JP2006191468A - Packet relay method, and packet relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize load reduction and high speed of a packet relay processing in an explicit multicast system. <P>SOLUTION: A packet analysis part 105 analyses a packet in a flow inherent information acquisition part 1051, and if it is the same flow, the part acquires the flow inherent information which becomes the same value. When the relay processing information corresponding to the flow inherent information is stored in a cache memory 109, the packet relay processing is performed using the relay processing information. When the correspondent relay processing information is not stored, a route table search part 106 searches a unicast route table for non-delivered recipient address, determines transmission interface information, carries out packet reproduction if necessary, performs change of header information, and performs relay processing of the packet. And, the device writes in the transmission interface information, and a change processing result of the header information including control information of the IP header and the explicit multicast system in the cache memory 109 as the relay processing information. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an explicit multicast packet relay method and a packet relay apparatus that perform distribution by describing distribution destinations of a plurality of recipients in a packet.

  In the packet transmission of the explicit multicast method, in a multicast communication in which a packet including communication data is delivered from a single sender to a plurality of receivers, a plurality of recipient addresses (destination addresses or payloads) in a packet option header or payload ( This is a packet relay method in which a sender explicitly designates a node that can receive a packet by describing an address indicating the destination of each receiver). For example, the sender in the explicit multicast system describes the addresses of all recipients in the option header and payload after the IP header of the packet and sends them out. In this specification, a packet in the explicit multicast method is simply referred to as a packet.

Here, two examples of the conventional packet relay method are shown.
(First conventional packet relay processing method)
When a packet arrives, a packet relay apparatus (hereinafter referred to as a router) that supports the explicit multicast method searches its own unicast route table for each recipient address in the packet. If the outgoing interface is different for each recipient address, the router duplicates the packet for the outgoing interface and outputs the packet to the corresponding outgoing interface. At this time, for each packet sent from the sending interface, the router considers that the address of the recipient other than the recipient address with the same sending interface from the result of the unicast routing table search has been delivered, and has been delivered. Is added or deleted from the packet.

  At this time, depending on the explicit multicast method, the destination address of the IP header of the packet to be transmitted by the router may be the address of the recipient who has already been delivered. In this case, the router selects one of the addresses of recipients other than the recipient address regarded as delivered (hereinafter referred to as an undelivered recipient), and rewrites it as the destination address of the IP header. In this way, the router prevents the occurrence of loops and duplicate delivery in packet delivery by repeating the above-described series of processing for undelivered recipient addresses as packet relay processing.

  With the above mechanism, in the explicit multicast method, packets can be multicast to all receivers designated by the sender. In this specification, the packet relay processing method described above is referred to as a first conventional packet relay processing method. As a representative explicit multicast method, there are Explicit Multicast (XCAST) methods described in Patent Document 1 and Non-Patent Document 1.

  However, in the first conventional packet relay processing method, since the unicast route table search processing is performed for undelivered recipient addresses for each arriving packet, the overhead increases and the load of packet relay processing increases. In addition, there is a problem that the speed cannot be increased.

(Second conventional packet relay processing method)
In order to solve the problem in the first conventional packet relay processing method, packet relay processing methods described in Patent Document 2 and Non-Patent Document 2 have been proposed. In this packet relay processing method, the sender of the packet generates an identifier that is unique to the sender, and the identifier is described in the packet for transmission. Next, when the packet arrives at the router, in addition to the first conventional packet relay processing method, the sender's source address, the identifier described in the packet, and the search result of the unicast route table for the packet itself (router) To the cache memory. Thereafter, when a packet having the same flow as the packet arrives, the search result of the unicast route table in the cache memory is used, and the packet relay process is compared with the first conventional packet relay process method. Reduce overhead. In this specification, the packet relay processing method described in Patent Document 2 and Non-Patent Document 2 described above is referred to as a second conventional packet relay processing method.

