JPH09247199A - Multicast connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize efficiently a frequency band resource by providing an m- layer consisting of a 1st layer sub network and plural (m-1) layers of sub networks so as to connect an outgoing terminal equipment to each incoming terminal equipment in a very short time. SOLUTION: Two-layer sub networks SN1, SN2 are interconnected by a link L6 and an incoming terminal equipment LF4 is connected to the 2-layer sub network SN2 via a link L4. Furthermore, two-layer sub networks SN1, SN3 are interconnected by a link L7 and two-layer sub networks SN3, SN4 are interconnected by a link L8 respectively and an incoming terminal equipment LF5 is connected to the 2-layer sub network SN4 via a link L5. Each of the two layer sub networks SN1-SN4 is provided with each of 2-layer sub net managers SM1-SM4 managing the sub network. SN11-SN13 of the 2-layer sub network SN1 are a 1-layer sub networks being subordinate to the sub network SN1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicast connection method, and more particularly to a multicast connection method for simultaneously connecting / releasing a plurality of terminals via a network composed of a plurality of switching nodes.

[0002]

2. Description of the Related Art Using a network composed of a plurality of switching nodes, voice having a CBR (Constant Bit Rate) traffic characteristic in which data is transmitted to the network at an equal speed and a large amount of data in a short period of time are transmitted. When sending computer-processed image information with bursty traffic characteristics to multiple terminals all at once, a virtual circuit (Virtual Channel: VC) connection request from the calling terminal is sent. Accordingly, while determining the route connecting the calling terminal and each called terminal and reserving the bandwidth based on the required transmission capacity,
It is necessary to release the reserved bandwidth in response to the VC release request after the communication is completed.

Conventionally, studies have been made on such a multicast connection method. For example, ITU and ATM
In Forum, first, the calling terminal and an arbitrary called terminal are set to 1:
After connecting with 1, the other destination terminal is connected to 1 party (part
A method has been proposed in which the source terminal and a plurality of destination terminals are connected by multicast by increasing or decreasing each by y).

[0004]

Therefore, in such a conventional multicast connection method, the number of each destination terminal is increased or decreased by one party. Therefore, in order to connect a plurality of parties collectively, It is necessary to establish a VC for 1: 1 connection between the terminal and each destination terminal separately, and there are multiple VCs on the same link, so that the bandwidth resources of the network are not used efficiently and the call loss rate is increased. There was a problem. The present invention is intended to solve such a problem, and provides a multicast connection method capable of connecting a source terminal and each destination terminal in a short time and efficiently using bandwidth resources of the network. Is intended.

[0005]

In order to achieve such an object, a multicast connection method according to the present invention is a sub-layer of a first layer in which a network is composed of a plurality of switching nodes mutually connected by a predetermined link. Network,
It has a hierarchical structure composed of a plurality of m-1 layer (m is a positive integer of 2 or more) sub-networks connected to each other by a predetermined link, and the m-th layer has a hierarchical structure. In response to a multicast connection request from the switching node accommodating the terminal or the (m + 1) th layer, each mth layer sub that configures this multicast connection route based on a predetermined multicast connection route that connects each mth layer subnetwork by multicast A bandwidth reservation request is sent to the inter-network links in parallel, and a multicast connection is requested within each m-th layer sub-network for each m-th layer sub-network that constitutes a connection route for which the band reservation has been successful. Multicast connection requests are sent in parallel, and the m-th layer sub-network responds to the multicast connection request from the m-th layer. Then, the multicast connection request in the m-1th layer is sent to the m-1st layer in the mth layer subnetwork, and in the 1st layer, the multicast from the switching node accommodating the calling terminal or the 2nd layer. According to the connection request, based on a predetermined multicast connection route for performing a multicast connection between the first layer sub-networks, a bandwidth reservation request is made in parallel to the first layer sub-network links forming the multicast connection route. A multicast connection request for sending a multicast connection within each individual first layer sub-network is sent in parallel to each first layer sub-network constituting the connection route for which bandwidth reservation has been successful, and the first layer In the sub-network, in accordance with the multicast connection request from the first layer, the multicast connection is established between each switching node. Based on a predetermined multicast connection route, a bandwidth reservation request is sent in parallel to the links between the exchange nodes that make up this multicast connection route, and each exchange node requests the bandwidth reservation request for the link to accommodate. The bandwidth is reserved according to the communication capacity of the.

Therefore, in each layer, a bandwidth reservation request is sent in parallel to the hierarchical inter-subnetwork links on the basis of a predetermined multicast connection route, and the sub-networks constituting the connection route for which the bandwidth reservation is successful are transmitted to each sub-network. Then, the multicast connection requests in each sub-network are connected in parallel, the multicast connection request is sent to the lower layer in each sub-network, and such parallel multicast connection processing is configured from the switching node. It is repeated until the first layer.

[0007] As each multicast connection route, among the multicast connection routes having the same originating and terminating end points, the one that has the smallest number of sub-networks or switching nodes to pass through is used. . Therefore, as each multicast connection route, among the multicast connection routes having the same originating and terminating end points, the multicast connection route having the smallest number of sub-networks or switching nodes to be used is used.

Further, as each multicast connection route, among the multicast connection routes having the same originating and terminating end points, the multicast connection route having the smallest number of sub-networks or the number of exchange nodes to pass through, and the multicast The multicast connection route having the largest reservable bandwidth amount of each link constituting the connection route is used. Therefore, for each multicast connection route, among the multicast connection routes that have the same originating and terminating end points, the one that has the smallest number of sub-networks or switching nodes to pass through and that multicast connection route The multicast connection route with the largest reservable bandwidth amount of each link to be used is used.

Of the multicast connection routes,
When the bandwidth reservation request fails on the predetermined connection route, a predetermined one-to-one correspondence is established between the destination endpoint on the connection route for which the bandwidth reservation has failed and the originating endpoint on the multicast connection route.
The connection request is sent out. Therefore, when the bandwidth reservation request fails in a predetermined connection route among the multicast connection routes, a predetermined distance is set between the destination end point on the connection route for which the bandwidth reservation has failed and the origination end point of the multicast connection route. A one-to-one connection request is sent.

Further, a call identifier for identifying a multicast connection request from the calling terminal is stored in all requests derived from the multicast connection request, and the switching node is based on the call identifier included in the received bandwidth reservation request. Then, it is determined whether or not the bandwidth reservation request is made by the same multicast connection request, and when the bandwidth reservation is made by the same multicast connection request, the new bandwidth reservation is not made. Therefore, the call identifier for identifying the multicast connection request from the calling terminal is
It is stored in all requests derived from the multicast connection request, and the switching node judges whether or not the bandwidth reservation request is due to the same multicast connection request based on the call identifier included in the received bandwidth reservation request. When the bandwidth is reserved by the request, no new bandwidth is reserved.

