JP2006238484A - Repeating apparatus and repeating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that requests of simple transmission, transmission through an explicit path (route) and band guaranteeing transmission in multicast data transmission are increased in the demands of transmission using multicast protocols in accordance with the increase of video transmission in recent years. <P>SOLUTION: In the present invention, when forming a transmission route using a multicast protocol, the address of a repeating apparatus on the transmission route is made explicit in a participation message (explicit path item) or in the policy table of each of repeaters and repeaters within the transmission route are made explicit, thereby forming the transmission route. Furthermore, requested bands (QoS items) are secured in the policy table and entered in the participation message, thereby forming the transmission route where transmission quality is ensured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a network relay device used for forming a multicast transmission route for transmitting and receiving multicast packets (data) between a transmission terminal and a reception terminal by a multicast protocol, and in particular, transmission in a multicast transmission route. It can be used on the terminal side, the receiving terminal side or any of those relay positions, and can facilitate multicast data transmission by ensuring that multicast transmission routes can be recognized by labels, ensuring transmission quality, or explicit transmission The present invention relates to a relay device capable of forming a route.

  Multicast is a form of passing packets (data) to a plurality of recipients on an IP (INTERNET PROTOCOL) network, and only one packet is sent to all recipients on the network. Packets are copied and transferred as necessary at the relay point of the network. It is distinguished from other so-called unicasts that copy and pass data to the recipient, and broadcasts that transfer data throughout the network.

  Generally, a data transmission network is configured in a network using repeaters, and when data transmission from a certain relay device to a target relay device is desired, each relay device intervening until the target relay device is connected. After confirming the address and the like, a transmission route (hereinafter, used as a concept including traffic) is formed and transmitted. It is desired that a transmission route be formed more easily as the network becomes larger and higher speed is required. In addition, from the user (communication service provider), it is desired to form a transmission route that ensures transmission quality QoS (Quality of Service) expressed explicitly as to which relay device is transmitted through operation and represented by a band or the like. It has become.

(Explanation of MPLS)
Conventionally, a method for meeting these expectations is MPLS (Multi Protocol Label Switching), which is mainly used for a relay apparatus that transmits unicast packets.

  Among these, RSVP-TE (Resource Reservation Protocol) is used to form a packet route LSP (Label Switched Path) with a simpler label than a long destination, further form an explicit transmission route, and secure QoS. -Traffic Engineering (Non-Patent Documents 3 and 4) and CR-LDP (Constrained Routed-Label Distribution Protocol) with similar functions.

  Here, RSVP-TE is a protocol for reserving network resources in order to secure QoS, and is also used for explicit LSP establishment. CR-LDP is a protocol that extends the label distribution function (LDP) and enables constraint-based routing and QoS reservation in an MPLS network.

  For example, the transmission route shown in FIG. 10 has been formed using these protocols and a link state routing protocol OSPF (Open Short Path First) that has been widely used for relay apparatuses / links and has topology information. .

  In FIG. 10, the relay device RT2 uses topology information (for example, information instructed from a policy server that manages all networks in advance) as the transmission route to the relay device RT4, in the order of the transmission routes of the relay devices RT3, RT7, RT9, RT4. And the bandwidth (one of the parameters for guaranteeing QoS) in the transmission route is 40 Mbps, and the transmission terminal 200 is now connected from the reception terminal 100 via the relay device RT2. When the relay device RT4 has received a reception request as an intention to receive data from the transmission device 200, the relay device RT2 explicitly indicates the relay device RT3 according to its own topology information. A request including information on the order of the transmission routes is given to the 40 Mbps resource with priority To reserve.

  Similarly, when a request is made in order to the relay devices RT7, RT9, RT4 and a resource of 40 Mbps is secured, labels 100, 110, 120, 130 are sequentially attached and returned from the relay device RT4 to RT2. come. Thereafter, the relay device RT4 transfers the packet with the label 100 to the reserved relay device RT9 at a reserved 40 Mbps. Then, the relay device RT9 replaces the label 100 of the packet with the label 110 and transfers it to the relay device RT7. In this way, the labels 100, 110, 120, and 130 are replaced in this order, and the packet is transferred while securing the bandwidth.

  However, these currently operated MPLSs are mainly used only for relaying unicast packets.

(Description of PIM-SM)
On the other hand, the demand for transmission of video data and the like has increased, and the demand for multicast communication has increased. Multicast communication includes a PIM (Protocol Independent Multicast) protocol (Non-patent Documents 1 and 2).

  In the PIM protocol, a network is formed and data is transmitted under the following conditions.

  (1) The receiver transmits an IGMP Membership Report from the receiving terminal to the relay device of the network to which the receiver belongs. This IGMP Membership Report is, so to speak, a participation message for joining a multicast group, and is an intention display means that desires to receive the multicast data. A multicast group is a specific group of data identified by a multicast address in the network. The transmitting terminal transfers data with a multicast address (the multicast address is also data identification information), and if the receiving terminal wants to receive the multicast data, it wants to join the multicast group There is a need.

  (2) When the relay device that has received the IGMP Membership Report recognizes a terminal that transmits multicast data to a participating group, the relay device recognizes the terminal, and if not, the RP (Rendezvous Point or Shared Point), the intermediate relay device is hop-by-hop (calling the neighboring relay device to join. The order in which the called relay device calls the next neighboring relay device to join). Tell your participation. The route that conveys participation in the transmitting terminal is called Shortest Path Tree (hereinafter referred to as “SPT”), or the route that conveys participation in the RP is referred to as Rendezvous Point Tree (hereinafter referred to as “RPT”). A transmission route is established.

  (3) Multicast data is transferred to the receiving terminal or RP through the constructed multicast transmission route (hereinafter referred to as “transmission route”).

  The details of the above (2) will be described in detail below with reference to FIG. First, SPT will be described. The SPT forms the transmission route from the receiving terminal 100 to the transmitting terminal 200 in the shortest time (it is possible to form a low-cost route), and is performed as follows.

  a. The relay device RT2 that has received the IGMP Membership Report from the receiving terminal 100 checks the unicast routing table, finds a nearby relay device RT3 necessary to form the shortest transmission route, and participates in the formation of the transmission route A PIM Join message that is a participation message is transmitted. Here, the unicast routing table of the relay device RT2 (generally all the relay devices have) includes address information for specifying all networks connected in association with the actual network as well as neighboring networks, multicast addresses, and It stores the address of the relay device connecting these networks and information related to input / output ports (interfaces).