  However, in the second conventional packet relay processing method, the sender needs to describe an identifier that is unique to the sender in the packet, and the second conventional packet relay processing method is used for a packet that does not have an identifier described therein. Is not applicable. In addition, in the basic specification of the XCAST system, which is a typical explicit multicast system, an area for describing an identifier in an option header is prepared as a channel identifier, but the description of the identifier at the time of packet transmission at the sender is as follows. It is optional, and 0 is specified when no identifier is described. Therefore, the application range of the second conventional packet relay processing method is limited, the speed of packet relay processing for packets not assigned with an identifier cannot be increased, and packet relay processing is performed when a large number of packets without identifiers arrive. There is a problem that the processing load increases.

JP 2000-354063 A JP 2001-36583 A Internet-Draft (draft-ooms-xcast-basic-spec-05.txt) Internet-Draft (draft-ooms-cl-multicast-02.txt)

  The present invention has been made in view of the above circumstances, and can reduce the overhead at the time of packet relay processing, and can reduce the load and speed up of the packet relay processing even when the identifier is not given to the packet. An object of the present invention is to provide a packet relay method and a packet relay device that can be realized.

  A first aspect of the present invention is a packet relay method for relaying an explicit multicast packet that clearly specifies the recipient of the packet by describing the addresses of a plurality of recipients in the packet. Analyzing the packet and obtaining flow specific information having the same value if the flow is the same, and performing relay processing of the packet based on the relay processing information corresponding to the acquired flow specific information And.

  As a result, a packet relayed once based on the flow-specific information of the packet and the relay processing information corresponding to the flow-specific information, so that a packet that has been relayed once, even if no identifier is assigned to the packet , It is possible to relay the packet by omitting the unicast routing table search process for packets that arrive thereafter. For this reason, the overhead in packet relay processing can be reduced, and packet relay processing can be performed at high speed.

  In addition, the present invention secondly, in the first packet relay method, determining whether or not relay processing information corresponding to the acquired flow specific information is held in a storage unit; A step of relaying the packet using the relay processing information when the relay processing information corresponding to the flow specific information is held.

  As a result, when the flow specific information of the packet is acquired and the relay processing information corresponding to the flow specific information is held, the packet is subjected to the relay processing using the relay processing information, so that the identifier is assigned to the packet. Even if it is not assigned, if the flow is the same as that of a packet that has been relayed once, it is possible to relay the packet by omitting the unicast route table search process for packets that arrive thereafter. For this reason, the overhead in packet relay processing can be reduced, and packet relay processing can be performed at high speed.

  Third, the present invention provides the second packet relay method, wherein in the step of relaying the packet, transmission interface information is acquired from the relay processing information, and the packet A duplication process and a process for changing the header information of the packet are performed, and the packet after the process is output according to the transmission interface information.

  In addition, according to the fourth aspect of the present invention, in the second or third packet relay method described above, when the relay processing information corresponding to the flow specific information is not held, an undelivered recipient address is processed. The unicast routing table is searched, the sending interface information is determined based on the search result, and the packet duplication processing and the packet header information changing processing are performed as necessary. Outputting a packet according to the transmission interface information.

  The fifth aspect of the present invention is the fourth packet relay method according to the present invention, and further stores relay processing information including at least the transmission interface information in a storage unit in association with the flow specific information. It shall have steps.

  The present invention sixthly relates to the fifth packet relay method, wherein the relay processing information further includes information on a result of changing the header information of the packet.

  Further, the present invention seventhly, in the first packet relay method, the step of inputting the acquired flow specific information to a hash function and acquiring a hash value corresponding to the flow specific information; A step of determining whether or not the relay processing information corresponding to the hash value is held in the storage unit; and when the relay processing information corresponding to the hash value is held, the packet is transmitted using the relay processing information. Performing the relay process.

  When the flow specific information of the packet is acquired, the flow specific information is input to the hash function, the hash value corresponding to the flow specific information is acquired, and the relay processing information corresponding to the hash value is held. In addition, by performing relay processing of the packet using this relay processing information, even if the identifier is not given to the packet, if it is the same flow as the packet that has been relayed once, the packet that arrives thereafter The packet can be relayed by omitting the search processing of the unicast route table for. In addition, by using the hash value, the presence / absence of relay processing information can be determined more simply and at high speed. For this reason, the overhead in packet relay processing can be reduced, and packet relay processing can be performed at high speed.