Further, the multicast connection route at the end of the multicast connection is held for each layer, and
In the layer, in response to the multicast release request from the switching node accommodating the source terminal or the m + 1th layer, the bandwidth release request is parallelized to each of the m-th layer inter-subnetwork links forming the held multicast connection route. Each m-th packet on the multicast connection route
A multicast release request for requesting multicast release in each m-th layer sub-network is sent in parallel to the layer sub-network, and the m-th layer sub-network responds to the multicast release request from the m-th layer by A multicast release request in the m-1 layer is sent to the m-1 layer in the m-layer sub-network, and a multicast release request from the switching node accommodating the calling terminal or the second layer is sent in the 1st layer. Accordingly, a bandwidth release request is sent in parallel to each inter-layer-1 sub-network link that constitutes the retained multicast connection route, and to each first-layer sub-network on the multicast connection route. Parallel multicast release requests that request multicast release within each Layer 1 subnetwork Delivery, the first layer subnetwork, according to the multicast release request from the first layer, parallel sends a bandwidth release request to the switching node links constituting a multicast connection route that held,
Each switching node releases a desired band in response to a band releasing request for the link to be accommodated.

Therefore, in each layer, based on the multicast connection route held at the end of the multicast connection, a bandwidth release request is sent in parallel to the hierarchical inter-subnetwork links, and at the same time each sub-node constituting the multicast connection route is sent. Multicast release requests within each subnetwork are connected in parallel to the network, and multicast release requests are sent to the lower layers in each subnetwork. Such parallel multicast release processing is performed from the switching node. The process is repeated until the first layer is formed.

Further, in a layer one layer below the layer in which the calling terminal and all the called terminals are accommodated in the same sub-network, in response to a predetermined routing registration request from the calling terminal,
Of the multicast connection routes that have the originating terminal as the originating end point and all destination terminals as the terminating side endpoint, configure each multicast connection route with the smallest number of sub-networks or switching nodes to pass through. Start the process of sequentially reordering the links in descending order of reservable bandwidth, then select the multicast connection route with the largest reservable bandwidth and perform the multicast connection processing in response to the multicast connection request from the calling terminal. The rearrangement processing of the multicast connection routes is stopped in response to a predetermined routing deletion request from the calling terminal.

Therefore, in the layer immediately below the layer in which the calling terminal and all the called terminals are accommodated in the same sub-network, among the target multicast connection routes in response to a predetermined routing registration request from the calling terminal, A process is started to sequentially sort the multicast connection routes with the smallest number of sub-networks or switching nodes to pass through, in descending order of the reservable bandwidth for each link, and then to make a reservation in response to a multicast connection request from the calling terminal. The multicast connection route with the largest available bandwidth is selected and multicast connection processing is performed, and in response to a predetermined routing deletion request from the calling terminal,
The process of rearranging the multicast connection routes is stopped.

[0015]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a hierarchical network system according to an embodiment of the present invention. In FIG. 1, RT is a calling terminal, LF1 to LF5 are called terminals, and SN.
1 to SN4 are two-layer sub-networks each having a plurality of lower sub-networks connected to each other.
The layer sub-networks SN1 and SN2 are connected by a link L6, and the destination terminal LF4 is connected to the two-layer sub-network SN2 via the link L4.

The two-layer sub-networks SN1-SN
3 and between SN3 and SN4 are link L, respectively.
7, L8, and the destination terminal LF5 is connected to the two-layer subnetwork SN4 via the link L5.
Each of the two-layer sub-networks SN1 to SN4 has a two-layer subnet manager S that manages these sub-networks.
M1 to SM4 are arranged.

In the two-layer subnetwork SN1, S
N11 to SN13 are first-layer sub-networks located below the sub-network SN1, and the first-layer sub-networks SN11 and SN12 are connected by a link L11. In addition, the 1st layer subnetwork SN12-SN
13 are connected by a link L12, and the destination terminal L
F3 connects to layer 1 subnetwork SN1 via link L3
Connected to 3.

Each one-layer subnetwork SN11 to SN1
3 is provided with 1-layer subnet managers SM11 to SM13 that manage these networks. In the 1st-layer subnetwork SN12, N21 to N24 actually accommodate links between subnetworks and terminals, and bandwidth reservation for a predetermined link is made in response to a bandwidth reservation / release request from the upper subnet manager or each terminal. / It is a switching node that performs release.

A link L2 is provided between the switching nodes N21 and N22.
1 is also connected, and similarly between N21 and N23, N21-
The links N22 and N22-N23 are connected by links L22, L23, and L24, respectively.
In the first layer sub-networks SN11 and SN13, as in the first layer sub-network SN12, there are a plurality of switching nodes connected to each other by links.

The two-layer sub-networks SN2 to SN
Also in 4, like the two-layer subnetwork SN1,
There are multiple one-layer sub-networks interconnected by links. The subnet manager and each switching node in each layer are connected to each other via a predetermined communication line, and commonly use the management information of the sub-network or switching node in the same layer.

Further, the subnet managers in the vertically adjacent layers and between the subnet manager and the switching node are also connected via a predetermined communication line. Therefore, as a control message for call processing, messages such as a bandwidth reservation / release request of the link and a bandwidth reservation request / release response to the request are directly exchanged.

Further, the link allocatable bandwidth amount calculated in the switching node is directly notified to the management source subnet manager which manages each link, and the link usage rate of each link is grasped in real time. As a result, each subnet manager knows the connection status between the sub-networks of the hierarchy to which it is connected, and the connection that is most likely to succeed in bandwidth reservation on each link for various MC connection configurations. The route is constantly updated and retained.

FIG. 2 is a block diagram showing a subnet manager and a switching node, where (a) shows the subnet manager and (b) shows the switching node. Hereinafter, as a subnet manager, the first layer subnetwork SN12
The layer 1 subnet manager SM12 that manages the network is taken as an example, and the layer 1 subnetwork SN12 is used as an exchange node.
The exchange node N21 that configures the above will be described as an example.

In FIG. 2A, reference numeral 12 is a switching node in the layer 1 subnetwork SN12 managed by itself, and switching nodes (N22, N23) accommodating terminals, and switching adjacent to other subnetworks. Node (N2
, N23, N24), one to one for each switching node
2 is an intra-subnet routing table holding unit that holds an intra-subnet routing table that sequentially stores the optimum route in the VC connection.

Reference numeral 13 denotes a peer 1-layer sub-network connected in the same layer, here, a 1-layer sub-network that is the same as the self in the same 2-layer sub-network, and a 1-layer including an exchange node accommodating terminals. Sub-networks (SN11 to SN13) and 1-layer sub-network (SN12) adjacent to other 2-layer sub-networks
Is an inter-subnet routing table holding unit that holds an inter-subnet routing table that sequentially stores optimum routes in a one-to-one VC connection for each 1-layer sub-network.

Reference numeral 11 denotes switching nodes N21 to N24 in the sub-network SN12 which is managed by itself based on the notification of the link assignable bandwidth amount from each switching node,
For each switching node that accommodates links to terminals and other sub-networks, a route group that connects the switching nodes in a one-to-one relationship is sequentially extracted according to the number of transit nodes and the link allocatable bandwidth, and the subnet It is a table management unit for sequentially updating and storing in the inter-routing table 12.

