual node on this link is defined as an interface, and the highest level related to the interface When the virtual node is level M (≦ N), the interface is a hierarchical network that is defined to serve as a multi-level interface from level 1 to level M. In the example of FIG. 1, the level 3 is hierarchized.
[0074]
The nodes constituting the hierarchical network of this embodiment are roughly divided into nodes corresponding to the interfaces and nodes not corresponding to the interfaces. Therefore, in this embodiment, a node corresponding to the interface is called a border node, and a node not corresponding to the interface is called a non-border node. Actually, the border node also has the function of a non-border node. However, in order to make the explanation easy to understand, in the explanation of the border node below, the explanation will focus on functions different from the non-border node. To do.
[0075]
The topology of such a hierarchical network is shown in FIG. The white circles in FIG. 2 are level 1 non-border nodes. The hatched circles in FIG. 2 are level 1 border nodes, which correspond to interfaces. The interface is a level 1 border node but also belongs to level 2. A black circle is a level 1 border node, which also corresponds to an interface. The interface is a level 1 border node but belongs to level 2 and level 3. A thin solid circle is a level 2 virtual node. A thick solid circle is a level 3 virtual node. A thin solid straight line is a level 1 link. A thin broken straight line is a level 2 link. A thick broken line is a level 3 link.
[0076]
(First Example)
The first embodiment relates to a non-border node (white circle). The configuration of the non-border node is shown in FIG. The non-border node of the first embodiment includes an advertisement unit 1 that advertises link information connected to itself to other nodes in the own virtual node and link cost information of the link, and other nodes in the own virtual node. Corresponds to the interface of the own virtual node from the border node corresponding to the interface and the information holding unit 2 in the own virtual node that receives the advertisement of the link information in the own virtual node and the link cost information of the link and holds the information Other virtual node information holding unit 3 that receives advertisement of link information and link cost information of the link between the border node and the border node corresponding to the interface of the virtual node at a higher level than the own virtual node and holds the information It is characterized by comprising.
[0077]
Since the border node is a node having both the function as an interface and the same function as that of the non-border node, the advertisement also carries out both advertisements.
[0078]
Furthermore, an IP address transmission unit 4 that transmits its own IP address to a border node corresponding to the interface of the own virtual node is provided, and the information holding unit 3 in the other virtual node transmits the own IP address transmitted from the border node corresponding to the interface. It holds the IP address of other nodes belonging to a virtual node other than the virtual node and external IP address group information which is information of the virtual node to which the IP address belongs.
[0079]
Next, the border node of the first embodiment will be described with reference to FIG. FIG. 4 is a block diagram of the border node of the first embodiment. The border node of the first embodiment uses the link information in the own virtual node connected to the other node in the own virtual node, the link cost information of the link, and the interface of the other virtual node connected to the own node. An internal advertisement unit 11 that advertises link information between the corresponding border nodes and link cost information of the link, link information in the own virtual node from other nodes in the own virtual node, and link cost information of the link Receives the advertisement and receives the advertisement of the host virtual node information holding unit 2 that holds the information and the link cost information of the higher level link information and the link cost information from the border node corresponding to the interface of the other virtual node. And an other virtual node information holding unit 12 to hold.
[0080]
Further, the IP address information collecting unit 14 that collects and holds IP address information from other nodes in the own virtual node, and the IP address information collected by the IP address information collecting unit 14 corresponds to an interface of another virtual node. The external advertisement unit 15 that advertises to the node, the IP address of the other node belonging to the virtual node other than the own virtual node advertised from the border node corresponding to the interface of the other virtual node, and the information of the virtual node to which the IP address belongs An IP address group information holding unit 16 in other virtual nodes that holds external IP address group information and transmits the information to other nodes in the own virtual node.
[0081]
Next, an example of route search using information held by the non-border node will be described with reference to FIG. FIG. 5 is a diagram for explaining the route search method of the first embodiment. As shown in FIG. 3, the originating node in the route setting shown in FIG. 5 is a destination node position search unit 5 that identifies the virtual node to which the destination node belongs from the IP address of the destination node in the route setting based on the external IP address group information. And the link information between the border node corresponding to the interface of the own virtual node and the border node corresponding to the interface of the virtual node higher in level than the own virtual node and the link cost information of the link. A route search unit 6 that searches for a route to a border node corresponding to the interface of the virtual node to which the destination node specified by 5 belongs.
[0082]
That is, based on the external IP address group information held in the other virtual node information holding unit 3, the destination node position search unit 5 searches for a virtual node to which the destination node belongs. The route search unit 6 searches for a route to the border node of the virtual node based on the link information and link cost information held in the other virtual node information holding unit 3.
[0083]
In the first embodiment, the originating node cannot search for a detailed route in the virtual node to which the destination node belongs. However, if the route to the border node of the virtual node to which the destination node belongs can be searched, the destination node can be searched. Even if the route search to the node is left to the border node, there is no practical problem.
[0084]
(Second embodiment)
The non-border node of the second embodiment will be described with reference to FIG. FIG. 6 is a block diagram of the non-border node of the second embodiment. The non-border node of the second embodiment is basically the same as the configuration of the non-border node of the first embodiment shown in FIG. The difference is that an external IP address group information acquisition unit 7 is added, and the other virtual node information holding unit 3 does not hold external IP address group information.
[0085]
The external IP address group information acquisition unit 7 sends the IP address of another node belonging to a virtual node other than its own virtual node and the external IP address group information which is information of the virtual node to which the IP address belongs to a border node corresponding to the interface. Request and get.
[0086]
Next, a border node according to the second embodiment will be described with reference to FIG. FIG. 7 is a block diagram of the main part of the border node of the second embodiment. The IP address group information holding unit 17 in the other virtual node of the border node of the second embodiment includes the IP address of the other node belonging to the virtual node other than the own virtual node advertised from the border node corresponding to the interface of the other virtual node, and External IP address group information, which is information of a virtual node to which the IP address belongs, is held, and the held external IP address group information is provided to the other node in response to a request from another node. Others are the same as the border node of the first embodiment shown in FIG. The advertisement content of the internal advertisement unit 11 does not need external IP address group information in the second embodiment.
[0087]
The second embodiment is suitable for use in a network environment in which destination nodes frequently move. That is, in the first embodiment, the border node needs to transmit update information to the originating node every time the destination node moves, but in the second embodiment, only when the originating node performs a route search, Since the source node requests the border node to provide information, the border node does not need to transmit update information to the source node every time the destination node moves, and the processing amount is reduced compared to the first embodiment. be able to.
[0088]
(Third embodiment)
A non-border node of the third embodiment will be described with reference to FIG. FIG. 8 is a block diagram of the non-border node of the third embodiment. The non-border node according to the third embodiment transmits the IP address and link cost information between the own IP address and the border node corresponding to the interface of the own virtual node to the border node corresponding to the interface. The IP address of the other node belonging to the virtual node other than the own virtual node transmitted from the border node corresponding to the interface, the external IP address group information which is information of the virtual node to which the IP address belongs, An external IP address group / link cost information holding unit 9 holds link cost information from a border node corresponding to an interface to the other node corresponding to the IP address of the other node.