  Eighthly, according to the present invention, in the seventh packet relay method, in the step of relaying the packet, transmission interface information is acquired from the relay processing information, and the packet A duplication process and a process for changing the header information of the packet are performed, and the packet after the process is output according to the transmission interface information.

  The ninth aspect of the present invention is the seventh or eighth packet relay method according to the present invention, wherein when the relay processing information corresponding to the hash value is not held, an undelivered recipient address is processed. A step of searching the unicast routing table and determining the sending interface information based on the search result, and performing the packet duplication processing and the packet header information changing processing as necessary, and the packet after this processing Output in accordance with the transmission interface information.

  In addition, according to the tenth aspect of the present invention, in the ninth packet relay method, the relay processing information including at least the transmission interface information is stored in the storage unit in association with the hash value. It shall have.

  In addition, according to the present invention, in the eleventh aspect, in the ninth packet relay method, relay processing information including at least the transmission interface information is stored in association with the hash value and the flow specific information. It is assumed to have a step of storing in the means.

  According to the twelfth aspect of the present invention, in the tenth or eleventh packet relay method, the relay processing information further includes information on a result of changing the header information of the packet.

  In addition, according to the thirteenth aspect of the present invention, in any one of the second to twelfth packet relay methods, when an effective time is set for the relay processing information, based on the effective time, When the elapsed time since the relay processing information is stored in the storage means or the elapsed time since the relay processing information was last referenced has passed a predetermined time, the corresponding relay processing information is deleted from the storage means. It shall have steps.

  Further, according to the fourteenth aspect of the present invention, in any one of the second to twelfth packet relay methods, when the unicast route table is changed, the relay processing information is deleted from the storage means. It shall have steps.

  Further, according to the present invention, in the fifteenth aspect, the packet relay device relays an explicit multicast packet that clearly specifies the recipient of the packet by describing the addresses of a plurality of recipients in the packet. A flow specific information acquisition unit that analyzes the packet and acquires flow specific information having the same value if the flow is the same, and the packet based on the relay processing information corresponding to the acquired flow specific information Relay processing means for performing the relay processing.

  As a result, the packet relayed once based on the flow specific information of the packet and the relay processing information corresponding to the flow specific information, so that the packet that has been relayed once, even when the identifier is not given to the packet If the flow is the same, the unicast route table search process for packets arriving thereafter can be omitted and the packets can be relayed. For this reason, the overhead in packet relay processing can be reduced, and packet relay processing can be performed at high speed.

  According to the sixteenth aspect of the present invention, in the fifteenth packet relay apparatus, storage means for storing relay processing information corresponding to the flow specific information, and relay processing information corresponding to the acquired flow specific information Relay processing information determining means for determining whether or not the information is held in the storage means, and the relay processing means, when the relay processing information corresponding to the flow specific information is held, The packet is relayed using information.

  As a result, when the flow specific information of the packet is acquired and the relay processing information corresponding to the flow specific information is held, the packet is subjected to the relay processing using the relay processing information, so that the identifier is assigned to the packet. Even if it is not assigned, if the flow is the same as that of a packet that has been relayed once, it is possible to relay the packet by omitting the unicast route table search process for packets that arrive thereafter. For this reason, the overhead in packet relay processing can be reduced, and packet relay processing can be performed at high speed.

  In addition, according to the seventeenth aspect of the present invention, in the fifteenth packet relay apparatus, a hash value acquisition unit that inputs the acquired flow specific information to a hash function and acquires a hash value corresponding to the flow specific information And storage means for storing relay processing information corresponding to the hash value; and relay processing information determination means for determining whether or not the relay processing information corresponding to the hash value is held in the storage means, When the relay processing information corresponding to the hash value is held, the relay processing means performs relay processing of the packet using the relay processing information.

  When the flow specific information of the packet is acquired, the flow specific information is input to the hash function, the hash value corresponding to the flow specific information is acquired, and the relay processing information corresponding to the hash value is held. In addition, by performing relay processing of the packet using this relay processing information, even if the identifier is not given to the packet, if it is the same flow as the packet that has been relayed once, the packet that arrives thereafter The packet can be relayed by omitting the search processing of the unicast route table for. In addition, by using the hash value, the presence / absence of relay processing information can be determined more simply and at high speed. For this reason, the overhead in packet relay processing can be reduced, and packet relay processing can be performed at high speed.