  In the PIM Join message, in order to find the transmission route for obtaining the data requested by itself from the unicast routing table, for example, the address of the multicast group, the address of the transmission source (transmission terminal), and heading there Therefore, the address of the relay device to be next hopped, the cost of the relay device network, and the like are described.

  b. Similarly, a relay device RT3, RT4 (to form the shortest, RT7 and RT9 do not pass in this case) is sent a hop-by-hop PIM Join message, and each relay device holds each time. The transmission route is established while checking the unicast routing table. When the relay device RT4 checks the unicast routing table, the relay device RT4 knows that the transmitting terminal 200 that is transmitting data requested by the received participation message is connected to itself.

  c. After receiving the PIM Join message, the relay device RT4 belonging to the same network as the transmission terminal 200 passes through the transmission route (relay devices RT4, RT3, RT2) in which the multicast data transferred from the transmission terminal is established. Forward to.

  Next, RPT will be described. In the case of RPT, RP (Rendezvous Point or Shared Point) is determined in advance. For example, the relay device RT8 is defined as RP in FIG. 10, and this is transmitted to the relay device of each network. The relay device RT4 that has received the multicast data from the transmitting terminal 200 does not know the terminal that receives the data, and therefore encapsulates the multicast data into the unicast of the relay device RT8 and transfers it to the relay device RT8 that is the RP. After that, the relay device RT2 receiving the IGMP Membership Report from the receiving terminal 100 throws a PIM Join message toward the relay device RT8 in the same manner as the above conditions a and b, and transmits a transmission route (relay devices RT2, RT3, RT7). , RT8). When the relay device RT8 receives the PIM Join message, the relay device RT4 is notified that there are participating members, and a transmission route RPT from the relay device RT4 to RT2 is constructed. Since the relay device RT2 can recognize the transmission terminal 200 when it receives data from the transmission terminal 200 via the relay device RT8 (RP), it issues a request for the relay device RT8 to leave at this point and relays Reconstruct the SPT to device RT4.

  When multicast communication is performed by PIM-SM, it is formed by selecting the shortest transmission route or the transmission route having the lowest cost (statically set attribute for each transmission route). Or traffic is concentrated. In addition, there is a problem that it is difficult for the user to detect which transmission route is being passed, and there are problems that the destination search becomes difficult because the unicast routing table becomes enormous.

(Proposal of multicast in MPLS)
On the other hand, a method for newly realizing multicast communication using MPLS has been proposed (Non-Patent Document 5). This is a method of using RSVP for MPLS label distribution.

  As shown in FIG. 11, in this method, an RSVP Path message (information similar to a participation message) is transmitted from a transmission node S (a node is similar to a relay device) to a reception node L via a relay node. Reach along the route. The receiving node that has received the Path message returns a Resv message. This Resv message is returned by transmitting the MPLS label to the relay node, so that the LSP can be performed.

  However, in this method, all relay nodes need to support RSVP, and there remains a problem in the spread.

Dave Kosiur, translated by Yukio Hamada, Mastering TCP / IP IP Multicast Edition, 1st Edition, Ohm Co., Ltd., November 30, 1999, p. 119-p. 123 D. Estrin, Nine others, “Request for Comment 2362: Protocol Independent Multicast-Sparse Mode (PIM-SM)”, [online], June 1998, Internet Technical Standardization Task Force (Technical Review Organization for Internet Standardization), [2002 Search on August 29, 2009], Internet [link; http: // WWW. ietf. org / rfc / rfc2362. text], p. 1-p. 5 R. Braden, Ed. , Four others, “Request for Comment 2205: Resource Reservation Protocol (RSVP)”, September 1997, Internet Technology Standardization Task Force (Technical Review Organization for Internet Standards Development), [Search August 29, 2002], Internet [ Link; http: // WWW. ietf. org / rfc / rfc2205. text], p. 3-p. 6 D. Outlook, 5 others, “Request for Comment 3209, RSVP-TE: Extensions to RSVP for LSP Tunnels”, December 2001, Internet Technical Standardization Task Force (technical review organization for Internet standard development), August 29, 2002 Search], Internet [link; http: // WWW. ietf. org / rfc / rfc3209. text], p. 3-P. 8 Seisho Yaskawa, 3 others, “Extended RSVP-TE for Multicast LSP Tunnels”, June 2002, Internet Technology Standardization Task Force (Technical Review Organization for Internet Standards Development), [Search August 29, 2002], Internet [http // WWW. ietf. org / internet-draft / draft-yasukawa-mpls-rsvp-multicast-00. text]

  There are situations of each method as described above. On the other hand, video transmission and the like are often requested, and the demand for multicast is increasing. However, the larger the entire unicast routing table, the larger the amount of information in the table and the greater the check time.If there are more intermediary relay devices, the participation message is added to the table check time. The number of transmissions increases and takes time. In addition, it is important to ensure the quality of the bandwidth and the like.

  In view of the above situation, an object of the present invention is to provide a relay apparatus and a relay method that can explicitly form a transmission route by a multicast protocol, and can guarantee a quality by securing a band when these transmission routes are formed. is there.

  In order to achieve the above object, claims 1 to 5 are configured so that an explicit transmission route can be formed. Specifically, in the first aspect of the present invention, a transmitting device including a transmitting terminal or a higher-order other relay device capable of transmitting data from the transmitting terminal, and a receiving terminal or a lower-level to which the receiving terminal is connected In order to form a transmission route using a multicast protocol with a receiving device including other relay devices, the relay device is used closest to the receiving device and desires to receive the data from the transmitting device Policy storage means for receiving and storing transmission route information for identifying other relay devices on the transmission route between the receiving device and the receiving device, and for receiving the data from the transmitting device When a participation message is received from the receiving device and the transmission route information has only one specific information about another relay device in the upper neighbor, only the participation message is transmitted. When the transmission route information includes specific information about a plurality of other upper relay devices, at least the transmission route information includes the transmission route information from other relay devices in the upper neighbor to the transmission device A transmission route formation management means for generating and sending a message, and the other relay device in the neighborhood to which the transmission route formation management means has sent the participation message is used as the data transfer source, and the reception device that has received the participation message is transferred. And transfer information storage means for storing as a destination.

  In the invention of claim 2, a transmitting device including a transmitting terminal or another upper relay device capable of transmitting data from the transmitting terminal, and another lower relay device to which the receiving terminal or the receiving terminal is connected In a relay device used as a relay device that forms a transmission route by transmitting / receiving a join message using a multicast protocol to / from a receiving device including a receiver, the join message is received from another relay device in the lower neighborhood In addition, when it includes transmission route information for specifying another relay device up to the transmission device in order to receive the desired data from the transmission device, the higher order selected according to the received transmission route information Transmission to other transmitters in the neighborhood from at least one other relay device in the upper neighbor of the transmission route information received to the transmitter. A transmission route formation management unit that generates and transmits a participation message including route information, and another relay device in the upper neighbor that has transmitted the participation message by the transmission route formation management unit as a transfer source of the data, and participates Transfer information storage means for storing another relay device in the lower neighborhood that has received the message as a transfer destination.