[0089]
In the non-border node of the third embodiment, the IP address / link cost transmission unit 8 transmits the link cost information to the border node together with its own IP address to the border node.
[0090]
From the border node, the link information in the other virtual node and the external IP address group / link cost information are transmitted and held in the other virtual node information holding unit 3 and the external IP address group / link cost information holding unit 9, respectively. .
[0091]
Based on the external IP address group information held in the external IP address group / link cost information holding unit 9, the destination node position search unit 5 searches for a virtual node to which the destination node belongs. Based on the link information held in the information holding unit 3 in other virtual nodes and the link cost information held in the external IP address group / link cost information holding unit 9, the route search unit 6 Search the route to.
[0092]
Next, a border node according to the third embodiment will be described with reference to FIG. FIG. 9 is a block diagram showing the principal part of a border node according to the third embodiment. As shown in FIG. 9, the border node of the third embodiment collects and holds IP address information and link cost information between the other node and itself from other nodes in the own virtual node. A link cost information collection unit 18; an external advertisement unit 19 that advertises IP address information and link cost information collected by the IP address / link cost information collection unit 18 to a border node corresponding to an interface of another virtual node; The IP address of another node belonging to a virtual node other than its own virtual node advertised from the border node corresponding to the interface of the node, the external IP address group information which is information of the virtual node to which the IP address belongs, and the interface of the other virtual node Link cost information from the border node corresponding to And an external IP address group link cost information collection unit 20 and the internal advertisement unit 21 and transmits the held to correspond to the IP address of the other node to another node in the own virtual node.
[0093]
In the third embodiment, although the originating node cannot search for a detailed route in the virtual node to which the destination node belongs, the route to the border node of the virtual node to which the destination node belongs can be searched, and the border node Since the link cost from the destination node to the destination node is known, the source node can search for the route with the lowest link cost to the destination node.
[0094]
(Fourth embodiment)
A non-border node according to the fourth embodiment will be described with reference to FIG. FIG. 10 is a block diagram of a non-border node according to the fourth embodiment. The non-border node of the fourth embodiment does not hold the external IP address group / link cost information as compared with the third embodiment, and the external IP address group / link cost information acquisition unit 10 The place to request and obtain from the border node is different.
[0095]
Next, a border node according to the fourth embodiment will be described with reference to FIG. FIG. 11 is a block diagram of the main part of the border node of the fourth embodiment. Compared to the border node of the third embodiment shown in FIG. 9, the external IP address group / link cost information collecting unit 22 is advertised from the border node corresponding to the interface of another virtual node. From the border node corresponding to the IP address of the other node belonging to the virtual node other than the assigned virtual node and the external IP address group information which is information of the virtual node to which the IP address belongs and the interface of the other virtual node to the other node The link cost information is held in correspondence with the IP address of the other node, and the held external IP address group information and link cost information are provided to the other node in response to a request from the other node. .
[0096]
When the originating node requests the border node to provide information, by specifying the destination node's IP address, information on the virtual node to which the destination node belongs and the link from the border node to the destination node Since the cost information can be acquired, the minimum necessary information can be obtained, and the processing amount of the border node and the non-border node serving as the originating node can be reduced.
[0097]
Similar to the second embodiment, the fourth embodiment is suitable for use in a network environment in which destination nodes frequently move. That is, in the third embodiment, it is necessary for the border node to transmit updated information to the originating node every time the destination node moves. In the fourth embodiment, when the originating node performs a route search, Since the source node requests the border node to provide information, the border node does not need to transmit update information to the source node every time the destination node moves. The amount can be reduced.
[0098]
(Fifth embodiment)
A non-border node of the fifth embodiment will be described with reference to FIG. FIG. 12 is a block diagram showing the principal part of a non-border node according to the fifth embodiment. As shown in FIG. 12, the non-border node of the fifth embodiment includes a reachability advertisement unit 23 that sends a reachability confirmation packet to a border node corresponding to the interface of the own virtual node. That is, in the first to fourth embodiments, the non-border node has transmitted reachability to a specific border node. In the fifth embodiment, the non-border node is not specified in the own virtual node. Advertise reachability to border nodes. Thereby, as processing of the non-border node, it is only necessary to transmit a reachability advertisement packet, and the processing load can be reduced.
[0099]
The reachability advertisement packet is provided with an advertisement IP header and is set to reach an unspecified border node. In addition, the IP address of the non-border node that is the transmission source is written in the IP header, and the border node that has received the advertisement IP packet can specify the transmission source. Can be confirmed.
[0100]
Next, a border node according to the fifth embodiment will be described with reference to FIG. FIG. 13 is a block diagram showing the principal part of a border node according to the fifth embodiment. The border node according to the fifth embodiment aggregates the reachability advertisement packet receiving unit 24 that receives reachability confirmation packets from other nodes in the own virtual node and the IP address of the received packet. Exchange the generated internal IP address group information between the internal IP address group information generating unit 25 that generates the internal IP address group information related to the node in the node and the other border node in the own virtual node, and the excess or deficiency thereof. Is synchronized with the internal IP address group information unified in the own virtual node and the internal IP address group information unified by the information synchronization unit 26 corresponds to an interface of another virtual node. An external advertising unit 27 that advertises to the border node.
[0101]
FIG. 14 shows the concept of the operation of the fifth embodiment. A non-border node (white circle) transmits a reachability advertisement packet. Upon receiving this, the border node (hatching) synchronizes the internal IP address group information between the border nodes (broken line) and generates unified internal IP address group information. Advertise internal IP address group information.
[0102]
In addition, as shown in FIG. 15, when advertisements from border nodes in a plurality of own virtual nodes are performed on border nodes in the same other virtual node, The border node in one of the own virtual nodes only needs to make an advertisement, thereby eliminating unnecessary advertisements. In order to realize this, as shown in FIG. 16, the external advertisement unit 27 performs an advertisement for determining the presence / absence of an advertisement path from the other border node in the own virtual node to the border node corresponding to the interface of the same other virtual node. An implementation node determination unit 28 is provided, and when the determination result is “present”, the border node corresponding to the interface of the other virtual node is advertised through the advertisement path of either itself or the other border node. .
[0103]
(Sixth embodiment)
A border node according to the sixth embodiment will be described with reference to FIG. FIG. 17 is a block diagram showing the principal part of a border node according to the sixth embodiment. Reachability advertisement packet receiving unit 24 that receives reachability confirmation packets from other nodes in the own virtual node, and an internal IP address group related to the nodes in the own virtual node by aggregating the IP addresses of the received packets An internal IP address group information generation unit 25 that generates information, and an external advertisement unit 27 that advertises the generated internal IP address group information to a border node corresponding to an interface of another virtual node.
[0104]
This is a configuration obtained by removing the information synchronization unit 26 from the border node of the fifth embodiment. Thereby, the inconsistency of the internal IP address group information is allowed between the border nodes in the same virtual node. In other words, even a border node in the same virtual node may have different reachability for a certain non-border node. Therefore, by advertising such a difference, a border node that should not pass in route calculation Can be identified.