Further, the table management unit 11 determines the link allocatable bandwidth amount of the boundary link with the other 1-layer sub-networks SN11 and SN13, the 1-layer subnet managers SM11 and S which are connected to the same layer and are on the same level.
By mutually exchanging with M13, for each 1-layer sub-network that accommodates links with terminals and other 2-layer sub-networks, the number of route nodes and the link-allocatable bandwidth for the route group that connects them one-to-one Optimal routes are sequentially extracted according to the amount, and routing table between subnets 1
3 is updated and stored in order.

Reference numeral 16 denotes the number of transit nodes for all MC connection modes in which one of the self-coordinated one-layer sub-networks SM11 to SM13 connected in the same hierarchy is MC-connected with the originating and terminating side end points. Is an MC table creation unit that creates and holds a routing table consisting of one or more MC connection routes with the smallest number.

The originating side end point and the destination side end point indicate each end point of the MC connection route having a tree structure, that is, a subnetwork or a switching node accommodating a boundary link with a terminal or another subnetwork. Especially,
The originating-side endpoint is the endpoint closest to the originating terminal on the MC connection route, and the destination-side endpoint is the endpoint closest to each destination terminal on the MC-connection route.

In the case of the subnet manager SM12, since the sub-network SN12 managed by itself is composed of switching nodes, these switching nodes N
A routing table for MC connection between 21 and N24 is also created and held. Note that these routing tables are only available when the subnetwork configuration is changed.
It is created by the MC table creation unit 16.

In response to a predetermined routing registration request, 17 is an MC table creating section 1 based on end point information and the like indicating the calling side and called side necessary for creating the routing table.
6 reads out the corresponding routing table, and uses the MC table management unit 18 to read the routing table.
The corresponding routing table is registered in the routing table holding unit 19, and the corresponding routing table is stored in the MC routing table holding unit 19 in response to a predetermined routing table deletion request.
It is an MC routing table registration / deletion unit to be deleted from.

The MC table management unit 18 sets each routing table in the MC routing table holding unit 19 registered by the MC routing table registration / deletion unit 16 based on the notification of the link allocatable bandwidth amount from each switching node. , Sorting is always performed in descending order of allocatable bandwidth. Therefore, in each routing table, the respective MC connection routes stored respectively are sorted and held sequentially in the descending order of the link assignable bandwidth amount.

In response to a predetermined MC connection request, 14 acquires from the MC routing table holding unit 19 the MC connection route information having the largest reservable bandwidth amount corresponding to the end point information, and the predetermined MC connection route is configured. Link of
A request for path setting is made by bandwidth reservation to the sub-network or switching node, and this MC connection route information is stored in the set route holding unit 15, while a predetermined M
In response to the C release request, a path setting / release request unit that requests the path release by band release to a predetermined link, sub-network or switching node based on the MC connection route information stored in the set route holding unit 15. Is.

The MC routing table holding unit 19
As a result of performing the MC connection process based on the MC connection route acquired from the above, if the bandwidth reservation fails in all the connection routes, the path setting / release request unit 14 determines the same in the MC routing table holding unit 19. The MC connection route having the next largest reservable bandwidth amount is acquired from the routing table, and the MC connection process is repeatedly executed. Also, this MC
The number of times the connection process is repeated is defined by the communication quality parameter (QOS) included in the bandwidth reservation request.

Further, the path setting / release requesting section 14 responds to a predetermined one-to-one connection request with 1 corresponding to the end point information.
The one-to-one connection route information is acquired from the intra-subnet routing table holding unit 12 or the inter-subnet routing table holding unit 13, and based on the one-to-one connection route information, bandwidth reservation is performed for a predetermined link, sub-network or switching node. While requesting the path setting, the one-to-one connection route information is stored in the set route holding unit 15, while the one-to-one stored in the set route holding unit 15 in response to a predetermined one-to-one release request. A path release request is made to a predetermined link, sub-network or switching node based on the connection route information.

Further, in the path setting / release request section 14,
The call identifier included in each MC connection request or one-to-one connection request is inherited and notified to each path setting request. Also, when the MC connection route information and the one-to-one connection route information are stored in the set route holding unit 15, this call identifier is inherited and stored. It should be noted that this call identifier is uniquely assigned to the entire network by the subnet manager that first sends the MC connection request, that is, the registered subnet manager.

In the above description, the subnet manager that manages the first layer sub-network consisting of the switching nodes has been taken as an example, but a subnet manager that manages the sub-network consisting of the sub-network groups, for example, the second-layer subnet managers SM1 to SM4. However, it has the same configuration as described above. However, the switching node described above is replaced by a lower subnetwork.

In FIG. 2B, 21 is a link usage rate holding unit that holds the usage rate of each link connected to the switching node, and 22 is the link usage rate held in the link usage rate 21 and its link usage rate. It is a comparison and notification unit that notifies the link source allocatable band amount calculated from the link free band and the cell (or packet) discard rate to the management source subnet manager of each link at a predetermined timing.

Reference numeral 23 is the same MC call for judging whether or not each bandwidth reservation / release request is for the same MC connection call based on the call identifier included in the bandwidth reservation / release request from the upper subnet manager. It is a judgment unit. By this determination, overlapping band reservation / release processing by the same MC connection call for the same link is avoided.

Each switching node has a call control management function for a link to be accommodated and a function for exchanging data flowing on the link, like a general ATM switch or packet switch. In particular, in response to a bandwidth reservation request for a predetermined link accommodated by itself, in the free bandwidth on the link, while securing the requested amount of bandwidth, in response to a bandwidth release request for a predetermined link accommodated by itself, The bandwidth used for the requested path is released.

Next, with reference to FIGS. 3 and 4, as an operation of the present invention, an MC connection process for connecting the calling terminal RT and the called terminals LF1 to LF5 by MC will be described. FIG. 3 is a sequence diagram showing MC connection processing between two-layer sub-networks (second layer) by the registered subnet manager, and FIG. 4 is a flowchart showing MC connection processing between each sub-network (each layer).

First, the calling terminal RT registers a MC connection route for connecting the calling and called terminals with MC prior to the actual MC connection request. Therefore, a predetermined MC routing including address information indicating these terminals is registered. A registration request R30 is sent. The MC routing registration request R30 is received by a predetermined switching node N11 (not shown) in the sub-network SN11 accommodating the calling terminal RT, and these address information are analyzed.

The calling terminal and each called terminal have the following addresses, respectively. Originating terminal RT = 1; 11; 11; RT destination terminal LF1 = 1; 12; 22; LF1 destination terminal LF2 = 1; 12; 23; LF2 destination terminal LF3 = 1; 13; 31; LF3 destination terminal LF4 = 2; 14; 44; LF4 destination terminal LF5 = 4; 11; 15; LF5

Each address is an identifier (hereinafter, ID) for identifying each sub-network and switching node N11.
1), the two-layer network shown in FIG. 1 shows the network configuration in the order of the second-layer subnetwork ID; the first-layer subnetwork ID; the exchange node ID; and the terminal ID. Therefore, it can be seen that, for example, the destination terminal LF2 is accommodated in the switching node N23 in the first-layer subnetwork SM12 of the second-layer subnetwork SM1 by its address.