  According to a third aspect of the present invention, there is provided policy storage means for receiving other high-order neighboring relay devices to which a self message should be transmitted in response to an instruction from the outside, and the transmission route formation management means includes When transmission route information is not received from another neighboring relay device, the participation message is transmitted to another higher neighboring relay device stored in the policy storage means.

  In the invention of claim 4, a transmitting device including a transmitting terminal or another higher-order relay device capable of transmitting data from the transmitting terminal, and a lower-order other relay device to which the receiving terminal or the receiving terminal is connected In the relay method of forming a transmission route by a multicast protocol with n relay devices with a receiving device including the data, the transmitting device and the data from the transmitting device are transferred to the n = 1st relay device nearest to the receiving device. A preparation step of receiving transmission route information specifying the n relay devices on the transmission route with the desired receiving device from the outside and storing them in the policy storage means, and n = 1st nearest to the receiving terminal The relay device receives a participation message including the transmission route information for receiving the data from the transmission device from the reception device, and transmits the participation message according to the transmission route information. To the n = 2nd relay device selected in step S3, a participation message including transmission route information for identifying at least the remaining n-2 relay devices is generated and transmitted, and the receiving terminal transmits the data transfer destination. And storing the first relay device as a transfer source in its own transfer information storage means, and the k (2 to n−1) th relay device is at least n−k from the k−1th relay device. In response to the participation message including the transmission route information specifying the number of relay devices, the transmission route information specifying the remaining n−k−1 relay devices is sent to the (k + 1) th relay device selected by the transmission route information. Including and transmitting a participation message including the k-1th relay device as the data transfer destination, the k + 1th relay device as the transfer source, and storing them in its own transfer information storage means. The operation is sequentially performed by the k = 2 to k = n−1 relay device, the nth relay device receives the participation message from the n−1 relay device, and the n−1 relay device. And the transmission device as a transfer source and storing it in its own transfer information storage means, and when each of the first relay devices from n receives the data in turn, the transfer of its own transfer information storage means Transferring the data with reference to the information.

  In the invention of claim 5, a transmission device including a transmission terminal or another higher-level relay device capable of transmitting data from the transmission terminal, and a lower-level other relay device to which the reception terminal or the reception terminal is connected In a relay method for forming a transmission route according to a multicast protocol with n relay devices in order to receive desired data from the transmission device, the transmission for receiving the data A preparatory stage for receiving information identifying the upper neighboring relay device from the outside and storing it in the policy storage means for each relay device from n = 1 to n−1 for forming a route, and n = 1st relay The relay devices from the device to the (n-1) th relay device receive the participation message from the lower neighboring receiving device or the relay device in order, and are stored in their own policy storage means. To position points of the relay device sends a join message by n-th relay device receives the participation message from the n-1-th relay device, and a step of forming the transmission routes.

  Furthermore, in the inventions according to claims 6 to 7, the LSP transmission route, the explicit transmission route, and the transmission route for which quality is ensured can be used. Specifically, in the invention of claim 6, a transmitting apparatus including a transmitting terminal or other upper relay apparatus capable of transmitting data from the transmitting terminal and a receiving terminal or the receiving terminal connected to the receiving terminal or the receiving terminal. A relay device used to form a transmission route by a multicast protocol with a receiving device including another relay device, between the transmitting device and the receiving device that desires the data from the transmitting device In order to store information for satisfying a request for forming a specific transmission route specified from the outside or a request for ensuring transmission quality of a specific quality parameter when forming the transmission route Policy storage means and routing information for identifying neighboring and associated networks and other relay devices connecting them An association network information storage means, and a participation message including identification information for specifying and receiving the data from the transmission device is received from the reception device or another relay device in the lower vicinity, and the identification information is received. Based on the information stored in the policy storage unit and the routing information stored in the association network information storage unit, and when the other neighboring relay device is selected with priority given to the information stored in the policy storage unit, the selection is performed. When the information is requested to another relay device higher than the other relay device in the upper neighbor when the policy storage means is referred to the other relay device in the upper neighbor A transmission route forming pipe for generating a participation message including information required for the other upper relay apparatus and the identification information and transmitting it to the other upper relay apparatus. And the other relay device in the upper neighbor that has transmitted the participation message by the transmission route formation management means, and transfers the receiving device or the other relay device in the lower neighbor that has received the participation message. And transfer information storage means for storing as a destination.

  In the invention of claim 7, the transmission route formation management means refers to the information in the policy storage means and the routing information in the association network information storage means, and transmits the data specified by the identification information. When it is determined that it is connected to itself, the transmission device is set as a transmission source, and the transfer information storage means stores other lower-layer neighboring relay devices that have received the participation message as transfer destinations.

  As described above, in the present invention, in multicast data transmission, LSP can be formed, so that easy transmission can be performed, and because the configuration is such that QoS operation is performed, it is possible to secure bandwidth and perform high-quality transmission. Since the transmission route can be formed, the user can grasp the transmission route.

  In addition, the structure and effect in these combinations can also be achieved.

  FIG. 1 is a diagram showing an embodiment of the present invention, and shows a functional configuration of a relay device for multicast data transmission. The same reference numerals used in the description of the embodiment of the present invention as those described in the prior art indicate the same functions.

(Description of configuration of relay device MCRT)
The configuration of the relay device according to the present invention will be described with reference to FIG. 1 basically constitutes a basic configuration that achieves most of the functions according to the present invention. Depending on the claimed invention, or whether the relay device is used closest to the receiving terminal. Functional parts that are not essential depending on whether they are used between relay devices are also included. However, the product can usually include all means.

  In the transmission route formation management means 1, the message reception processing unit 1a receives an IGMP Membership Report (or IGMP Join) from the receiving terminal 100 (see FIG. 3 explaining the transmission route) and a PIM Join message from a neighboring relay device. The participation message is received, and the participation message is notified to the routing processing unit 1b, the label allocation processing unit 1c, and the reservation reception processing unit 1d. The format of the participation message is shown in FIG. This format is applicable to the invention described in any claim. Of the information included in the participation message here, information common to the embodiments (1 to 4 in FIG. 2) is the same as that described in the prior art. In particular, the label term, QoS term, and explicit path term in FIG. 2 are information according to the present invention. The message reception processing unit 1a has a function of transmitting and receiving a participation message. In the description of each part below, for example, the expressions “send a participation message” and “receive a participation message” have no problem in the explanation of the invention. The expression which abbreviate | omitting sending / receiving through 1a is taken.

  The routing table 2 is generally called a unicast routing table. The routing table 2 connects not only the neighboring networks but also the address information for identifying all networks to which the relay device MCRT is actually connected in direct or indirect connection, multicast addresses, and those networks. The information of the relay device address and the data input / output port or the input / output port (interface) relationship information of the participation message is stored in a table. The information in the routing table 2 (included in the associative network information storage means in the claims) is used to form, for example, the shortest transmission route SPT or RPT (or a low-cost transmission route).