[0105]
(Seventh embodiment)
A non-border node according to the seventh embodiment will be described with reference to FIG. FIG. 18 is a block diagram showing the principal part of a non-border node according to the seventh embodiment. The non-border node according to the seventh embodiment includes a link cost calculation unit 30 that calculates link costs for border nodes corresponding to the plurality of interfaces of the own virtual node. In other words, the link cost to each border node in the own virtual node is calculated based on the information held in the information holding unit 3 in the own virtual node.
[0106]
The IP address transmission unit 29 transmits its own IP address by sending a reachability confirmation packet to the border node corresponding to the interface having the lowest link cost according to the calculation result of the link cost calculation unit 30. To do.
[0107]
As a result, the border node can grasp only the IP address of the non-border node having the lowest link cost, and can reduce the amount of information to be aggregated and advertised.
[0108]
(Eighth Example)
A non-border node according to the eighth embodiment will be described with reference to FIG. FIG. 18 is a block diagram of the main part of a non-border node according to the eighth embodiment, which is common with the seventh embodiment. The non-border node of the eighth embodiment includes a link cost calculation unit 30 that calculates link costs for border nodes corresponding to the plurality of interfaces of the own virtual node. In other words, the link cost to each border node in the own virtual node is calculated based on the information held in the information holding unit 3 in the own virtual node.
[0109]
The IP address transmission unit 29 sends reachability confirmation packets to border nodes corresponding to the nth (n is a natural number) interfaces in ascending order of link cost in accordance with the calculation result of the link cost calculation unit 30. To transmit its own IP address.
[0110]
Thereby, the border node can grasp only a small number of IP addresses in ascending order of link cost, and can reduce the amount of information to be advertised in an aggregated manner. Compared with the seventh embodiment, the amount of information to be advertised in a collective manner may increase, but by changing the value of n appropriately, the border node can be adjusted to the amount of information that can be handled most easily under all circumstances. Can do.
[0111]
(Ninth Example)
A non-border node according to the ninth embodiment will be described with reference to FIG. FIG. 18 is a block diagram of the main part of the non-border node of the ninth embodiment, which is common with the seventh and eighth embodiments. As shown in FIG. 18, the non-border node of the ninth embodiment includes link cost calculation units 30 that respectively calculate link costs for border nodes corresponding to the plurality of interfaces of the own virtual node. In other words, the link cost to each border node in the own virtual node is calculated based on the information held in the own virtual node information holding unit 2.
[0112]
The IP address transfer unit 29 is used for reachability confirmation including the order information with respect to border nodes corresponding to the nth (n is a natural number) interfaces in ascending order of link cost in accordance with the calculation result of the rinse cost calculation unit 30. By transmitting this packet, it transmits the IP address and link cost summary information.
[0113]
Thereby, the border node can grasp only a small number of IP addresses in ascending order of link cost, and can reduce the amount of information to be advertised in an aggregated manner. Compared with the eighth embodiment, the link cost outline information can be recognized from the link cost order information. Since it is summary information, the amount of information handled can be reduced compared to the case of handling complete link cost information.
[0114]
The border node in the ninth embodiment, as shown in FIG. 19, is a reachability confirmation packet including information indicating that the other node in the virtual node has the nth lowest link cost for the other node. Reachability confirmation packet receiver 32 and the IP address of the packet received by the reachability confirmation packet receiver 32 for each value of n, and the internal IP address related to the node in the own virtual node An internal IP address group information generation unit 33 that generates group information, and an external advertisement unit that advertises the internal IP address group information generated by the internal IP address group information generation unit 33 to a border node corresponding to an interface of another virtual node 27.
[0115]
(Tenth embodiment)
A non-border node according to the tenth embodiment will be described with reference to FIGS. FIG. 20 is a block diagram showing the principal part of a non-border node according to the tenth embodiment. FIG. 21 is a conceptual diagram of a level 1 scope of a non-border node in the tenth embodiment. As shown in FIG. 20, the non-border node of the tenth embodiment includes an advertisement unit 1 that advertises link information connected to itself to other nodes in the virtual node and link cost information of the link, A host virtual node information holding unit 2 that receives an advertisement of link information and link cost information of the link from another node in the virtual node and holds the information;
[0116]
That is, in the tenth embodiment, as shown in FIG. 21, normally, a non-border node (white circle) holds only information in its own virtual node. As a result, the amount of data handled can be reduced.
[0117]
However, since this cannot calculate the route for the destination in the other virtual node, prior to the route calculation, it corresponds to the border node corresponding to the interface of the own virtual node and the interface of the virtual node at a higher level than the own virtual node. Another virtual node internal information acquisition unit 31 that requests and acquires the link information between the border node and the link cost information of the link from the border node corresponding to the interface is provided.
[0118]
This usually reduces the amount of information by handling only the information in its own virtual node, and reduces the amount of information handled within a certain period of time by acquiring information in other virtual nodes as needed. Can do.
[0119]
(Eleventh Example)
A border node according to the eleventh embodiment will be described with reference to FIGS. FIG. 22 is a block diagram showing the principal part of a border node according to the eleventh embodiment. FIG. 23 is a conceptual diagram of the level 2 scope of the border node according to the eleventh embodiment. As shown in FIG. 22, the border node according to the eleventh embodiment is connected to the border node corresponding to the interface at the same level as that of the border node, and the link information at the same level as that of the border node and the link cost information of the link. The advertisement unit 34 for advertising the link information from the border node corresponding to the interface at the same level as that of the interface corresponding to the interface at the same level as the self and the advertisement of the link cost information of the link and the link cost information of the link are received. The same level border node information holding unit 35 is held. That is, in the eleventh embodiment, as shown in FIG. 23, a border node (hatching) normally holds only information between border nodes at the same level as itself. As a result, the amount of data handled can be reduced.
[0120]
However, since this does not allow the route calculation for the destination in the virtual node at a higher level than the self, the link information between the border nodes corresponding to the interface at the higher level than the self and the link An upper virtual node internal information acquisition unit 36 that requests and acquires link cost information from a border node corresponding to the interface is provided.
[0121]
This usually reduces the amount of information by handling only information between border nodes at the same level as the self, and acquires information in a virtual node at a higher level than the self as necessary, for a certain period of time. Can reduce the amount of information handled.
[0122]
In addition, the combination of the non-border node of the tenth embodiment and the border node of the eleventh embodiment normally allows each level node to handle only information between nodes at the same level as itself, and if necessary, An embodiment that acquires and uses information between nodes at a higher level than the self can be realized.
[0123]
(Twelfth embodiment)
A twelfth embodiment will be described with reference to FIGS. 24 and 25 are diagrams for explaining the route search method of the twelfth embodiment. As the non-border node of the twelfth embodiment, the non-border node shown in FIG. 20 described in the tenth embodiment is used. That is, in the other virtual node obtained by requesting the link information in the virtual node and the link cost information of the link to the border node # 7 corresponding to the interface of the virtual node to which the destination node # 8 shown in FIG. Up to the border node # 7 corresponding to the interface of the virtual node to which the destination node # 8 belongs based on the link information acquired by the information acquisition unit 31 and the in-virtual node information acquisition unit 31 and the link cost information of the link. In addition to the searched route, as shown in FIG. 25, a route search unit 6 for searching for a route from border node # 7 to destination node # 8 corresponding to the interface is provided. Note that the route search from the originating node # 1 to the border node # 7 has already been described in the first embodiment.