Upon receiving the MC routing registration request R30, the exchange node N11 receives from the addresses of these calling and receiving terminals,
A sub-network that is one layer lower than the sub-network of the lowest hierarchy that accommodates all terminals and that accommodates the originating terminal RT, here, the subnet manager SM1 of the sub-network SN1 is selected and received as the registered subnet manager. MC routing registration request R3
0 is sent as the MC routing registration request R31.

The registered subnet manager SM1 is the MC
In response to receiving the routing registration request R31, the calling terminal RT
And the destination terminals LF1 to LF5 as the destination endpoints, the registration process of the MC connection route is started. First, the MC routing table registration / deletion unit 17 (see FIG. 2) of the registered subnet manager SM1 is operated by the MC table creation unit 16
Among a large number of MC connection routes created in advance, the MC connection route having the originating terminal RT as the originating end point and each of the destination terminals LF1 to LF5 as the destination end point, and having the fewest transit nodes A predetermined number of routes are registered in the MC table management unit 18.

The MC table management unit 18 registers the predetermined number of MC connection routes registered by the MC routing registration / deletion unit 17 in a predetermined routing table. After registration, calculate the link allocatable bandwidth for each MC connection route based on the link utilization of each link notified from each switching node included in these MC connection routes, and calculate the link allocatable Based on the bandwidth amount, the MC connection routes in this routing table are rearranged (sorting).

Therefore, at the timing when the link utilization rate of each link constituting each MC connection route is updated, a new link assignable bandwidth amount is calculated, and the MC connection routes are sorted (sorting) in the MC routing table. ) Is performed, and the one having the largest link assignable bandwidth amount is held in the MC routing table holding unit 19. As a result, the MC routing table holding unit 19 always extracts and prepares the optimum MC connection route having the smallest number of transit nodes and the largest link allocatable bandwidth amount before the actual MC connection request. Becomes

After such routing registration processing is performed, the registered subnet manager SM1 returns an MC routing registration request response A31 as a response corresponding to the MC routing registration request R31. Thereby, this M
The C routing registration request response R31 is returned to the calling terminal RT as an MC routing registration request response R30 via the switching node N11 that accommodates the calling terminal RT, and the calling terminal RT
Confirms that the MC connection route has been registered.

After that, the calling terminal RT performs data communication with its own RT and the addresses of the destination terminals LF1 to LF5 in order to actually transmit the data to the destination terminals LF1 to LF5, if necessary. The MC connection request S32 including the required bandwidth amount is transmitted. In response to this, the switching node N11 accommodating the calling terminal RT first makes a reservation for the amount of band requested by the calling terminal RT with respect to the link L0 connecting the calling terminal RT by the band reservation request S33.

After the success of bandwidth reservation is confirmed by the bandwidth reservation request response C33 to the bandwidth reservation request S32,
From the switching node accommodating the calling terminal RT to the registered subnet manager, namely the registered subnet manager SM1
To the MC connection request R34. If the bandwidth reservation of the link L0 fails, the fact is notified to the calling terminal RT and the process is terminated.

In response to the MC connection request R34, the registered subnet manager SM1 determines a unique call identifier for the entire network to identify the MC connection call, and starts the MC connection processing as shown in FIG. . Or later,
This call identifier will be successively inherited and stored in all call control messages related to this MC connection call,
It will be distinguished from other connection calls.

First, the path setting / releasing request unit 14 uses the MC
The optimum MC connection route is acquired from the routing table holding unit 19 as an MC tree (MC Tree) (step 40). This MC tree shows an MC connection route between sub-networks or switching nodes in the hierarchy in which the subnet manager exists by a tree structure (tree structure), and the registered subnet manager SM1 managing the sub-network SN1 is shown in FIG. MC as shown in (a)
Get the tree.

In the MC tree of FIG. 8A, the root (Ro
ot), that is, from the sub-network SN1 that is the originating end point, to the leaf (that is, the destination terminal LF that is the destination end point)
1 to LF3 are connected, and sub-network SN
M to connect the destination terminal LF4 via 2 and further connect the destination terminal LF5 via the sub-networks SN3 and SN4
The C connection route is shown.

Subsequently, the registered subnet manager SM1
Is a registered subnet manager (step 41: YES), the path setup / release request unit 14
Based on this MC tree, a bandwidth reservation request S35 is sent to the links L1 to L5 connecting the destination terminals LF1 to LF5 to the individual accommodation nodes and the links L6 to L8 connecting the two-layer sub-networks, respectively. (Step 41Y).

In response to this, the sub-networks and the destination terminals at both ends of each of these links reserve the requested bandwidth and return a bandwidth reservation request response C35. The registered subnet manager SM1 receives the bandwidth reservation request response C35.
Is received, a sub-tree (Sub Tree) indicating the success or failure of the requested bandwidth reservation is generated based on the results indicated by these responses (step 42), and the bandwidth reservation request response confirmation A35 for the link for which the bandwidth reservation is successful. Will be returned.

FIG. 8B shows a subtree created by the registered subnet manager SM1. In this case, since the bandwidth reservation has failed (NG) in the link L7 connecting the sub-networks SN1 and SN3, FIG.
The route connecting the destination terminal LF5 via the sub-networks SN3, SN4 is deleted from the original MC tree shown in (a).

Next, the registered subnet manager SM1
Is the MC in each subnetwork that makes up the subtree
Make a connection request. First, it is judged whether or not there is a connection failure route in the route connection request for the destination terminal accommodating link and the inter-subnetwork link described above (step 43), and if all are successful (step 43: NO), a subtree is constructed. Requesting MC connection in each subnetwork (step 43)
N).

Further, as described above, when the connection fails in any route (step 43: YES), for each link constituting only the route in which the connection fails,
By sending the band release request R36, the already reserved band is released. In this case, since the bandwidth reservation of the link L7 has failed, the connection route via this link L7, here the link L8 configuring the connection route from the subnetwork SN1 to the subnetwork SN4 accommodating the destination terminal LF5 To be released.

Next, the registered subnet manager SM1
Attempts to establish a connection by a one-to-one connection process that is separate from the MC connection process in order to relieve between the sub-networks released due to the connection failure. That is, the sub-networks SN1 and SN3 released due to the connection failure are connected 1: 1.
Make a one-to-one connection request.

In this case, the one-to-one connection request is sent to itself, and in response to the reception, the registered subnet manager SM1 sends the path setup / release request section 15
Thus, the one-to-one connection process is performed. In order to establish a connection between sub-networks, the path setup / release request unit 15 first reads out the optimum connection route corresponding to the request from the inter-subnet routing table holding unit 13, and connects between the sub-networks forming the connection route. Request bandwidth reservation for the link.