  According to the present invention, overhead at the time of packet relay processing can be reduced, and even when a packet is not assigned an identifier, load reduction and speedup of the packet relay processing can be realized.

  In the following embodiment, a specific example will be described assuming an XCAST method as an explicit multicast method, but the present invention does not depend on the XCAST method, and can be applied to packet forwarding of other multicast methods. It is a thing. The packet relay method and the packet relay apparatus of the present invention can be applied to a router in a network such as IPv4 or IPv6.

  The first aspect of the present embodiment is characterized in that in the explicit multicast system, a storage area (cache memory) for storing relay processing information based on flow specific information is provided. When an unknown packet in the explicit multicast scheme arrives, packet relay processing is performed according to the first conventional packet relay processing method described above, and packet relay processing information is associated with flow specific information in a storage area (cache memory). After that, when a packet having the same flow arrives, packet relay processing is performed using relay processing information corresponding to the flow specific information.

  As a result, if the flow is the same as that of the packet that has been relayed once, the search processing of the unicast route table for the undelivered recipient address of the packet that arrives thereafter can be omitted. Therefore, the overhead in the first conventional packet relay processing method can be reduced, the packet relay processing can be reduced, and the packet relay processing can be performed at high speed.

  Further, according to such a packet relay processing method, compared with the second conventional packet relay processing method described above, the second conventional packet relay processing method is provided with a cache mechanism for relay processing information based on flow specific information. Even when the identifier used in the packet relay processing method is not given to the packet, the packet relay processing can be speeded up.

  The second aspect of the present embodiment is characterized in that in the explicit multicast method, a storage area (cache memory) for storing relay processing information based on a hash value is provided. When an unknown packet in the explicit multicast method arrives, packet relay processing is performed according to the first conventional packet relay processing method described above, a hash value is obtained from the flow specific information of the packet, and the packet relay processing information is converted into a hash value. Is stored in the storage area (cache memory) in association with each other, and when a packet of the same flow arrives thereafter, the packet relay processing is performed using the relay processing information corresponding to the hash value acquired from the flow specific information of the packet. Do.

  Thereby, the same effect as the packet relay processing method in the first aspect can be obtained, and the storage area (cache memory) can be compared with the sequential relay processing information search using only the flow specific information in the first aspect. ) The search time for the relay processing information can be shortened.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the packet relay apparatus according to the first embodiment of the present invention. The packet relay apparatus 100 according to the first embodiment includes a plurality of input interfaces (I / F) 101-1 to 101-n, a packet receiving unit 102, a packet relay processing switching unit 103, and an explicit multicast packet relay processing. Unit 104, unicast route table 110, other packet processing unit 111, packet transmission unit 112, and a plurality of transmission interfaces (I / F) 113-1 to 113-n. The explicit multicast packet relay processing unit 104 includes a packet analysis unit 105, a routing table search unit 106, a packet replication / header processing unit 107, a memory control unit 108, and a cache memory 109. The Further, the packet analysis unit 105 includes a flow specific information acquisition unit 1051.

  Packets arriving at the input interfaces (I / F) 101-1 to 101-n are received by the packet receiving unit 102 and supplied to the packet relay processing switching unit 103. The packet relay processing switching unit 103 supplies an explicit multicast packet to the explicit multicast packet relay processing unit 104 and supplies other packets to the other packet processing unit 111.

  In the explicit multicast packet relay processing unit 104, the packet analysis unit 105 analyzes an explicit multicast packet. Here, the flow specific information acquisition unit 1051 in the packet analysis unit 105 acquires flow specific information having the same value if the flow is the same. The flow unique information acquisition unit 1051 uses, as flow unique information, for example, a destination address / source address in an IP header, a flow label, a destination port number / source port number in a UDP header, and an explicit multicast described in an option header. All recipient addresses (recipient addresses) which are control information of the system, a flag indicating delivery completion, a port number explicitly designated for each recipient to receive a packet, and the like are acquired.