[0124]
Further, when the originating node # 1 desires a detailed route search in the virtual node to which the border nodes # 5 and # 6 belong, for example, the other virtual node information acquisition unit 31 selects the border node # 5 or # 6. 6 requesting and obtaining link information in the virtual node and link cost information of the link, and border nodes # 5 and # 6 from itself based on the acquired link information and link cost information of the link. Search for a route in the virtual node to which it belongs.
[0125]
Thereby, the calling node # 1 can acquire information in an arbitrary virtual node and perform a detailed route search.
[0126]
(Thirteenth embodiment)
A route search method according to the thirteenth embodiment will be described with reference to FIGS. FIG. 25 is a diagram for explaining the route searching method of the thirteenth embodiment, and is common to the twelfth embodiment. FIG. 26 is a diagram showing a principal block configuration of a non-border node according to the thirteenth embodiment. FIG. 27 is a sequence diagram for explaining the route searching method of the thirteenth embodiment.
[0127]
In the route search method according to the thirteenth embodiment, the source node # 1 in the route setting determines the virtual node #B to which the destination node # 8 belongs from the IP address of the destination node # 8 in the route setting based on the external IP address group information. Link information between the destination node position search unit 5 to be identified, border node # 2 corresponding to the interface of the own virtual node, and border node # 4 corresponding to the interface of the virtual node at a higher level than the own virtual node, and Based on the link cost information of the link, information indicating which level is the highest level virtual node #A capable of calculating the route from the self to the border node # 4 corresponding to the interface, and corresponding to the interface from the self Results of searching for the top n routes in ascending order of link cost to border node # 4 The route search unit 37 for notifying the destination node # 8 in the route setting is provided, and the destination node # 8 can calculate the route from the source node # 1 to the border node # 4 corresponding to the interface based on the notified information. The route from the self to the border node # 4 corresponding to the interface of the top-level virtual node #A is searched, and the search result is combined with the result of searching the route up to the n-th highest link cost. A route search unit 37 is provided for notifying the originating node # 1 of a route that becomes smaller as a route finally searched.
[0128]
That is, as shown in FIG. 27, the originating node # 1 specifies the location of the destination node # 8 by the destination node location search unit 5 (step 1), and is the highest level virtual node that can be calculated by the route search unit 37 # 4, # 9 and its route are searched (step 2), and the search result is notified to the destination node # 8 (step 3). In destination node # 8, route search unit 37 searches for a route to virtual nodes # 4 and # 9 (step 4), and from source node # 1 notified from source node # 1 to virtual nodes # 4 and # 9. The route with the minimum link cost is selected by adding together with the route (step 5), and the selection result is notified to the originating node # 1 (step 6). The originating node # 1 sets a path with the destination node # 8 based on this notification (step 7). The path may be set from the destination node # 8 (step 8). Step 6 can be omitted when setting a path from the destination node # 8.
[0129]
The advantage of the route search method of the thirteenth embodiment is that, for example, it is necessary to set a large number of paths all at once from a single source node to a large number of destination nodes, and the source node bears all the load required for path setting. In such a case, it is possible to reduce the load required for the route search on the source node side by having the destination node share the load required for the route search.
[0130]
(14th embodiment)
In the fourteenth embodiment, border node setting will be described with reference to FIGS. FIG. 28 and FIG. 29 are diagrams for explaining the definition of a border node. FIG. 30 is a block diagram showing the principal part of a node according to the fourteenth embodiment. Since the hierarchical network of the present embodiment is realized in a multi-layer network, wavelength links, SDH paths, and VPs are mixed in links set between virtual nodes.
[0131]
The node autonomously activates a function as a border node according to a layer of a path set between adjacent virtual nodes among the generated virtual nodes. For example, in FIG. 28, the Lambda layer wavelength path is set between the adjacent virtual nodes. Therefore, an optical cross-connect device corresponding to node2 is set as a border node. In FIG. 29, the IP layer VP is set between the adjacent virtual nodes. Therefore, a router corresponding to node1 is set as a border node. In this way, the end point of the path between adjacent virtual nodes is set as the border node of the virtual node.
[0132]
As shown in FIG. 30, the node of the fourteenth embodiment includes a termination point determination unit 38. The termination point determination unit 38 refers to the link information stored in the other virtual node internal information storage unit 3. If the link connecting the own virtual node and the other virtual node is connected to itself based on the determination result, it is determined whether the link connecting the own virtual node and the other virtual node is connected to itself. It is determined whether or not the terminal corresponds to an end point in the layer of the path set for the link, and when the determination result indicates that the terminal corresponds to the terminal point, it recognizes that the terminal is a border node corresponding to the interface Then, the interface function unit 39 is instructed to activate the function corresponding to the interface.
[0133]
(15th Example)
A fifteenth embodiment will be described with reference to FIGS. 31 and 32. FIG. FIG. 31 is a diagram for explaining a virtual node dividing method according to the fifteenth embodiment. FIG. 32 is a block diagram showing a principal part of a node according to the fifteenth embodiment.
[0134]
When a node is divided into virtual nodes, it is inevitably performed to divide nodes that are not linked from the beginning into different virtual nodes. Although the virtual nodes are divided in this way, in the fifteenth embodiment, as shown in FIG. 31, in the network operation process, a link is set, but resources are not shared between nodes in the same virtual node. When all are used by other nodes and reachability is substantially lost (indicated by a cross in the figure), this is regarded as having no link and is divided into different virtual nodes.
[0135]
This makes it possible to configure a hierarchical network that reflects the presence or absence of substantial reachability compared to the case where it is simply divided into virtual nodes based on the presence or absence of a link, and provides a highly accurate and efficient route search and Packet transfer can be performed.
[0136]
As shown in FIG. 32, the node of the fifteenth embodiment includes a resource usage status monitoring unit 40 that monitors the resource usage status related to itself, and the monitoring result of the resource usage status monitoring unit 40. If the resource used for data transfer to another node is full and the terminal itself corresponds to the interface, the node function unit 41 is instructed to function as a node belonging to another virtual node at level 1 connected to the node. When activated, the virtual node information that the virtual node information holding unit 42 belongs to is updated with the change of the virtual node to which the virtual node information belongs.
[0137]
In addition, the virtual node information holding unit 42 advertises the update contents, and when receiving the advertisement from another node, updates the virtual node information to which the virtual node information holding unit 42 belongs based on the advertisement.
[0138]
(16th Example)
A sixteenth embodiment will be described with reference to FIGS. FIG. 31 is a diagram for explaining a virtual node dividing method according to the sixteenth embodiment, and is common to the fifteenth embodiment. FIG. 33 is a block diagram showing a principal part of a node according to the sixteenth embodiment.
[0139]
When a node is divided into virtual nodes, it is inevitably performed to divide nodes that are not linked from the beginning into different virtual nodes. Although the virtual nodes are divided in this way, in the sixteenth embodiment, as shown in FIG. 31, in the network operation process, a link is set between nodes in the same virtual node although a link is set. Exceeds the threshold (indicated by a cross in the figure), this is regarded as having no link and is divided into different virtual nodes.