Then, in response to the success of the bandwidth reservation request, the one-to-one connection request in each sub-network forming the connection route is sent to the subnet manager of each sub-network. It should be noted that in the connection request for connecting between the sub-networks and the sub-networks, the call identifier indicating the original MC connection included in the received one-to-one connection request is inherited and stored.

In this way, the one-to-one connection processing is repeatedly executed by each subnet manager that has received the one-to-one connection request in each sub-network, as described above.
The connection between the sub-networks that failed in the MC connection processing, in the above example the connection between the sub-networks SN1 to SN4, is
Attempted by a one-to-one connection separate from the connection. Further, the result of this one-to-one connection processing is returned to the sub-network SM1 which is the request source.

In parallel with this one-to-one connection request, the registered subnet manager SM1 confirms the connection routes that have been successfully connected on the basis of the above-mentioned subtree, and the lower sub-networks that compose these connection routes, here SM1,
An MC connection request R37 requesting MC connection in the sub-network is sent to the SM2. In response to this, the SM1 and SM2 perform the MC connection processing in the sub-network as described later, and the connection result is returned by the MC connection request response C37.

The registered subnet manager SM1 receives all the result responses of these MC connection request responses C37,
Sub2 Tree (Sub2 Tree)
) Is generated (step 45), and the registered subnet managers SM1 and SM with which the MC connection has succeeded completely or partially.
2, the bandwidth reservation request response confirmation A37 is returned.
In this case, 1 between the sub-networks SN1 and SN4
One-to-one connection and MC in subnetwork SN1
Since a part of the connections has failed, a sub-subtree as shown in FIG. 8C is generated.

Next, the registered subnet manager SM1
Judges whether or not there is a route for which MC connection has failed in the MC connection request for the sub-network based on the sub-subtree (step 46). Here, if there is a connection failure route (step 46: YES), the MC connection route in the sub-network that constitutes only the connection failure route is released as described above (step 46N).

Then, a one-to-one connection process for connecting the second layer sub-network which is the destination end point of the connection failure route and the second layer sub-network which is the originating end point is executed (step 47). However, here, since both the originating side and the terminating side end points are the sub-network SN1,
One-to-one connection processing is not performed.

Next, the registered subnet manager SM1
Is based on the sub-subtree and the one-to-one connection result,
Generate a route connection result for the requested MC connection request. Here, since it is the registered subnet manager SM1 (step 48: YES), the band release request R3
8, the destination terminal that failed to connect, in this case the destination terminal LF
Links L3 and L5 accommodating 3 and LF5 are released, and the end of release is notified by the band release request response C38.

In this way, when there is a destination terminal that has failed to connect, the destination terminal accommodation link is released, and after the release is confirmed, the registered subnet manager SM1
Requests the result of all MC connections from the calling terminal RT
To the MC connection request response C34 (step 49). Further, the MC connection request response confirmation A35 'is sent to the links L1, L2, L4 accommodating the destination terminals that have been successfully connected.

This MC connection request response C34 is the calling terminal R
MC connection request response C via the switching node accommodating T
It is notified to the calling terminal RT as 32. The MC connection request C32 is received by the calling terminal RT, the destination terminals LF1, LF2, LF4 for which the MC connection is successful are confirmed, the MC connection request response confirmation A32 is sent, and the calling terminal RT is sent.
The MC connection request response confirmation A34 is returned to the registered subnet manager SM1 via the switching node accommodating the.

As a result, the calling terminal RT and each called terminal LF
A series of MC connection processing for MC connection of 1, LF2, LF4 is completed, and data transmission from the calling terminal RT to these called terminals is started.

Next, with reference to FIG. 5, the MC connection processing between the first layer sub-networks (first layer) will be described. FIG. 5 is a sequence diagram showing MC connection processing between the first layer sub-networks (first layer). Here, SM11 performs MC connection processing within sub-network SN1 in response to an MC connection request from registered subnet manager SM1. The case of performing will be described as an example.

In response to the MC connection request R37 (see FIG. 3), the registered subnet manager SM1 selects any one-layer subnet manager in the subnetwork SN1 and sends the MC connection request S50. For example, when the subnet manager SM11 is selected and the MC connection request R50 is sent, the subnet manager SM11 executes the same MC connection process (see FIG. 4) as the registered subnet manager SM1 described above.

First, an MC tree as shown in FIG. 8D is obtained corresponding to the MC connection route requested by the MC connection request R50 (step 40). In this case, the originating side endpoint (Root) is the sub-network SN11 closest to the originating terminal on the MC connection route, and the destination side endpoint (Leef) is also the closest sub-network SN12, S to the destination terminal.
It becomes N13. Next, since it is not the registered subnet manager (step 41: NO), the bandwidth reservation request S51 is sent to the respective inter-subnetwork links L11, L12 forming the MC tree (step 41N).

In response to this, a subtree as shown in FIG. 8E is generated based on the returned bandwidth reservation request response C51 (step 42). Here, if the bandwidth reservation is successful, the bandwidth reservation request response confirmation A51 is sent to these links, and there is no connection failure (step 43: NO). Therefore, the subnet manager of each subnetwork forming the subtree. MC connection request R52 in each sub-network to SM11 to SM13
Is transmitted (step 43N).

Then, each subnet manager SM11
Receive MC connection request response C52 from SM13 and generate sub-subtree (step 45). Here, if the MC connection fails (NG) in the sub-network SN13, a sub-subtree as shown in FIG. 8F is generated. Therefore, the route connection in the subnetwork SN13 has failed (step 46: YE
S), the connection route via this sub-network SN13, here the link L12, is released by the band release request R53.

In response to this, after confirming the returned bandwidth release request response C53, the connection failure route, here, the subnetwork SN11 which is the originating end point and the subnetwork SN13 which is the destination end point, are connected. A one-to-one connection process is executed (step 47). One to one in this case
The connection request is sent to itself in the same manner as described above, and a predetermined one-to-one connection process is executed.

Next, the subnet manager SM11
Generate a route connection result for the requested MC connection request based on the result of the MC connection process and the one-to-one connection,
This is sent back to the requesting registered subnet manager SM1 by the MC connection request response C50, and the series of MC connection processing within the sub-network is ended. For example, one-to-one between the sub-networks SN11 and SN13
When the connection fails, the root connection result has a tree structure as shown in FIG.

Next, with reference to FIGS. 6 and 7, the MC connection processing between the exchange nodes (within the one-layer subnetwork) will be described. FIG. 6 is a sequence diagram showing MC connection processing between switching nodes (within the 1st layer subnetwork), and FIG. 7 is a flowchart showing MC connection processing between switching nodes (within the 1st layer subnetwork). An example will be described in which the SM 12 performs the MC connection process in the sub-network SN12 in response to the MC connection request from the SM 11.

In response to the MC connection request R52 (see FIG. 5), the subnet manager SM12 carries out the MC connection processing as shown in FIG. First, the MC tree corresponding to the received MC connection request R52 is acquired (step 70).
I do. In this case, since the originating end point is the exchange node N21 and the destination end point is the exchange nodes N22, N23, N24, the MC tree is as shown in FIG. 8 (g).