  Next, the packet analysis unit 105 inquires of the memory control unit 108 whether or not the relay processing information corresponding to the flow specific information is stored in the cache memory 109. That is, the packet analysis unit 105 has functions of a flow specific information acquisition unit and a relay processing information determination unit. At this time, the explicit multicast packet relay processing unit 104 differs in processing method depending on whether or not the relay processing information corresponding to the flow specific information is stored in the cache memory 109. Here, a case where the relay processing information corresponding to the flow specific information is held in the cache memory 109 is described as a processing method 1-1, and a case where the relay processing information is not held is described as a processing method 1-2. Is described below.

  (Processing Method 1-1): When the relay processing information corresponding to the flow specific information is held in the cache memory 109 for the packet in the explicit multicast method input to the packet relay device 100, the packet analysis unit 105 acquires transmission interface information from this relay processing information. When only one transmission interface is specified by the transmission interface information, the packet is transferred from the packet analysis unit 105 to the corresponding transmission interface among the transmission interfaces 113-1 to 113-n via the packet transmission unit 112. Output.

  If there are two or more transmission interfaces according to the content of the transmission interface information, the packet is transmitted from the packet analysis unit 105 to the packet duplication / header processing unit 107. The packet replication / header processing unit 107 performs packet replication for the transmission interface based on the relay processing information. Then, as header information change processing, for each copied packet, a recipient address other than the recipient address with the same sending interface is regarded as delivered, and a delivery completed marking is given. When the destination address of the IP header is the address of a recipient who has already been delivered, one is selected from the recipient addresses that have not been delivered and set as the destination address of the IP header. Then, the packet after the header information change processing is output from the packet duplication / header processing unit 107 to the corresponding transmission interface among the transmission interfaces 113-1 to 113-n via the packet transmission unit 112.

  (Processing method 1-2): If the relay processing information corresponding to the flow specific information is not held in the cache memory 109 for the packet in the explicit multicast method input to the packet relay device 100, packet analysis The unit 105 transmits the packet to the routing table search unit 106.

  The routing table search unit 106 searches the unicast routing table 110 for each undelivered recipient address in the packet, and determines the sending interfaces 113-1 to 113-n to be output for each undelivered recipient address. decide. As a result of searching the unicast route table 110, when only one transmission interface is specified, the packet is associated with one of the transmission interfaces 113-1 to 113-n from the packet analysis unit 105 via the packet transmission unit 112. Output to the sending interface.

  If there are two or more transmission interfaces according to the search result of the unicast route table 110, the packet is transmitted from the packet analysis unit 105 to the packet replication / header processing unit 107. The packet replication / header processing unit 107 performs packet replication for the transmission interface based on the route search result. Then, as header information change processing, for each copied packet, a recipient address other than the recipient address with the same sending interface is regarded as delivered, and a delivery completed marking is given. When the destination address of the IP header is the address of a recipient who has already been delivered, one is selected from the recipient addresses that have not been delivered and set as the destination address of the IP header. Then, the packet after the header information change processing is output from the packet duplication / header processing unit 107 to the corresponding transmission interface among the transmission interfaces 113-1 to 113-n via the packet transmission unit 112.

  At this time, the routing table search unit 106 and the packet duplication / header processing unit 107 search the unicast routing table 110 for undelivered recipient addresses in the packet, and the IP header performed for each duplicated packet. Then, the header information change processing result including the control information in the explicit multicast method is written into the cache memory 109 via the memory control unit 108 as the relay processing information together with the flow specific information of the packet. The relay processing information is stored in association with the flow specific information.

  In the processing method 1-1 and the processing method 1-2, the memory control unit 108 processes a reference request and a write request to the cache memory 109 using the flow specific information as an argument. As described above, the packet analysis unit 105, the routing table search unit 106, the packet duplication / header processing unit 107, and the memory control unit 108 realize the function of the relay processing means. In addition, the cache memory 109 has a function of a storage unit.

  FIG. 2 is an explanatory diagram showing the contents of the cache memory of the packet relay device according to the first embodiment of the present invention. As shown in FIG. 2, the cache memory 109 stores a cache entry including flow specific information and its relay processing information. In addition, an effective time is set and stored for this cache entry. The memory control unit 108 deletes, from the cache memory 109, the cache entry based on the flow specific information that has passed the valid time and the relay processing information. Thereby, the capacity of the cache memory 109 can be saved.