[0140]
This makes it possible to configure a hierarchical network that reflects the substantial reachability compared to the case where the virtual nodes are simply divided based on the presence or absence of a link, enabling efficient route search and packet forwarding. It can be carried out.
[0141]
As shown in FIG. 33, the node of the sixteenth embodiment includes a link cost monitoring unit 43 that monitors the link cost related to itself, and other nodes in the own virtual node based on the monitoring result of the link cost monitoring unit 43. If the link cost used for data transfer exceeds a threshold and the device corresponds to the interface, the node function unit 44 is instructed to activate a function as a node belonging to another virtual node at level 1 connected to the node. At the same time, the virtual node information holding unit 42 updates the virtual node information to which the virtual node information belongs, with the change of the virtual node to which the virtual node information belongs.
[0142]
In addition, the virtual node information holding unit 42 advertises this update content, and when receiving the advertisement from another node, updates the virtual node information to which it belongs based on the advertisement.
[0143]
(17th Example)
A node according to the seventeenth embodiment will be described with reference to FIG. FIG. 34 is a block diagram showing the principal part of a node according to the seventeenth embodiment. The node of the seventeenth embodiment is a device that combines the nodes of the fifteenth and sixteenth embodiments. That is, both the resource usage status information between nodes by the resource usage status monitoring unit 40 and the link cost information in the virtual node by the link cost monitoring unit 43 are referred to, and the node function unit 45 is instructed to activate its function. . As a result, virtual node division that incorporates the advantages of both the fifteenth and sixteenth embodiments can be realized.
[0144]
(Eighteenth embodiment)
The eighteenth embodiment is an embodiment of a network control apparatus that collectively controls a hierarchical network. In the eighteenth to twenty-first embodiments, description will be made assuming that one network control device is provided in the hierarchical network. However, the following description is applied to a part of the hierarchical network, and the entire hierarchical network is controlled by a plurality of networks. The embodiment controlled by the apparatus can be similarly described. In the eighteenth embodiment, border node setting will be described with reference to FIGS. 28, 29, and 35. FIG. FIG. 28 and FIG. 29 are diagrams for explaining the definition of a border node. FIG. 35 is a block diagram showing the principal parts of the network control apparatus according to the seventeenth embodiment. Since the hierarchical network of the present embodiment is realized in a multi-layer network, wavelength links, SDH paths, and VPs are mixed in links set between virtual nodes.
[0145]
The network control device sets a border node in accordance with a layer of a path set between adjacent virtual nodes among the generated virtual nodes. For example, in FIG. 28, the Lambda layer wavelength path is set between the adjacent virtual nodes. Therefore, an optical cross-connect device corresponding to node2 is set as a border node. In FIG. 29, the IP layer VP is set between the adjacent virtual nodes. Therefore, a router corresponding to node1 is set as a border node. In this way, the end point of the path between adjacent virtual nodes is set as the border node of the virtual node.
[0146]
As shown in FIG. 35, the network control apparatus of the eighteenth embodiment is provided with a node type database 46, in which information on the types of nodes installed in the network is accumulated. The border node setting unit 47 refers to the node type database 46, recognizes the type of the node in each virtual node, determines a node to be set as the border node according to the layer of the link with the adjacent virtual node, A setting instruction is sent to the node. Upon receiving this setting instruction, the node recognizes that it is a border node and activates the function as a border node.
[0147]
(Nineteenth Example)
A nineteenth embodiment will be described with reference to FIGS. FIG. 31 is a diagram for explaining a virtual node dividing method according to the nineteenth embodiment, and is common to the fifteenth and sixteenth embodiments. FIG. 36 is a block diagram showing the principal parts of the network control apparatus according to the nineteenth embodiment.
[0148]
When a node is divided into virtual nodes, it is inevitably performed to divide nodes that are not linked from the beginning into different virtual nodes. Although the virtual nodes are divided in this way, in the nineteenth embodiment, as shown in FIG. 31, in the network operation process, although links are set, resources are not shared between nodes in the same virtual node. When all are used by other nodes and reachability is substantially lost (indicated by a cross in the figure), this is regarded as having no link and is divided into different virtual nodes.
[0149]
This makes it possible to configure a hierarchical network that reflects the presence or absence of substantial reachability compared to the case where it is simply divided into virtual nodes based on the presence or absence of a link, and provides a highly accurate and efficient route search and Packet transfer can be performed.
[0150]
As shown in FIG. 36, the network control apparatus of the nineteenth embodiment includes a resource usage status monitoring unit 48 that monitors the resource usage status of each node, and the virtual node division control unit 49 includes a resource usage status monitoring unit 48. As necessary, each node is instructed to divide a new virtual node. Upon receiving this instruction, the node updates the information of the virtual node to which it belongs, and activates the function as a new node within the virtual node.
[0151]
(20th embodiment)
A twentieth embodiment will be described with reference to FIGS. 31 and 37. FIG. FIG. 31 is a diagram for explaining a virtual node dividing method of the twentieth embodiment, and is common to the fifteenth, sixteenth and nineteenth embodiments. FIG. 37 is a block diagram showing the principal part of the network control apparatus according to the twentieth embodiment.
[0152]
When a node is divided into virtual nodes, it is inevitably performed to divide nodes that are not linked from the beginning into different virtual nodes. Although the virtual nodes are divided in this way, in the 20th embodiment, as shown in FIG. 31, in the network operation process, the link cost is set between the nodes in the same virtual node although the link is set. Exceeds the threshold (indicated by a cross in the figure), this is regarded as having no link and is divided into different virtual nodes.
[0153]
This makes it possible to configure a hierarchical network that reflects the substantial reachability compared to the case where the virtual nodes are simply divided based on the presence or absence of a link, enabling efficient route search and packet forwarding. It can be carried out.
[0154]
As shown in FIG. 37, the network control apparatus of the twentieth embodiment includes a link cost monitoring unit 50 that monitors the link cost of each node, and the virtual node division control unit 51 refers to the link cost monitoring unit 50. At any time, it instructs each node to divide a new virtual node. Upon receiving this instruction, the node updates the information of the virtual node to which it belongs, and activates the function as a new node within the virtual node.
[0155]
By using the virtual node dividing method described in the twentieth embodiment, the link cost in each virtual node can be kept constant. Therefore, there is an advantage that there is no need to advertise the link cost information to the outside. For example, the threshold value is the link cost value of the virtual node with the lowest link cost so that the link cost of each virtual node is constant.
[0156]
(21st Example)
A network control apparatus according to the twenty-first embodiment will be described with reference to FIG. FIG. 38 is a block diagram showing the principal part of the network control apparatus according to the 21st embodiment. The network control device of the twenty-first embodiment is a device that combines the network control devices of the nineteenth and twenty-first embodiments. That is, referring to both the resource usage status information between nodes by the resource usage status monitoring unit 48 and the link cost information in the virtual node by the link cost monitoring unit 50, the virtual node division control unit 52 instructs the virtual node division. To do. As a result, it is possible to realize virtual node division that adopts the advantages of both the nineteenth and twenty embodiments.