  The routing processor 1b refers to the participation message received from the receiving device or the lower neighboring relay device and the routing table 2 and searches for the address of the next higher neighboring relay device (hereinafter referred to as a transmission route formed thereby). Is referred to herein as a routing transmission route.) The participation message from the subordinate relay device or the receiving terminal is rewritten to generate a new participation message, and the participation message is sent to the found relay device. A higher-order relay device is located closer to the transmission device than the relay device on the transmission route when attention is paid to any relay device on the transmission route from the transmission device to the reception device via a plurality of relay devices. Similarly, the lower relay device refers to a relay device positioned closer to the receiving device than the relay device on the transmission route.

  When the received participation message has a label (when forming an LSP), the label allocation processing unit 1c generates a new label that can be recognized by itself and replaces the label of the participation message with the newly generated label. . On the other hand, the label allocation unit processing unit 1c generates the label received from the lower relay device as the transfer destination label of the label table 4a (see the format example in FIG. 4) of the transfer information storage unit 4 as the transfer source label. Then, the label transmitted to the upper level becomes the input / output interface (the input / output port when the data is actually transmitted after the transmission route is formed. , Called IF). The label table 4a represents the transfer source relay device and the transfer destination relay device when transferring data with labels. Here, the label means a kind of identification information represented by a value, a sign, or the like.

  In the example of the label table of FIG. 4, only the portions necessary for the description are described, but actually, labels for all IF (ports) of the relay apparatus are provided.

  The policy table 3 (policy storage means) has information as shown in FIG. 6A, and the filter portion includes Dest IP. This Dest IP corresponds to a multicast group address included in IGMP Join which is a participation message from the receiving terminal. Correspondingly, a quality parameter indicated by a bandwidth or the like is shown in the required QoS column.

  The reservation reception processing unit 1d made a request for participation by comparing and referring to the multicast group address of the IGMP Join that was consulted (identification information for specifying the data in the claim) and the Dest IP of the filter part of the policy table 3 It is determined whether or not the transmission route (traffic) is a quality assurance target. In other words, if the multicast group address of the participation message corresponds to the group address described in the policy table of FIG. 6 and a necessary quality parameter is described as “request QoS”, it is determined that it is a target of quality assurance. In this case, the traffic management database 5c is checked to check whether the line capacity transmitted by itself is sufficient or whether traffic can be allocated.

  Here, the line capacity will be simply described in terms of bandwidth. Each network to which each relay device is connected has a finite frequency band (corresponding to the maximum bandwidth of the line capacity in this case). When data having a plurality of predetermined bands is transmitted to the one network, the network band may be exceeded, and the data transmission quality may deteriorate. Therefore, in order to ensure transmission quality, an interface (resource) for transmitting the data is determined and reserved when forming a transmission route for the required data, and the reservation is performed when the transmission is actually performed after the transmission route is formed. It is necessary to preferentially transmit other data through the specified interface.

  The “QoS traffic allocation procedure” is determined and executed as follows. If the traffic output ports (IF) are P1, P2,..., Pn, for example, the maximum traffic capacity to be newly allocated (the maximum bandwidth requested in the policy table) is [the line capacity of the port P1 (of the usable bandwidth). Size) —the sum of the maximum transmission rates (maximum bandwidths) already allocated], the bandwidth of the traffic can be guaranteed. Similarly, all the ports forming the traffic are judged, and if the bandwidth can be guaranteed, the quality parameter and the Q ID (Queue ID: referred to as queue ID or Q ID) are recorded in the traffic management database 5c. That is, the quality (bandwidth) required for the output port is reserved with the Q ID (see FIG. 7).

  The policy table 3 is also used for receiving an instruction for an explicit transmission route from a policy server (not shown) that controls the entire network in advance when an explicit transmission route is formed. In this case, unlike the transmission route formation by the routing described above, the reservation reception processing unit 1d uses the address of the next higher-order neighboring relay device explicitly specified in advance in the policy table 3 (hereinafter referred to as transmission formed thereby). The new participation message is transmitted to a route (referred to as an explicit transmission route). By writing the address of the relay device of the explicit transmission route in the new participation message, it is transmitted to each relay device (shown in items 9 to 13 in FIG. 2). An example of the policy table 3 in which an explicit transmission route is specified is shown in FIG. 6B. The address of each router with k = 1, 2, 3 shown in the router list in FIG. 6B identifies the router that constitutes the explicit transmission route.

  Further, based on the transmission route information formed by the transmission route formation management unit 1 (that is, the routing processing unit 1b, the reservation reception processing unit 1d, or the label allocation processing unit 1c), the transfer information storage unit 4 stores For example, in the general flow table shown in FIG. 5A, the identification information of the transfer source and transfer destination of the multicast data (hereinafter referred to as data) (the transfer source and transfer destination are subordinate from the relay device at the upper level of the transmission route). The address may be indicated by an address (FIG. 5 (b)), or may be indicated by a label (FIG. 4). In addition, the data transmission source and transmission destination identification information (hereinafter, the addresses of the transmission terminal and the reception terminal) are stored.

  When transferring by label, a label table is prepared so that the transfer destination and transfer source labels can be identified as shown in FIG.

  Information necessary for data transfer such as the label table 4a and the flow table 4b of the transfer information storage means 4 may be combined with the routing table 2 to form an integrated table. An example is shown in FIG. The routing table 2 is used when a transmission route is formed, and the information in the transfer information storage unit 4 is information used when data is transmitted after the transmission route is formed, and can be integrated.

  The data transmission management means 5 in FIG. 1 receives data transmitted from the relay device or network of the transmission terminal 200 after the transmission route is formed by the transmission route formation management means 1, and It is transferred (transmitted) to the relay device or network. The packet processing unit 5a of the data transmission management means 5 in FIG. 1 forms a transmission route by classifying data (packets) input via an input interface (including ports), routing by the transmission route formation management means 1, and the like. As necessary, the transmission route information necessary for data transfer such as the label table 4a and the flow table 4b of the transfer information storage means 4 is rewritten. Further, the packet processing unit 5a classifies the received data, determines whether or not it corresponds to the flow table 4b or the label table 4a, and if so, attaches a Q ID (Queue ID) to the traffic. Send to manager 5b.

  The traffic manager 5b includes a buffer 5d, a packet scheduler 5e, and a traffic management database 5c. The traffic manager 5b reserves a buffer 5d for traffic reserved in the traffic management database 5c when, for example, QoS reservation is made in the reservation reception processing unit 1d. When data with a Q ID is input from the packet processing unit 5a there, it is confirmed in advance whether it is reserved or not, and if it is reserved, it is sent via the buffer 5d already reserved. Data is sent, and the packet scheduler 5e guarantees the quality required for QoS from the port shown in the traffic management database 5c, and outputs the data to the transfer destination or destination shown in the flow table 4b or label table 4a.