  In addition, each time the memory control unit 108 receives a packet in the explicit multicast method that is input to the packet relay device 100, the memory control unit 108 determines the cache entry valid time in the cache memory 109 and the cache entry valid time based on the relay processing information. Extend. Thereby, it is possible to keep the cache entry in the cache memory 109 for the packet input within a predetermined time.

  Further, the memory control unit 108 monitors the unicast route table 110 and deletes the cache entry holding the flow specific information and the relay processing information in the cache memory 109 when the unicast route table is changed. Thus, packet relay processing according to the latest unicast route can be performed.

FIG. 3 is a flowchart showing the procedure of the packet relay method by the operation of the packet relay device according to the first embodiment of the present invention.
When the packet is received, the flow specific information acquisition unit 1051 in the packet analysis unit 105 acquires the flow specific information of the received packet (step S11). Next, the packet analysis unit 105 searches through the memory control unit 108 whether the relay processing information corresponding to the acquired flow specific information is stored in the cache memory 109 (step S12).

  When the relay processing information corresponding to the flow specific information is stored in the cache memory 109, the packet analysis unit 105 acquires the relay processing information (step S13). Then, the packet analysis unit 105 determines whether the acquired relay processing information includes two or more transmission interfaces (step S14).

  If there are two or more transmission interfaces, the packet duplication / header processing unit 107 performs packet duplication for the transmission interface described in the relay processing information acquired in step S13 on the received packet. . Then, for each copied packet, the header information including IP header and control information in the explicit multicast method is changed from the relay processing information acquired in step S13, and the packet after the header information change processing is packet copied. / Output from the header processing unit 107 to the corresponding transmission interface (step S15).

  On the other hand, when there is one outgoing interface, the explicit multicast packet relay processing unit 104 does nothing for the received packet, performs normal unicast routing with reference to the IP header, and performs packet analysis. The data is output from 105 to the corresponding transmission interface (step S16). Depending on the explicit multicast method, some processing may be performed on control information in the IP header or the explicit multicast method.

  Also, when the relay processing information corresponding to the flow specific information is not stored in the cache memory 109, the routing table search unit 106 uses the unicast route for each undelivered recipient address described in the received packet. The table is searched to determine a sending interface to be output for each undelivered recipient address (step S17). Then, the packet analysis unit 105 determines whether there are two or more transmission interfaces in the route search result (step S18).

  Here, when there are two or more transmission interfaces, the packet replication / header processing unit 107 performs packet replication for the transmission interfaces. Then, an IP header necessary for each copied packet and header information change processing including control information in the explicit multicast method are performed. At this time, the transmission interface information determined based on the search result of the unicast routing table, and the header information change processing result including the IP header and the control information in the explicit multicast method performed for each copied packet, As the relay processing information, it is written in the cache memory 109 together with the packet flow specific information. The relay processing information is stored in association with the flow specific information. Then, the packet after the header information change process is output from the packet duplication / header processing unit 107 to the corresponding transmission interface (step S19).

  On the other hand, when there is one transmission interface, the explicit multicast packet relay processing unit 104 does nothing for the received packet and performs normal unicast routing with reference to the IP header. Depending on the explicit multicast method, some processing is performed on the transmission interface information determined based on the search result of the unicast route table or header information such as the IP header and control information in the explicit multicast method. There is. As described above, when any processing is performed on the transmission interface information and the header information, the processing result is written in the cache memory 109 together with the flow specific information as relay processing information (step S20). The relay processing information is stored in association with the flow specific information.

  4 to 6 are diagrams illustrating an example of a storage format of relay processing information. The first example shown in FIG. 4 is an example in which the relay processing information is composed of a set of sending interface information and a recipient address corresponding to the sending interface. The second example shown in FIG. 5 is an example in which the relay processing information is composed of a set of sending interface information and element numbers in a list of packet recipient addresses. In the third example shown in FIG. 6, the relay processing information is composed of a set of transmission interface information and a header image of a packet including control information in the explicit multicast method when output to the transmission interface. It is an example.