[0157]
【The invention's effect】
As described above, according to the present invention, even a network that requires complex processing such as a multi-layer network can be extended to a large-scale network, and further, route calculation is required. Since the calculation can be performed after the range to be specified is specified, invalid calculations can be eliminated, and the route calculation can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a diagram showing how a network is divided into cells, virtual nodes, and hierarchized.
FIG. 2 is a diagram showing a topology of a hierarchical network.
FIG. 3 is a block diagram of a non-border node according to the first embodiment.
FIG. 4 is a block diagram of a border node according to the first embodiment.
FIG. 5 is a diagram for explaining a route search method according to the first embodiment;
FIG. 6 is a block diagram of a non-border node according to the second embodiment.
FIG. 7 is a block diagram of a main part of a border node according to a second embodiment.
FIG. 8 is a block diagram of a non-border node according to the third embodiment.
FIG. 9 is a block diagram of a main part of a border node according to a third embodiment.
FIG. 10 is a block diagram of a non-border node according to a fourth embodiment.
FIG. 11 is a block diagram of a main part of a border node according to a fourth embodiment.
FIG. 12 is a block diagram of the main part of a non-border node according to the fifth embodiment.
FIG. 13 is a block diagram of a main part of a border node according to a fifth embodiment.
FIG. 14 is a diagram showing the concept of operation of a fifth embodiment.
FIG. 15 is a diagram showing a case where an advertisement is made from a border node in a plurality of own virtual nodes to a border node in the same other virtual node;
FIG. 16 is a block diagram of an external advertising unit according to a fifth embodiment.
FIG. 17 is a block diagram of a main part of a border node according to a sixth embodiment.
FIG. 18 is a block diagram of a main part of a non-border node according to seventh, eighth, and ninth embodiments.
FIG. 19 is a block diagram of a main part of a border node according to a ninth embodiment.
FIG. 20 is a block diagram of the main part of a non-border node according to the tenth embodiment.
FIG. 21 is a conceptual diagram of a level 1 scope of a non-border node in a tenth embodiment.
FIG. 22 is a block diagram of the main part of a border node according to the eleventh embodiment.
FIG. 23 is a conceptual diagram of a level 2 scope of a border node according to the eleventh embodiment.
FIG. 24 is a diagram for explaining a route search method according to the twelfth embodiment.
FIG. 25 is a diagram for explaining a route search method according to the thirteenth embodiment;
FIG. 26 is a block diagram showing the principal parts of a non-border node according to the thirteenth embodiment.
FIG. 27 is a sequence diagram for explaining a route search method according to the thirteenth embodiment;
FIG. 28 is a diagram for explaining the definition of a border node.
FIG. 29 is a diagram for explaining the definition of a border node;
FIG. 30 is a block diagram showing the principal part of a node according to the fourteenth embodiment.
FIG. 31 is a diagram for explaining a virtual node dividing method according to the fifteenth, sixteenth, nineteenth, and twenty-first embodiments;
FIG. 32 is a block diagram showing the principal part of a node according to the fifteenth embodiment.
FIG. 33 is a block diagram showing the principal part of a node according to the sixteenth embodiment.
FIG. 34 is a block diagram showing the principal part of a node according to the seventeenth embodiment.
FIG. 35 is a block diagram showing the principal part of the network control apparatus according to the eighteenth embodiment.
FIG. 36 is a block diagram showing the principal part of the network control apparatus according to the nineteenth embodiment.
FIG. 37 is a block diagram showing the principal part of the network control apparatus according to the twentieth embodiment.
FIG. 38 is a block diagram showing the principal part of the network control apparatus according to the twenty-first embodiment.
FIG. 39 is a diagram showing an example of a network configured with a plurality of layers of networks.
[Explanation of symbols]
# 1 to # 9 nodes
#A, #B Virtual node
1,34 Advertising Department
2 Self-virtual node information storage unit
3 Other virtual node information storage unit
4, 29 IP address transmission part
5 Landing node location search unit
6, 37 Route search unit
7 External IP address group information acquisition unit
8 IP address / link cost transmission part
9 External IP address group / link cost information holding unit
10 External IP address group / link cost information acquisition unit
11 Internal Advertising Department
13 Information holding unit in other virtual node
14 IP address information collection unit
15 External Advertising Department
16 IP address group information holding unit in other virtual node
17 IP address group information holding unit in other virtual node
18 IP address / link cost information collection part
19 External Advertising Department
20 External IP address group / link cost information collection part
21 Internal Advertising Department
22 External IP address group / link cost information collection part
23 Reachability Advertising Department
24 Reachability advertisement packet receiver
25 Internal IP address group information generator
26 Information synchronization section
27 External Advertising Department
28 Advertisement implementation node determination unit
30 Link cost calculator
31 Other virtual node information acquisition unit
32 Reachability confirmation packet receiver
33 Internal IP address group information generator
35 Same level border node information holding unit
36 Upper virtual node information acquisition unit
38 End point determination unit
39 Interface function part
40, 48 Resource usage monitor
41, 44, 45 Node function part
42 Virtual node information holding unit
43, 50 Link cost monitoring unit
46 Node type database
47 Border node setting section
49, 51, 52 Virtual node division control unit

Claims (36)

The nodes constituting the network are divided into cells composed of one or a plurality of nodes, and this cell is defined as a level 1 virtual node, and this level 1 virtual node constitutes a level 1 virtual network, and A level 1 virtual node constituting a level 1 virtual network is further divided into cells constituted by one or a plurality of virtual nodes to form level 2 virtual nodes. A layered network is configured by 1 to N level virtual networks constructed by performing the above operation once or a plurality of N times. In the layered network, different virtual nodes of the same level or different levels are connected. If there is a link, the node corresponding to the contact point between the inside and outside of the virtual node on this link Is defined as an interface, and when the highest virtual node related to the interface is level M (≦ N), the interface is defined in the hierarchical network defined to serve as a multi-level interface from levels 1 to M. In the nodes that make up the level 1 virtual node,
Means for advertising link information connected to itself to other nodes in the virtual node and link cost information of the link;
Means for receiving the link information in the own virtual node and the link cost information of the link from other nodes in the own virtual node and holding the information;
Receives advertisement of link information and link cost information of the link between the node corresponding to the interface corresponding to the interface in the own virtual node and the node corresponding to the interface of the virtual node of level 2 or higher, and holds the information A node characterized by comprising means. Means for transmitting its own IP address to a node corresponding to the interface of its own virtual node;
A means for holding an IP address of another node belonging to a virtual node other than the own virtual node transmitted from a node corresponding to the interface and external IP address group information which is information of a virtual node to which the IP address belongs. Item 1. The node according to item 1. Means for transmitting its own IP address to a node corresponding to the interface of its own virtual node;
And a means for requesting and obtaining an IP address of another node belonging to a virtual node other than its own virtual node and external IP address group information, which is information of a virtual node to which the IP address belongs, from a node corresponding to the interface. Item 1. The node according to item 1. Means for transmitting link cost information between the own IP address and the node corresponding to the interface of the self and the virtual node to the node corresponding to the interface;
From the node corresponding to the interface, the IP address of the other node belonging to the virtual node other than the own virtual node transmitted from the node corresponding to the interface, the external IP address group information that is information of the virtual node to which the IP address belongs, and the node corresponding to the interface The node according to claim 1, further comprising means for holding link cost information to another node corresponding to the IP address of the other node. Means for transmitting link cost information between the own IP address and the node corresponding to the interface of the self and the virtual node to the node corresponding to the interface;
The IP address of the other node belonging to the virtual node other than the own virtual node, the external IP address group information which is information of the virtual node to which the IP address belongs, and the link cost information from the node corresponding to the interface to the other node The node according to claim 1, further comprising: a unit that specifies and obtains an IP address of the node to request and acquire a node corresponding to the interface. The node according to claim 1, further comprising means for transmitting a reachability confirmation packet to a node corresponding to the interface of the own virtual node. Means for calculating link costs for nodes corresponding to the plurality of interfaces of the own virtual node,