  Although FIG. 1 is represented by functional blocks, examples of implementation means may include a CPU and memories (ROM and RAM). The functions that the transmission route forming unit 1 and the data transmission management unit 5 manage while managing the routing table 2, the policy table 3, the label table 4a, and the flow table 4b are programmed and stored in advance. It has been achieved by being executed. In achieving the functions of FIG. 1, the configuration may change depending on the number, combination, etc. of the CPU, memory and program used, but none of them is in the scope of the present invention.

(Embodiment 1)
Next, the operation will be described along the flow shown in FIG. 9, taking the schematic network of FIG. 3 as an example. In the first embodiment, an example of (1) formation of an LSP (Label Switched Path) by multicast routing and (2) ensuring transmission quality indicated by a band or the like will be described.

  In the network of FIG. 3, the multicast traffic according to the TCP / IP communication system has a receiving terminal 100 and a relay device (a router as a kind of relay device) before data transmission / reception as described in the section of the prior art. Then, since it is described as a router as an example, it is described as a router.) By exchanging IGMP packets (including IGMP Join) as a participation message, distribution is started and stopped. In a network in which a plurality of routers are present, a transmission route is determined by a routing protocol called PIM-SM. At that time, a PIM join which is a participation message is sent.

(Description of operation of router MCRT3 in receiving terminal in embodiment 1)
The message reception processing unit 1a of the router MCRT3 receives a participation message (IGMP) as shown in FIG. 2 from the receiving terminal 100, and notifies the routing processing unit 1b, the label allocation processing unit 1c, and the reservation reception processing unit 1d (step). S1). The routing processing unit 1b checks whether there is information for identifying the multicast group address, the transmission source (transmission terminal), the reception terminal, etc. included in the participation message in the routing table 2, and if not, newly generates and adds it. If so, shortage information such as an interface (port) number of the router MCRT3 connected to the receiving terminal is added (step S2).

  On the other hand, the received participation message has a column for describing the TYPE of the message. Since this participation message is from the receiving terminal 100, it is confirmed that the TYPE is “IGMP” (step S3).

  Since the reservation reception processing unit 1d notifies the multicast group address (Dest IP) that the user wants to join in the received participation message (IGMP), the reservation reception processing unit 1d searches the filter portion of the policy table 3 (see FIG. 6) (steps S4 and S5). . If it is not found in the table as a result of the search, the bandwidth (quality) is not guaranteed for the traffic, so flow management bound to the best effort queue (Q ID = 0) is performed (step S6). In this case, for example, the buffer of the buffer means 5d is secured for data transmission only when there is a margin in the band, and this is not the case when there is no margin. Thereafter, label assignment is performed (step S17).

  If the traffic requested by the participation message (IGMP) as a result of the search of the policy table 3 requires a QoS operation (reserving / reserving resources necessary for transmitting data in the required bandwidth (quality)), the traffic The management database 5c (see FIG. 7) is examined to check whether the line capacity is still sufficient and traffic can be allocated. Specifically, quality parameters (maximum bandwidth, minimum bandwidth, etc.) required from the policy table 3 are extracted, and determined and implemented according to the above-described “QoS traffic allocation procedure” (steps S7, S8, S9). To do.

  If bandwidth can be guaranteed at all output ports forming traffic, a 20-bit label is assigned (the label value can be any unique value not used elsewhere), and the transfer source (reception) label of the label table 4a Are registered in the traffic management database 5c (here, Q ID 2) as shown in FIG. 7 (steps S10 and S11). Here, for example, the transfer source label is set to 3. OXFFFF is written as the transfer destination (transmission) label of the label table 4a (see FIG. 4A). OXFFFF means that it is connected to the same network as the network to which the receiving terminal 100 belongs, so that it becomes the last router of the LSP to be formed, and the shim header (label) is removed at the end of data transmission. Means to instruct the packet processing unit 5a to transmit to the receiving terminal 100. Further, an interface number to be a transmission / reception port is attached to the label table 4a (see FIG. 4A).

  Up to this point, the reservation of the bandwidth has been reserved in the router MCRT3. When it becomes impossible to allocate a band in step S9, the band is not guaranteed as in step S6 (step S9a).

Next, the policy table 3 is searched, and it is checked whether or not an upper router of the router MCRT3 in FIG. 3 is specified (step S12). If so, an explicit transmission route is formed along step S14. The formation of this explicit transmission route will be described later as another invention. If not specified, the routing processing unit 1b refers to the routing table 2 and the multicast group address of the received participation message in FIG. 2 and searches for the address of the router that will next issue the participation message. For example, when searching for the shortest transmission route, the router MCRT2 is searched. Then, a new participation message (PIM Join) is generated and transmitted to the router MCRT2 (step S13). In the participation message at this time, the self-assigned label = 3 and the quality (QoS) parameters (maximum bandwidth 300 kbps, minimum bandwidth 250 kbps, maximum delay 20 msec) include the format of the participation message (items 6, 7, and 8 in FIG. 2). In the QoS section).

(Description of operation of router MCRT2 in the first embodiment)
Next, the operation of the router MCRT2 will be described based on the flow of FIG. Although the names of the constituent elements in the description are the same as those of the router MCRT3, each element operates as an element of the router MCRT2 shown in FIG. Router MCRT2 receives the participation message (PIM Join) from router MCRT3 (step S1). Since the TYPE of this participation message is PIM Join, the process when the participation message is PIM is performed (step S3-No). First, it is determined whether or not the transmitting terminal is connected to the network to which the transmitting terminal is connected (step S20). When the transmitting terminal 200 is not connected to the network to which the transmitting terminal 200 is connected (step S20—No), that is, since its own upper router MCRT1 exists, the label is assigned (step S21).

  Next, after seeing that there is a QoS request in the participation message, it is started to examine whether or not the requested quality parameters (bandwidth, etc.) can be secured (step 22)). In other words, the traffic management database 5c is examined to check whether the line capacity (available bandwidth) is still sufficient and traffic that can secure the quality parameters required in the QoS term of the participation message from the router MCRT3 can be allocated. To do.

  Specifically, it is performed in the same manner as the above “QoS traffic allocation procedure” (same as steps S7, S8, S9) (step S22).

  If bandwidth can be guaranteed at all the output ports forming the traffic, a label is allocated, and the allocated label is registered as a transfer source (reception) label of the label table 4a (see FIG. 4B), and at the same time, the traffic management database 5c (here Register to QID 5) (step S23). Here, for example, the transfer source label is 9. As the transfer destination (transmission) label of the label table 4a, the label 3 in the participation message received from the lower router MCRT3 is written. When allocation becomes impossible in step S22, the bandwidth is not guaranteed and registered in the label table 4a (step S24).