Next, the subnet manager SM12
Since it is not the registered subnet manager (step 71: NO), based on this MC tree, in order to connect the routes between the respective switching nodes, the corresponding links L2
A bandwidth reservation request S60 is sent to 1 to L23 (step 71N). The subnet manager SM12
However, if it is a registered subnet manager, a bandwidth reservation request is sent to the link connecting each destination terminal in parallel with the bandwidth reservation request to these inter-exchange node links (step 71Y).

When actually reserving the bandwidth of the link in response to the bandwidth reservation request, the switching node is reserved by the same MC call determination unit 33 by the same call as the connection call indicated by the call identifier included in the bandwidth reservation request. It is determined whether there is a reserved bandwidth. Here, if there is a bandwidth reservation reserved by the same call, a new bandwidth is not reserved for the link and the already reserved bandwidth is used. Keep it. This avoids duplication of bandwidth reservation due to the same call on the same link, and the resources of the entire network are effectively used.

Subsequently, the subnet manager SM12
The bandwidth reservation request response C60 returned in response to the bandwidth reservation request S60 is received and a subtree is generated (step 7).
2). In this case, since the bandwidth reservation has failed on the link L22, the subtree has a configuration as shown in FIG.

Since the subnet manager SM12 sends a bandwidth reservation request response confirmation A60 to the links L21 and L23 for which the bandwidth reservation has succeeded, there is a connection failure (step 73: YES). The constituent links are released (step 73Y). In this case, there is no corresponding link.

Subsequently, the originating side end point and the terminating side end point of the connection failure route, here, the one-to-one connection between the switching nodes N21 and N23.
A connection request is made (step 74). In response to this request, the subnet manager SM12 carries out a one-to-one connection process connecting the switching nodes N21 and N23, as described above.

After that, the subnet manager SM12
Is not a registered subnet manager (step 75: NO), the root connection result is returned by the MC connection request response C52 based on the above-mentioned subtree (step 76), and the series of MC connection processing ends. If the subnet manager SM12 is a registered subnet manager (step 75: YES),
After the link accommodating the destination terminal that failed in connection is released (step 75Y), the MC connection request response C52 is returned.

In this way, a hierarchical network is constructed from a plurality of switching nodes or sub-networks, and in each layer, MC connection route information (MC tree) for connecting the originating and terminating points in that layer in response to a predetermined MC connection request. )
Based on the above, bandwidth reservation is performed in parallel for each inter-subnetwork link that constitutes the MC connection route, and MC connection in the sub-network is paralleled to each lower sub-network on the connection route for which the bandwidth reservation is successful. It is the one that has been specifically requested.

Therefore, bandwidth reservation is performed collectively for all links connecting sub-networks in each layer, and MC connection processing within each sub-network is performed collectively. As described above, it is possible to dramatically reduce the time required for the multicast connection processing, as compared with the case where each destination terminal is increased or decreased by one party.

Further, as an MC connection route (MC tree) that connects the originating and terminating endpoints in each layer, an MC connection route is created in advance for all endpoint information, and the MC with the smallest number of transit nodes responds to the MC connection request. Since the connection route is selected, it is possible to configure the MC connection with the minimum number of links and switching nodes.
It is possible to effectively use the resources of the entire network and reduce the time required to select the optimum MC connection route.

Further, based on the latest link utilization rate notified from each switching node, the reservable bandwidth amount of each MC connection route is sequentially calculated, and the MC connection route having the most reservable bandwidth amount is selected. Therefore, the possibility of success is increased when the bandwidth is actually reserved for each link, and the call loss rate for the MC connection request can be reduced.

Further, when the bandwidth reservation fails, the originating side end point and the terminating side end point of the connection route are retried by a one-to-one connection request, so that the call loss rate for the MC connection request is reduced. It becomes possible. Further, since a call identifier for identifying each MC connection call is provided so as to identify the one-to-one connection call generated from that MC connection call, bandwidth reservation by the same MC connection call on the same link is made. Duplication can be avoided and network resources can be effectively used.

Prior to the MC connection request, the calling terminal R
A routing registration request R30 is sent from T, and the corresponding subnet manager SM1 responds to this request by the corresponding MC.
Since the sorting (sorting) of the routing table including the connection route group is started, thereafter, the MC connection request R is issued from the calling terminal RT as needed for data transmission.
When 34 is sent, the optimum MC connection route can be quickly selected, and the time required for the MC connection process can be shortened.

Next, referring to FIG. 9 and FIG. 10, as the operation of the present invention, the calling terminal RT and the called terminals LF1, LF
2, MC release processing when releasing the MC connection with the LF 4 will be described. FIG. 9 is a sequence diagram showing an MC release process between two-layer sub-networks (second layer) by the registered subnet manager, and FIG. 10 is a flowchart showing an MC release process between each sub-network.

Upon completion of communication with each destination terminal, the calling terminal R
T sends an MC release request R90 to the switching node N11 (not shown) that accommodates the calling terminal RT. This M
The C release request R90 is sent to the registered subnet manager SM1 as an MC release request R91 via the switching node. In response, the registered subnet manager SM1
The path setting / release requesting unit 14 acquires the MC connection route information stored in the setting route holding unit 15 during the MC connection processing (step 100).

Subsequently, the registered subnet manager SM1
Is a registered subnet manager (step 101: YES), the links L1, L2 connecting the destination terminals LF1, LF2, LF4 are requested by the bandwidth release request S92.
The bandwidth of the link L6 that connects the L4 and the two-layer subnetwork that forms the MC connection route is released, and in parallel with this, the connection route in the two-layer subnetwork that forms the MC connection route is issued by the bandwidth release request R93. Is requested (step 101Y).

In response to this, the bandwidth is released in each link and the lower layer sub-network, and the responses are returned by the bandwidth release request responses C92 and C93, respectively.
The registered subnet manager SM1 confirms all these responses (step 102: YES), and then the calling terminal R
A band release request response C91 is returned to the switching node N11 accommodating T (step 103). This allows
The band release request response C90 is returned to the calling terminal RT via this exchange node, and the band release processing of all MC connection routes is completed.

In this way, in response to the MC release request requested in response to the end of data communication at the calling terminal RT,
The MC connection with each destination terminal is released, and the network resources are used for other communication. Therefore, when a new data transmission request is generated in the calling terminal RT, an MC connection request is sent from the calling terminal RT to the network, and the MC connection processing as described above is performed.

Further, a routing deletion request R94 is sent from the calling terminal RT in response to the end of all data communication. This routing deletion request R94 is transferred to the registered subnet manager SM1 as the routing deletion request R95 via the switching node N11 which accommodates the calling terminal RT. In response, the registered subnet manager SM
The MC routing table registration / deletion unit 17 of 1
The routing table registered in the routing table holding unit 19 is deleted.

As a result, the predetermined routing table registered by the routing registration request R30 is deleted from the MC routing table holding unit 19 prior to the MC connection processing. Therefore, as a preparation for the MC connection request, the rearrangement (sorting) of the routing tables by the MC table management unit 18 that has been sequentially performed is stopped.