7. The node according to claim 6, wherein the sending means comprises means for sending a reachability confirmation packet to a node corresponding to the interface having the lowest link cost according to a calculation result of the calculating means. Means for calculating link costs for nodes corresponding to the plurality of interfaces of the own virtual node,
The sending means includes means for sending a reachability confirmation packet to nodes corresponding to the nth (n is a natural number) interface in ascending order of link cost according to the calculation result of the calculating means. The node according to claim 6. Means for calculating link costs for nodes corresponding to the plurality of interfaces of the own virtual node,
The sending means sends reachability confirmation packets including the order information to nodes corresponding to the nth (n is a natural number) interface in ascending order of link cost according to the calculation result of the calculating means. The node according to claim 6, further comprising means for: The nodes constituting the network are divided into cells composed of one or a plurality of nodes, and this cell is defined as a level 1 virtual node, and this level 1 virtual node constitutes a level 1 virtual network, and A level 1 virtual node constituting a level 1 virtual network is further divided into cells constituted by one or a plurality of virtual nodes to form level 2 virtual nodes. A layered network is configured by 1 to N level virtual networks constructed by performing the above operation once or a plurality of N times. In the layered network, different virtual nodes of the same level or different levels are connected. If there is a link, the node corresponding to the contact point between the inside and outside of the virtual node on this link Is defined as an interface, and when the highest virtual node related to the interface is level M (≦ N), the interface is defined in the hierarchical network defined to serve as a multi-level interface from levels 1 to M. In the nodes that make up the level 1 virtual node,
Means for advertising link information connected to itself to other nodes in the virtual node and link cost information of the link;
A node comprising: means for receiving an advertisement of link information and link cost information of the link from another node in the virtual node and holding the information. Prior to the route calculation, the link information between the node corresponding to the interface of the own virtual node and the node corresponding to the interface of the virtual node of level 2 or higher and the link cost information of the link are requested to the node corresponding to the interface. The node according to claim 10, further comprising means for acquiring the information. The nodes constituting the network are divided into cells composed of one or a plurality of nodes, and this cell is defined as a level 1 virtual node, and this level 1 virtual node constitutes a level 1 virtual network, and A level 1 virtual node constituting a level 1 virtual network is further divided into cells constituted by one or a plurality of virtual nodes to form level 2 virtual nodes. A layered network is configured by 1 to N level virtual networks constructed by performing the above operation once or a plurality of N times. In the layered network, different virtual nodes of the same level or different levels are connected. If there is a link, the node corresponding to the contact point between the inside and outside of the virtual node on this link Is defined as an interface, and when the highest virtual node related to the interface is level M (≦ N), the interface is defined in the hierarchical network defined to serve as a multi-level interface from levels 1 to M. In the nodes that make up the level 1 virtual node,
If self corresponds to the interface,
Link information in the own virtual node connected to itself with respect to other nodes in the own virtual node, link cost information of the link, and link information between nodes corresponding to interfaces of other virtual nodes connected to the own virtual node And means for advertising link cost information for the link;
Means for receiving the link information in the own virtual node and the link cost information of the link from other nodes in the own virtual node and holding the information;
And means for receiving an advertisement of link information between nodes corresponding to the interface at a higher level from a node corresponding to the interface of another virtual node and link cost information of the link and holding the information. Node to perform. Means for collecting and holding IP address information from other nodes within the own virtual node;
Means for advertising the IP address information collected by the means for collecting and holding to a node corresponding to an interface of another virtual node;
Holds the IP address of the other node belonging to the virtual node other than the own virtual node advertised from the node corresponding to the interface of the other virtual node and the external IP address group information which is information of the virtual node to which the IP address belongs, and 13. The node according to claim 12, further comprising means for transmitting to other nodes in the node. Means for collecting and holding IP address information from other nodes within the own virtual node;
Means for advertising the IP address information collected by the means for collecting and holding to a node corresponding to an interface of another virtual node;
Means for holding an IP address of another node belonging to a virtual node other than the own virtual node advertised from a node corresponding to the interface of the other virtual node and external IP address group information which is information of the virtual node to which the IP address belongs;
13. The node according to claim 12, further comprising means for providing external IP address group information held in the holding means to the other node in response to a request from the other node. Means for collecting and holding IP address information and link cost information between the other node and itself from another node in the own virtual node;
Means for advertising the IP address information and link cost information collected by the means for collecting and holding to a node corresponding to an interface of another virtual node;
The IP address of the other node belonging to the virtual node other than the own virtual node advertised from the node corresponding to the interface of the other virtual node, the external IP address group information which is information of the virtual node to which the IP address belongs, and the other virtual node 13. A node according to claim 12, further comprising means for holding link cost information from a node corresponding to the interface to the other node in correspondence with an IP address of the other node and transmitting the link cost information to the other node in the own virtual node. . Means for collecting and holding IP address information and link cost information between the other node and itself from another node in the own virtual node;
Means for advertising the IP address information and link cost information collected by the means for collecting and holding to a node corresponding to an interface of another virtual node;
The IP address of the other node belonging to the virtual node other than the own virtual node advertised from the node corresponding to the interface of the other virtual node, the external IP address group information which is information of the virtual node to which the IP address belongs, and the other virtual node Means for holding link cost information from the node corresponding to the interface to the other node corresponding to the IP address of the other node;
13. The node according to claim 12, further comprising means for providing external IP address group information and link cost information held in the holding means to the other node in response to a request from the other node. Means for receiving a reachability confirmation packet from another node in its own virtual node;
Means for aggregating the IP addresses of the packets received by the means for receiving to generate internal IP address group information relating to nodes in the own virtual node;
A unified internal IP address group in the own virtual node by exchanging the internal IP address group information generated by the generating means with another node corresponding to the interface in the own virtual node and correcting the excess or deficiency Means for synchronizing as information,
13. The node according to claim 12, further comprising means for advertising internal IP address group information unified by the means for synchronizing to a node corresponding to an interface of another virtual node. The means for advertising is:
Means for determining the presence / absence of an advertising route from another node corresponding to the interface in the own virtual node to a node corresponding to the interface of the same other virtual node;
And a means for performing an advertisement to a node corresponding to the interface of the other virtual node through one of the advertising paths of itself or the other node when the determination result of the determining means is “Yes”. Item 12. The node according to item 12. Means for receiving a reachability confirmation packet from another node in its own virtual node;
Means for aggregating the IP addresses of the packets received by the means for receiving to generate internal IP address group information relating to nodes in the own virtual node;