  Since these are intermediate routers of LSP (Label Switched Path), when receiving a packet (data) with a label 9 attached to the shim header, the packet is rewritten to 3 and transmitted to the router MCRT3. This means instructing the processing unit 5a. Further, an interface number to be a transmission / reception port is attached to the label table 4a (see FIG. 4B) (step S23). Here, although the label table 4a can be integrated with the routing table 2, only a portion related to the router MCRT2 is extracted and shown in FIG. One item of FIG. 8 includes the information of FIG. 4B.

  In FIG. 8, items 1 and 2 have the same source address and different group addresses (multicast) because, for example, two types of information, G1 address information and G2 address information, are transmitted from the same transmitter. In addition, the transmission route formed in this embodiment indicates that it wants to receive information on the G1 address.

  In addition, since the upper router is not specified in the policy table 3 (step S26), the routing processing unit 1b refers to the routing table 2 and the received participation message to search for a router that issues the next participation message. For example, the router MCRT1 is searched for. Then, a new participation message (PIM Join) is generated and transmitted to the router MCRT1 (step S27). The participation message at this time includes a label = 9 assigned by itself and a quality (QoS) parameter (maximum bandwidth 300 kbps, minimum bandwidth 200 kbps, maximum delay 20 msec) in the format of the participation message (items 6, 7, and 8 in FIG. 2). In the QoS section).

(Description of operation of router MCRT1 in Embodiment 1)
Next, the operation of the router MCRT1 will be described based on the flow of FIG. Although the names of the constituent elements in the description are the same as those of the routers MCRT2 and 3, each element operates as an element of the router MCRT1 that is also shown in FIG. The router MCRT1 receives the participation message from the router MCRT2, but since it is PIM Join, the router MCRT1 performs a process when the participation message is PIM (step S3-No). First, it is determined whether or not the transmitting terminal is connected to the network to which the transmitting terminal is connected (step S20). If it is found from the routing table and the participation message that the transmission terminal 200 is connected to itself (step S20—Yes), the QoS request bandwidth is determined by looking at the presence of the QoS request in the participation message. An operation for examining whether it is possible to secure is started (step S31).

  That is, the traffic management database 5c is examined, and it is determined whether or not it is possible to allocate traffic that can secure the quality parameter required in the QoS term of the participation message from the router MCRT2 because there is still a margin in the line capacity (available bandwidth). To check.

  Specifically, it is performed in the same manner as the “QoS traffic assignment procedure” (same as steps S7, S8, and S9).

  In the flow table 4b (see FIG. 5B), the transmission destination address (192.168.30.253) and the transmission source address (192.168.50.253) included in the participation message from the router MCRT2 are respectively shown. Register the destination address and source address on the table. Similarly, label 9 in the participation message from router MCRT2 is written in the transfer destination (output) label. Since this is the LSP (Label Switched Path) top-level router (router to which the transmission terminal 200 is connected), a packet transmitted from the transmission source (transmission terminal 200) to the transmission destination writes a shim header (label 9). In addition, it means that the packet processing unit 5a is instructed to transmit toward the router MCRT2. Further, the output interface number 2 is written in the output IF (step S32) (see FIG. 5B).

(Data transmission in the first embodiment)
As described above, the LSP from the transmission terminal 200 to the reception terminal 100 is established, and the LSP with reserved bandwidth is formed. Next, the router MCRT1 refers to the flow table of FIG. 5B, attaches the label 9 to the data, and transfers the data from the reserved bandwidth interface 2 (port) to the router MCRT2. The router MCRT2 receives the data attached with the label 9 from the interface 2 of the router MCRT1, attaches the label 3 with reference to the label table of FIG. 4B, and starts from the bandwidth reserved interface 3 (port). Transfer to router MCRT3. Similarly, the router MCRT3 refers to the label table shown in FIG. 4A and removes the label and transfers it to the receiving terminal.

  These transfers are performed by the data transmission management means 5 of each router. Specifically, when the packet processing unit 5a refers to the label table 4a or the flow table 4b and adds a Q ID and sends it to the traffic manager 5b, the traffic manager 5b is previously reserved in the traffic management database 5c. Bandwidth is guaranteed according to the ID and transmitted.

  The above-mentioned data transfer is characterized in that the label attached to the data is replaced and transferred.

(Embodiment 2)
In the second embodiment, (3) a transmission route managed by an address by multicast routing is formed (not managed by a label like the LSP transmission route of the first embodiment), but indicated by a band or the like. An example of a relay apparatus capable of ensuring transmission quality will be described focusing on differences from the first embodiment, assuming that the relay apparatus operates along the flow shown in FIG. 9 on the schematic network of FIG.

  In the router MCRT of this example, the label allocation processing unit 1c and the label table 4a in FIG. 1 do not operate, the flow table 4b is used, and the label is not used in FIG. The operation of the other configuration is the same as that of the first embodiment.

  Moreover, in the flow in FIG. 9, there is no label allocation in step S10 and step S21. Instead, in steps S13 and S27, a flow table in which the address of the upper neighbor router MCRT found by routing is the transfer source address and the address of the lower neighbor router MCRT that has transmitted the join message first is the transfer destination. Each router generates 4b (see FIG. 5A). Eventually, after the transmission route is formed by the routing, the data transmission management means 5 of each router MCRT refers to the address of the flow table 4b and transfers the data to the receiving terminal 100. That is, the transfer destination and the transfer source address are switched and transferred.

  As described above, even if the multicast transmission route is managed by the address, the quality can be guaranteed by the QoS operation.

(Embodiment 3)
In the third embodiment, (4) an LSP is explicitly formed by multicast, and (2) an example of ensuring transmission quality indicated by a band or the like is also described. In the description of the third embodiment, the difference from the first and second embodiments will be mainly described on the assumption that the operation is performed along the flow shown in FIG. 9 on the schematic network of FIG.

  There are two possible methods for forming an explicit LSP. One is that when the nearest router MCRT3 to the receiving terminal 100 has identification information of all the routers up to the transmission unit 200 in its own policy table 3, the other one is that each router has its own policy table. The upper neighbor router to be hopped to 3 is specified, and there are two cases. In either case, each policy table 3 is stored in accordance with an instruction from a policy server (not shown) that controls the network. The instruction is issued in the form of answering the inquiry to the policy server after receiving the participation message from the lower receiving terminal 100 or the router MCRT. The policy server is set when the user desires transmission through an explicit transmission route.

(Embodiment 3: When router MCRT3 has all information of explicit transmission route)
In this case, for example, when the user wants to transmit data to the policy table 3 of the router MCRT3 via the router MCRT4, according to the request, the router lists the policy table 3 in order from the top in the transmission route of FIG. The addresses of the routers MCRT4, MCRT2 and MCRT1 are stored. Even when a QoS operation is requested, information such as quality parameter information is stored as in the first embodiment. An example of the policy table 3 is shown in FIG. In FIG. 6B, a router list is added in addition to the policy table items of FIG. For example, when the router list shown in FIG. 6B is applied to the transmission route shown in FIG. 3, this router list is held by the router MCRT3. Addresses of routers MCRT4, MCRT2, and MCRT1 are shown.