Next, with reference to FIG. 11, the process of releasing the MC connection route between the first layer sub-networks (first layer) will be described. FIG. 11 shows between the first-layer sub-networks (first
It is a sequence diagram which shows the MC release process in (layer).
The flowchart is shown in FIG.

The subnet manager SM1 selects any one layer subnet manager in the two layer subnetwork SN1, for example, the subnet manager SM11,
MC release request R110 is transmitted. In response to this, the subnet manager SM11 acquires the set route information as described above (step 100).

Here, since it is not the registered subnet manager (step 101: NO), the bandwidth release request S
111 releases the bandwidth of the link L11 that connects between the first-layer sub-networks that form the MC connection route, and in parallel with this, the MC release request R112 causes M
C Releases the connection route in the 1st layer sub-network forming the connection route (step 101N).

In response to this, band release is performed in each link and lower layer sub-network, and the responses are returned by band release request response C111 and MC band release request response C112, respectively. After confirming all these responses (step 102: YES), the subnet manager SM11 returns an MC release request response C110 to the higher-level registered subnet manager SM1 (step 103). As a result, the band releasing process for all MC connection routes in the two-layer sub-network is completed.

Next, with reference to FIGS. 12 and 13, the process of releasing the MC connection route between the switching nodes (within the first layer sub-network) will be described. FIG. 12 is a sequence diagram showing MC release processing between switching nodes (within the 1st layer subnetwork), and FIG. 13 is a flowchart showing MC release processing between switching nodes (within the 1st layer subnetwork).

In response to the MC release request R112 (see FIG. 11), the subnet manager SM12 acquires the MC connection route information as described above (step 130). Here, since it is not the registered subnet manager (step 131: NO), M is requested by the bandwidth release request S120.
C Each link L connecting the switching nodes forming the connection route
21 and L23 are requested to be released (step 131N).

If the subnet manager SM12 is a registered subnet manager (step 13
1: YES), the link accommodating each destination terminal is released concurrently with the release of the inter-switch node route (step 131Y). In response to this, the bandwidth is released in each link, and the response is the bandwidth release request response C, respectively.
Returned by 120.

After releasing the inter-switch node route, the subnet manager SM12 confirms all these responses (step 132: YES), and then releases the MC release request R1.
The band release request response C112 is returned to the subnet manager SM11 that is the request source of the 12 (step 1
33). As a result, the band release processing for all MC connection routes in the first layer sub-network is completed.

The subnet manager of each layer is M
In response to the reception of the C release request, the set route holding unit 15 searches for one-to-one connection route information having the same call identifier as the call identifier. Here, when the one-to-one connection route information having the same call identifier is extracted, the one-to-one release processing is performed in parallel with the MC release processing of the lower subnetwork and based on the one-to-one connection information. carry out.

As a result, similar to the one-to-one connection processing, the one-to-one release processing is sequentially executed in parallel in each layer. In each switching node, the same MC call determination unit 33 determines the call identifier in response to the bandwidth release request, and if the bandwidth to be released is not shared by the same connection call, the bandwidth is released. When the shared bandwidth is shared, it is not released immediately even if it is a release request from the same connection call. Release that bandwidth accordingly.

As described above, during the MC connection processing, the MC connection route information is held for each layer, and the MC connection route is constructed based on the held MC connection route information in response to the MC release request. The bandwidth release of the links between the sub-networks is performed in parallel, and the MC release in the sub-network is requested in parallel to each lower sub-network on the MC connection route.

Further, the one-to-one connection having the same call identifier as the call identifier included in the bandwidth release request is also subjected to the one-to-one release processing in parallel with the MC release processing. Therefore, all links connecting sub-networks in each layer, MC release processing in each sub-network, and one-to-one release processing are collectively performed, and the time required for the multicast release processing is dramatically increased. It can be shortened.

Further, in response to the end of the data communication, the calling terminal R
Since the routing subnet delete request is sent from T, and in response to this, the registered subnet manager SM1 finishes the rearrangement of the routing table, which was performed as a preparation for the MC connection processing, the predetermined originating side and destination side endpoints are set. The MC connection route connecting the
The processing of sequentially rearranging is stopped, and the processing load on the registered subnet manager SM1 is reduced.

[0113]

As described above, the present invention forms a hierarchical network from a plurality of switching nodes or sub-networks, and in each layer, each sub-network in that layer is responsive to a predetermined multicast connection request. Based on the multicast connection route to be connected, bandwidth reservations for the links between sub-networks that make up the multicast connection route are performed in parallel, and sub-networks are created for each sub-network on the connection route for which the bandwidth reservation was successful. It is designed to request multicast connections in parallel.

Therefore, bandwidth reservation is performed collectively for all links connecting sub-networks in each layer, and multicast connection processing within each sub-network is performed collectively. As described above, it is possible to dramatically reduce the time required for the multicast connection processing, as compared with the case where each destination terminal is increased or decreased by one party.

Further, since the multicast connection route with the smallest number of transit nodes is selected as the multicast connection route in each layer, it becomes possible to configure the multicast connection with the minimum number of links and exchange nodes, and the entire network. It becomes possible to effectively use the resources of.

Further, as the multicast connection route in each layer, the multicast connection route having the smallest number of transit nodes and the largest reservable bandwidth of each link constituting the multicast connection route is selected. By doing so, it is possible to effectively use the resources of the entire network, and the possibility of success is increased when bandwidth reservation is actually performed for each link, and the call loss rate for multicast connection requests is reduced. It becomes possible.

When the bandwidth reservation fails, the connection is tried again with the one-to-one connection request corresponding to the failed connection route, so that the call loss rate for the multicast connection request can be reduced. Become. Further, since a call identifier for identifying each multicast connection call is provided so as to identify the one-to-one connection call generated from the call, duplication of bandwidth reservation due to the same multicast connection call on the same link. It is possible to avoid it, and it is possible to effectively use network resources.

In this way, at the end of the multicast connection, the multicast connection route is held for each layer, and the bandwidth of each inter-subnetwork link that constitutes the held multicast connection route in response to the multicast release request. Release in parallel,
Multicast release within a subnetwork is requested in parallel to each subnetwork on the multicast connection route, so all links connecting subnetworks in each layer and multicast release processing within each subnetwork Will be performed collectively, and the time required for the multicast release processing can be dramatically reduced.

Further, in the layer immediately below the layer in which the calling terminal and all the called terminals are accommodated in the same sub-network, in response to a predetermined routing registration request from the calling terminal,
Among the corresponding multicast connection routes, the multicast connection route with the smallest number of sub-networks or switching nodes to pass through is started to be sequentially rearranged in descending order of reservable bandwidth for each link. , When an MC connection request R34 is sent from the calling terminal RT according to the need for data transmission, it becomes possible to quickly select an optimum MC connection route.
It is possible to reduce the time required for the C connection process.
Further, since the rearrangement processing of the multicast connection routes is stopped in response to a predetermined routing deletion request from the calling terminal, each of the MC connection routes connecting the originating and terminating end points can be reserved thereafter. The processing of sequentially rearranging is stopped depending on the bandwidth amount, and the processing load on the registered subnet manager SM1 is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a hierarchical network system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a subnet manager and a switching node.