13. The node according to claim 12, further comprising means for advertising the internal IP address group information generated by the generating means to a node corresponding to an interface of another virtual node. Means for receiving a reachability confirmation packet including information indicating that the link cost is nth lowest for the other node from another node in the virtual node;
Means for aggregating the IP addresses of the packets received by the means for receiving for each value of n and generating internal IP address group information relating to a node in the own virtual node;
13. The node according to claim 12, further comprising means for advertising the internal IP address group information generated by the generating means to a node corresponding to an interface of another virtual node. The nodes constituting the network are divided into cells composed of one or a plurality of nodes, and this cell is defined as a level 1 virtual node, and this level 1 virtual node constitutes a level 1 virtual network, and A level 1 virtual node constituting a level 1 virtual network is further divided into cells constituted by one or a plurality of virtual nodes to form level 2 virtual nodes. A layered network is configured by 1 to N level virtual networks constructed by performing the above operation once or a plurality of N times. In the layered network, different virtual nodes of the same level or different levels are connected. If there is a link, the node corresponding to the contact point between the inside and outside of the virtual node on this link Is defined as an interface, and when the highest virtual node related to the interface is level M (≦ N), the interface is defined in the hierarchical network defined to serve as a multi-level interface from levels 1 to M. In the nodes that make up the level 1 virtual node,
If self corresponds to the interface,
Means for advertising link information of the same level as the self connected to a node corresponding to an interface of the same level as the self and link cost information of the link;
A means for receiving an advertisement of link information between nodes corresponding to an interface at the same level as the self and a link cost information of the link from a node corresponding to the interface at the same level as the self and holding the information Node to be 22. A means for requesting and acquiring link information between a node corresponding to an interface at a higher level than itself and link cost information of the link from a node corresponding to the interface prior to route calculation. The listed node. The source node in route setting is
Means for identifying the virtual node to which the destination node belongs from the IP address of the destination node in route setting based on the external IP address group information;
The destination node specified by the specifying means based on the link information between the node corresponding to the interface of the own virtual node and the node corresponding to the interface of the virtual node of level 2 or higher and the link cost information of the link belongs. 4. The node according to claim 1, further comprising means for searching for a route to a node corresponding to the interface of the virtual node. Means for requesting and obtaining link information in the virtual node and link cost information of the link from a node corresponding to the interface of the virtual node to which the destination node belongs;
In addition to the route searched by the means for searching for the route to the node corresponding to the interface of the virtual node to which the destination node belongs based on the link information acquired by the requesting and acquiring unit and the link cost information of the link The node according to claim 23, further comprising means for searching for a route from a node corresponding to the interface to the destination node. Means for requesting and obtaining link information in the virtual node and link cost information of the link from a node corresponding to the interface of the virtual node included in the path from the self to the destination node;
The means for searching for a route in a virtual node included in a route from itself to the destination node based on the link information acquired by the requesting and acquiring unit and the link cost information of the link. node. The source node in route setting is
Means for identifying the virtual node to which the destination node belongs from the IP address of the destination node in route setting based on the external IP address group information;
Based on the link information between the node corresponding to the interface of the own virtual node and the node corresponding to the interface of the virtual node of level 2 or higher and the link cost information of the link, it is possible to calculate the route from the node corresponding to the interface to the node corresponding to the interface. Information indicating which level is the highest virtual node and the result of searching for the top n routes in ascending order of link cost from the node to the node corresponding to the interface as the destination node in route setting With a means of notification,
The destination node searches for a route from itself to a node corresponding to the interface of the highest-level virtual node capable of calculating a route from the source node to a node corresponding to the interface based on the notified information. And a means for notifying the originating node of the route having the lowest link cost as a finally searched route by combining the search result with the result of searching for the top n routes. A node according to one of the following. Means for referring to the link information held in the holding means to determine whether or not a link connecting the own virtual node and another virtual node is connected to itself;
Based on the determination result of the determination means, when a link connecting the own virtual node and another virtual node is connected to itself, it is determined whether or not the self corresponds to an end point in the layer of the path set for the link Means to
27. A means for recognizing that the node is a node corresponding to the interface when the terminal corresponds to the termination point based on a determination result of the determining means, and a means for activating a function corresponding to the interface. The node described in any of the above. A means of monitoring resource usage related to self,
Nodes belonging to other virtual nodes at level 1 connected to the self when the resources used for data transfer to other nodes in the own virtual node are free based on the monitoring result of the monitoring means and the self corresponds to the interface Means for invoking the function as and updating the virtual node information to which the self belongs as the virtual node to which it belongs is changed,
Means for advertising the updated content of the means for updating;
27. The node according to any one of claims 1 to 26, further comprising means for updating virtual node information to which the self belongs based on the advertisement when the advertisement is received from another node. A means of monitoring the link cost associated with it;
If the link cost used for data transfer to other nodes in the own virtual node exceeds the threshold based on the monitoring result of the monitoring means, and the self corresponds to the interface, it belongs to the other virtual node of level 1 connected to the own node Means for invoking the function as a node and updating the virtual node information to which the self belongs as the virtual node to which it belongs is changed,
Means for advertising the updated content of the means for updating;
27. The node according to any one of claims 1 to 26, further comprising means for updating virtual node information to which the self belongs based on the advertisement when the advertisement is received from another node. A hierarchical network comprising the nodes according to any one of claims 1 to 29. 31. The hierarchical network configuration method according to claim 30, wherein a node having a function of terminating a path of the layer according to a layer of a path set in a link between the own virtual node and another virtual node is the layer. A hierarchical network configuration method, characterized in that when the path of (1) is terminated, the node is set as a node corresponding to the interface. 31. The hierarchical network configuration method according to claim 30, wherein when there is no available resource for data transfer using a link set between nodes, the nodes are divided into different virtual nodes. How to configure a hierarchical network. 31. The hierarchical network configuration method according to claim 30, wherein when a link cost used for data transfer using a link set between nodes exceeds a threshold, the nodes are divided into different virtual nodes. To configure a hierarchical network. A network control apparatus for collectively controlling nodes constituting the hierarchical network according to claim 30,
When a node having a function of terminating the path of the layer according to the layer of the path set in the link between the own virtual node and another virtual node terminates the path of the layer, the node is used as the interface. A network control apparatus comprising means for setting as a corresponding node. A network control apparatus for collectively controlling nodes constituting the hierarchical network according to claim 30,
A network control device comprising means for dividing a node between different nodes into different virtual nodes when a resource used for data transfer using a link set between the nodes runs out. A network control apparatus for collectively controlling nodes constituting the hierarchical network according to claim 30,
A network control apparatus comprising: means for dividing a node between different nodes into different virtual nodes when a link cost used for data transfer using a link set between the nodes exceeds a threshold value.

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