  The router MCRT3 is different from the first embodiment in that the operation of step S14 or step S28 is performed in the flow of FIG. In this example, transmission route formation by routing in step S13 and step S27 in FIG. 9 is not performed.

  Specifically, the router MCRT3 checks the router list in the policy table 3 and searches for an upper router to which a participation message should be issued (step S12). The first router MCRT4 in the searched router list is determined as a neighboring router that issues a join message. The join message includes a label attached by itself and addresses of the remaining routers in the router list (in the above example, routers MCRT2, MCRT1). Of the address) is sent to the router MCRT4 (step S14). Note that the entire router list of the router MCRT3 may be sent, but, for example, the router MCRT1 is unnecessary because there is no destination for the participation message.

  The router MCRT4 and the router MCRT2 follow the steps S26 and S28 in FIG. 9 to the upper router designated by the participation message received from the lower router, that is, in this example, the router MCRT4 sends the router MCRT2 to the router MCRT2. The participation message including the address of MCRT1 is sent, and the router MCRT2 receiving it sends the participation message to the router MCRT1 (step S28). Also, the label attached by each router is included in the participation message as in the first embodiment.

  Data is transferred while referring to the flow table and the label table in the order of the routers MCRT1, MCRT2, MCRT4, and MCRT3 formed in this way.

  Other operations such as label table creation and bandwidth reservation are performed in the same manner as in the first embodiment.

(Embodiment 3: When each router holds information on a router to be hopped)
In this case, for example, when the user desires to transmit data via the router MCRT4 during the transmission route of FIG. 3, according to the request, the policy table 3 of each router on the transmission route of FIG. As the router list, the router MCRT3 stores the address of the router MCRT4, the router MCRT4 stores the address of the router MCRT2, and the router MCRT2 stores the address of the router MCRT1. That is, each router knows the address of the router MCRT that it should hop next. When a QoS operation is requested, in this example, a quality parameter such as a required bandwidth is stored only in the policy table 3 of the router MCRT 3 as in the first embodiment, and the operation is the same as in the first embodiment. is there.

  Hereinafter, based on the flow of FIG. 9, it demonstrates centering on the difference with said each embodiment. The router MCRT3 checks the router list of its own policy table 3 and searches for an upper router to which a participation message should be issued (step S12). Since the upper router to be searched for is the router MCRT4 in this example, a join message is sent together with the label attached thereto.

  Similarly, in accordance with steps S26 and S28 of FIG. 9, router MCRT4 sends an address message to router MCRT2 in its own router list, and router MCRT2 sends a join message to router MCRT1 in its own router list.

  Data is transferred while referring to the flow table and the label table in the order of the transmission routes thus formed, that is, the routers MCRT1, MCRT2, MCRT4, and MCRT3.

(Embodiment 4)
In the fourth embodiment, the explicit LSP formation and the QoS operation have been performed in the third embodiment. (5) Although an explicit transmission route is formed, the address (of the third embodiment is used). This is an example of a transmission route to be managed (instead of such a label) in which no QoS operation is performed. In other words, the fourth embodiment is such that an explicit transmission route is formed in the second embodiment.

  Differences from the third embodiment will be described with reference to FIG. In FIG. 9, steps S10 and S21 for performing the label allocation work and steps S7, S8, S9, S11, S20, and S23 for performing the QoS operation are not performed. Further, an explicit transmission route is formed by referring to the router list of the policy table 3 as in the third embodiment. The transfer source and transfer destination addresses necessary for data transfer at that time are registered in the flow table 4b. Manage. This is achieved by creating the flow table 4b when issuing a participation message in step S14 and step S28.

(Embodiment 5)
The fifth embodiment is the invention of claims 15, 16 and 17, and is a superordinate concept invention in the above embodiment. That is, the invention of each of the above embodiments can be operated alone or in combination, that is, an operation represented by one flow as shown in FIG. Details of the implementation have been described above and are omitted here.

  Next, although common to each embodiment described so far, a mode of use of the present invention will be described. A relay device used for the entire related network (hereinafter, the relay device according to the present invention will be mainly described, but the same applies to the relay method according to the present invention) is configured by the relay device according to the present invention. Of course, it can be used for a part of the whole related network. For example, in a simple configuration, the relay device according to the present invention is adopted from the receiving terminal to k relay devices, and the (k + 1) th to nth relay devices on the transmission route are conventional type relay devices. There is also a method of use in which the transmitting terminal is connected to the nth (n> k) conventional type relay device. In this example, “k + 1 to n-th relay devices and transmission terminals connected thereto” are described in “Claim other relay devices capable of transmitting multicast data from the transmission terminal” This corresponds to a “transmitting device including”.

  On the other hand, up to the kth relay device can be configured as a conventional type, and the (k + 1) th and subsequent relay devices can be configured as the relay device of the present invention. In this case, “the relay device from the receiving terminal to the kth relay device” corresponds to “a receiving device including other lower relay devices to which the receiving terminal is connected” described in the claims.

  Also, the relay device from the receiving terminal to the kth and the relay device from the k + mth (n> k + m) to the nth connected to the transmitting terminal are configured by conventional type relay devices, from k + 1 to k + m−1. The relay device according to the present invention can also be used as the relay device. These have been described with a simple transmission route, but in reality, a number of networks are connected to one relay device, and many of the relay devices and networks are connected and used. Even in such a case, the relay device and the relay method according to the present invention can be used.

  In the embodiments described so far, the SPT transmission route has been configured based on the network shown in FIG. 3, but the RP (Rendezvous Point or Shared Point) described in the section of the prior art is used. The present invention can also be applied when configuring an RPT transmission route.

  In addition, the multicast protocol is not limited to the example here, and there are many that include the PIM protocol and the like. Of course, these are included in the present invention. Those with equal thoughts are included.