FIG. 3 is a sequence diagram showing an MC connection process between two layer sub-networks.

FIG. 4 is a flowchart showing an MC connection process between sub-networks.

FIG. 5 is a sequence diagram showing an MC connection process between layer 1 sub-networks.

FIG. 6 is a sequence diagram showing an MC connection process between switching nodes.

FIG. 7 is a flowchart showing an MC connection process between switching nodes.

FIG. 8 is an explanatory diagram showing a transition example of an MC connection route.

FIG. 9 is a sequence diagram showing MC release processing between two-layer sub-networks.

FIG. 10 is a flowchart showing an MC release process between sub-networks.

FIG. 11 is a sequence diagram showing an MC release process between layer 1 sub-networks.

FIG. 12 is a sequence diagram showing MC release processing between switching nodes.

FIG. 13 is a flowchart showing an MC release process between switching nodes.

[Explanation of symbols]

RT: calling terminal, LF1 to LF5 ... destination terminal, SN1 to SN
4 ... 2-layer subnetwork, SM1-SM4 ... 2-layer subnet manager, SN11-SN13 ... 1-layer subnetwork, SM11-SM13 ... 1-layer subnet manager, N21-N24 ... switching nodes, L0-L8, L1
1, L12, L21 to L24 ... Link, 11 ... Table management unit, 12 ... In-subnet routing table holding unit, 13 ... Inter-subnet routing table holding unit, 1
4 ... Path setting / release request unit, 15 ... Setting route holding unit,
16 ... MC table creation unit, 17 ... MC routing table registration / deletion unit, 18 ... MC table management unit, 19 ...
MC routing table holder.

Claims (7)

[Claims] 1. A multicast connection method for simultaneously connecting / releasing an originating terminal and a plurality of destination terminals via a network consisting of a plurality of switching nodes in response to a multicast connection / release request from the originating terminal, the network comprising: Is a sub-network of the first layer consisting of a plurality of switching nodes mutually connected by a predetermined link and a plurality of m-1th layers (m is a positive integer of 2 or more) mutually connected by a predetermined link And the m-th layer consisting of the sub-networks, and the m-th layer, in response to a multicast connection request from the switching node accommodating the source terminal or the (m + 1) -th layer, each of the m-th layer sub-networks. Based on a predetermined multicast connection route that establishes a multicast connection between the A bandwidth reservation request is sent to the inter-link in parallel, and a multicast connection within each m-th layer sub-network is requested for each m-th layer sub-network that constitutes the connection route for which the band reservation has been successful In parallel, the m-th layer sub-network responds to the multicast connection request from the m-th layer with respect to the (m-1) -th layer in the m-th layer sub-network. The layer 1 sends a multicast connection request, and the layer 1 has a predetermined multicast connection route for multicast connection between each layer 1 subnetwork in response to the request from the switching node accommodating the source terminal or the layer 2 Bandwidth reservation for each layer 1 inter-subnetwork link that composes this multicast connection route based on In parallel, requesting a multicast connection within each layer 1 subnetwork for each layer 1 subnetwork constituting the connection route for which the bandwidth reservation has been successful, in parallel In the first layer sub-network, in response to a multicast connection request from the first layer, based on a predetermined multicast connection route for establishing a multicast connection between the respective exchange nodes, the link between the exchange nodes constituting this multicast connection route is established. A multicast connection method characterized in that bandwidth reservation requests are sent in parallel to each switching node, and each switching node makes a bandwidth reservation according to the desired communication capacity in response to the bandwidth reservation request for the accommodated link. . 2. The multicast connection method according to claim 1, wherein, as each of the multicast connection routes, the number of sub-networks or the number of switching nodes passing through is the smallest among the multicast connection routes having the same originating and terminating ends. A multicast connection method characterized in that a multicast connection route is used. 3. The multicast connection method according to claim 1, wherein as each of the multicast connection routes, the number of sub-networks or the number of switching nodes passing through is the smallest among the multicast connection routes having the same originating end point and destination end point. A multicast connection route, and
A multicast connection method characterized in that a multicast connection route having the largest reservable bandwidth amount of each link constituting the multicast connection route is used. 4. The multicast connection method according to claim 1, wherein, when a bandwidth reservation request fails in a predetermined connection route among the multicast connection routes, a destination end point on the connection route where the bandwidth reservation fails A multicast connection method, characterized in that a predetermined one-to-one connection request is sent to and from the originating end point of the multicast connection route. 5. The multicast connection method according to claim 4, wherein a call identifier for identifying a multicast connection request from the calling terminal is stored in all requests derived from the multicast connection request, and the switching node receives the request. Based on the call identifier included in the bandwidth reservation request, it is determined whether or not the bandwidth reservation request is due to the same multicast connection request. If bandwidth reservation is made due to the same multicast connection request, a new bandwidth reservation is made. A multicast connection method characterized in that it is not performed. 6. The multicast connection method according to claim 1, wherein a multicast connection route at the end of the multicast connection is held for each layer, and at the m-th layer, from the switching node accommodating the calling terminal or the (m + 1) -th layer. In response to the multicast release request, the band release request is sent in parallel to each of the m-th layer intersubnetwork links that make up the held multicast connection route, and each m-th layer on the multicast connection route A multicast release request for requesting multicast release in each m-th layer sub-network is sent in parallel to the sub-network, and the m-th layer sub-network responds to the multicast release request from the m-th layer by For the m-1th layer in the mth layer sub-network, A multicast release request is sent, and at the first layer, between the first layer sub-networks forming the retained multicast connection route in response to the multicast release request from the switching node accommodating the calling terminal or the second layer. A bandwidth release request is sent to the link in parallel, and a multicast release request is requested in parallel to request each layer 1 subnetwork on the multicast connection route to release the multicast within each layer 1 subnetwork. In the first layer sub-network, in response to the multicast release request from the first layer, the bandwidth release request is sent in parallel to the inter-exchange node links that make up the held multicast connection route, Each switching node releases the desired bandwidth according to the bandwidth release request for the accommodated link. A multicast connection method characterized by the above. 7. The multicast connection method according to claim 1, wherein in a layer one level lower than a layer accommodating the source terminal and all destination terminals in the same sub-network, a predetermined routing registration request from the source terminal is received. , Of the multicast connection routes that have the originating terminal as the originating end point and all destination terminals as the destination end point, configure each multicast connection route with the smallest number of sub-networks or switching nodes to go through. Sequentially rearranging the links in descending order of reservable bandwidth, select the multicast connection route with the largest reservable bandwidth in response to the multicast connection request from the calling terminal, and perform the multicast connection processing. In response to a predetermined routing deletion request from the calling terminal, A multicast connection method characterized in that the rearrangement processing of multicast connection routes is stopped.