The figure which shows the example of a function structure of the relay apparatus (router) of this invention The figure which shows the format example of the participation message required for the transmission route formation of the multicast data transmission based on this invention The figure for demonstrating the transmission route formed by the relay apparatus (router) of this invention The figure which shows the label flow which concerns on this invention The figure which shows the flow table which concerns on this invention The figure which shows the policy table which concerns on this invention The figure which shows the traffic management database which concerns on this invention The figure which shows the example which combined the routing table and label table in this invention The figure which shows the relay apparatus (router) operation | movement flow in this invention Diagram for explaining the prior art Diagram for explaining the prior art

Explanation of symbols

  1: transmission route formation management means, 1a: message reception processing section, 1b: routing processing section, 1c: label allocation processing section, 1d: reservation reception processing section, 2: routing table (association network information storage means), 3: policy Table (policy storage unit), 4: Transfer information storage unit, 4a: Label table, 4b: Flow table, 5: Data transmission management unit, 5a: Packet processing unit, 5b: Traffic manager, 5c: Traffic management database, 5d: Buffer means, 5e: packet scheduler, 100: receiving terminal, 200: transmitting terminal, MCRT1 to MCRT5: relay device (router), RT1 to RT9: relay device, N: relay node, S: transmitting node, L: receiving node

Claims (7)

Between a transmitting apparatus including a transmitting terminal or another upper relay apparatus capable of transmitting data from the transmitting terminal and a receiving apparatus including a receiving terminal or another lower relay apparatus to which the receiving terminal is connected In order to form a transmission route according to the multicast protocol, a relay device used closest to the receiving device,
Policy storage means (3) for receiving and storing transmission route information for specifying another relay device on the transmission route with the receiving device that wishes to receive the data from the transmitting device from the outside When,
When a participation message for receiving the data from the transmission device is received from the reception device, and the transmission route information has only one specific information about another relay device in the upper neighbor, only the participation message is received. And when there is specific information about a plurality of other upper relay devices in the transmission route information, at least transmission route information from other relay devices in the upper neighbor to the transmission device in the transmission route information A transmission route formation management means (1) for generating and sending a participation message including:
Transfer information storage means (4) for storing, as the data transfer source, another neighboring relay device to which the transmission route formation management means has transmitted the participation message, and the receiving device that has received the participation message as a transfer destination; A relay device provided. Between a transmitting apparatus including a transmitting terminal or another upper relay apparatus capable of transmitting data from the transmitting terminal and a receiving apparatus including a receiving terminal or another lower relay apparatus to which the receiving terminal is connected In a relay device used as a relay device that forms a transmission route by sending and receiving a participation message by a multicast protocol in
Upon receiving a participation message from another relay device in the lower vicinity, transmission route information for specifying the other relay device up to the transmission device is received in the participation message to receive the desired data from the transmission device. If included, according to the received transmission route information, to the other relay device in the selected upper neighbor, at least from the other relay device in the upper neighbor in the received transmission route information to the transmitting device Transmission route formation management means (1) for generating and sending a participation message including transmission route information;
Transfer information for storing, as the data transfer source, another relay device in the upper neighbor that has transmitted the participation message by the transmission route formation management means, and as another transfer device in the lower neighbor that has received the participation message A relay device comprising storage means (4).   Policy storage means (3) for storing other relay devices in the upper neighbor to which the self message should be transmitted in response to an instruction from the outside, and the transmission route formation management means 3. The relay apparatus according to claim 2, wherein when the transmission route information is not received from the relay apparatus, a participation message is transmitted to another relay apparatus in the upper neighborhood stored in the policy storage unit. Between a transmitting apparatus including a transmitting terminal or another upper relay apparatus capable of transmitting data from the transmitting terminal and a receiving apparatus including a receiving terminal or another lower relay apparatus to which the receiving terminal is connected In a relay method of forming a transmission route by a multicast protocol with n relay devices,
A transmission route that identifies the n relay devices on the transmission route between the transmitting device and the receiving device that desires data from the transmitting device as the n = 1st relay device closest to the receiving device. A preparatory stage for receiving information from outside and storing it in a policy storage means;
The n = 1st relay device nearest to the receiving device receives the participation message including the transmission route information for receiving the data from the transmitting device from the receiving device, and selected n = A participation message including transmission route information identifying at least the remaining n-2 relay devices is generated and transmitted to a second relay device, and the receiving terminal is set as the data transfer destination, Storing the relay device as a transfer source in its own transfer information storage means,
The k (2-n-1) th relay device receives a participation message including transmission route information for identifying at least nk relay devices from the k-1th relay device, and is selected based on the transmission route information. A participation message including transmission route information for specifying the remaining n−k−1 relay devices is generated and transmitted to the k + 1th relay device, and the k−1th relay device is transferred to the data transfer destination. Storing the k + 1-th relay device as a transfer source in its own transfer information storage means, and sequentially performing these operations in the k = 2-k = n-1th relay device;
the n-th relay device receives a participation message from the (n-1) -th relay device, and stores it in its own transfer information storage means with the (n-1) -th relay device as the transfer destination and the transmission device as the transfer source; ,
Each of the first to n-th relay devices receives the data in order and transfers the data with reference to the transfer information of its own transfer information storage means;
A relay method characterized by comprising: Between a transmitting apparatus including a transmitting terminal or another upper relay apparatus capable of transmitting data from the transmitting terminal and a receiving apparatus including a receiving terminal or another lower relay apparatus to which the receiving terminal is connected In the relay method of forming a transmission route by a multicast protocol with n relay devices in order to receive the desired data from the transmitting device,
Preparation for receiving from outside information identifying the upper neighboring relay device in each relay device from n = 1 to n−1 for forming the transmission route for receiving the data and storing it in the policy storage means Stages,
Each of the relay devices from n = 1st relay device to (n−1) th receives the participation message from the lower neighbor receiving device or relay device in turn, and stores the higher-order memory stored in its own policy storage means. A relay method comprising: a step of sending a participation message to a neighboring relay device, and the n-th relay device receiving the participation message from the (n-1) -th relay device to form the transmission route. . Between a transmitting apparatus including a transmitting terminal or another upper relay apparatus capable of transmitting data from the transmitting terminal and a receiving apparatus including a receiving terminal or another lower relay apparatus to which the receiving terminal is connected A relay device used to form a transmission route according to a multicast protocol,
When forming the transmission route between the transmitting device and the receiving device that desires the data from the transmitting device, a transmission quality of a request or a specific quality parameter for forming the transmission route specified from the outside Policy storage means (3) for storing information for satisfying the request if there is a request to secure the request,
Associated network information storage means (2) for storing routing information for specifying neighboring and associated networks and other relay apparatuses connecting them;
The participation message including the identification information for specifying and receiving the data from the transmission device is received from the reception device or other lower neighboring relay devices, and based on the identification information, the policy storage means Information and the routing information in the associated network information storage means, and when the other relay device in the upper neighbor is selected with priority given to the information stored in the policy storage means, the other relay in the selected upper neighbor If the information that is requested to another relay device higher than the other relay devices in the upper neighbor is included in the policy storage means when referred to the device, the request is requested to the other relay device in the higher order. Transmission route formation management means (1) for generating a participation message including the information to be transmitted and the identification information and transmitting the message to another relay device in the upper neighbor,
The transmission route formation management unit transmits the participation message as another relay device in the upper neighbor, and the transfer device receives the participation message as the transfer destination. A relay device comprising transfer information storage means (4) for storing. When the transmission route formation management means is connected to itself with a transmission device that transmits the data specified by the identification information with reference to the information in the policy storage means and the routing information in the association network information storage means 7. The relay apparatus according to claim 6, wherein when the determination is made, the transmission apparatus is set as a transmission source, and the transfer information storage means stores another lower-layer relay apparatus in the lower neighbor that has received the participation message as a transfer destination.

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