  According to the first embodiment, if the flow is the same as the packet once relayed, the search processing of the unicast route table for the packet that arrives thereafter can be omitted, and the overhead in the packet relay processing is reduced. be able to. Further, this embodiment can be applied even when an identifier is not given to a packet, and the load of the packet relay process can be reduced and the packet relay process can be performed at high speed.

(Second Embodiment)
FIG. 7 is a block diagram showing the configuration of the packet relay apparatus according to the second embodiment of the present invention. The packet relay apparatus 200 according to the second embodiment is different from the packet relay apparatus 100 according to the first embodiment shown in FIG. 1 in the configuration of the explicit multicast packet relay unit 204. In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, and description is abbreviate | omitted.

  The packet analysis unit 205 of the explicit multicast packet relay unit 204 includes a flow specific information acquisition unit 1051 and a hash function unit 2051 having a hash table using a hash function. The packet analysis unit 205 uses the flow specific information acquisition unit 1051 to acquire flow specific information having the same value for the same flow. Then, the acquired flow specific information is supplied to the hash function unit 2051, and the hash function unit 2051 refers to the hash table to acquire the hash value. Then, using this hash value, the cache memory 209 is accessed via the memory control unit 208, and it is determined whether or not the relay processing information corresponding to the hash value of the flow specific information is stored in the cache memory 209. That is, the packet analysis unit 205 has functions of a flow specific information acquisition unit, a hash value acquisition unit, and a relay processing information determination unit.

  Also in the second embodiment, as in the first embodiment, when the relay processing information corresponding to the flow specific information is held in the cache memory 209, the above processing method 1-1 is not held. In this case, the processing method 1-2 is executed. In this processing method 1-1 and processing method 1-2, the memory control unit 208 processes a reference request and a write request to the cache memory 209 using the hash value obtained from the flow specific information as an argument.

  FIG. 8 is an explanatory diagram showing the contents of the cache memory of the packet relay apparatus according to the second embodiment of the present invention. As shown in FIG. 8, the cache memory 209 stores a cache entry including a hash value, flow specific information, and relay processing information. In addition, an effective time is set and stored for this cache entry. The memory control unit 208 deletes, from the cache memory 209, the flow specific information whose valid time has passed and the cache entry based on the relay processing information. Thereby, the capacity of the cache memory 209 can be saved.

  In addition, each time the memory control unit 208 receives a packet in the explicit multicast method that is input to the packet relay apparatus 200, the memory control unit 208 sets the valid time of the cache entry based on the flow specific information of the packet in the cache memory 209 and the relay processing information. Extend. Thereby, it is possible to keep the cache entry in the cache memory 209 for the packet input within a certain time.

  Further, the memory control unit 208 monitors the unicast route table 110 and deletes the cache entry holding the flow specific information and the relay processing information in the cache memory 209 when the unicast route table is changed. Thus, packet relay processing according to the latest unicast route can be performed.

FIG. 9 is a flowchart showing the procedure of the packet relay method by the operation of the packet relay device according to the second embodiment of the present invention.
When a packet is received, the flow specific information acquisition unit 1051 in the packet analysis unit 205 acquires the flow specific information of the received packet. Then, in the hash function unit 2051, the flow specific information is input to the hash function of the hash table to acquire a hash value (step S21). Next, the packet analysis unit 205 searches through the memory control unit 208 whether the relay processing information corresponding to the acquired hash value of the flow specific information is stored in the cache memory 209 (step S22).

  Note that even if different flow-specific information is input to the hash function, the same hash value may be obtained. Therefore, when the relay processing information is referred to only by the hash value, the relay processing information different from the actual correspondence relationship is obtained. Sometimes referred to. Therefore, as shown in FIG. 8, the cache memory 209 stores the flow specific information together with the hash value and the relay processing information, and when referring to the relay processing information from the hash value, it differs by checking the flow specific information. Avoid referencing relay processing information.

  When the relay processing information corresponding to the hash value of the flow specific information is stored in the cache memory 209, the packet analysis unit 205 acquires the relay processing information (step S23). Then, the packet analysis unit 205 determines whether or not the acquired relay processing information includes two or more transmission interfaces (step S24).

  If there are two or more transmission interfaces, the packet replication / header processing unit 107 performs packet replication for the transmission interface described in the relay processing information acquired in step S23 on the received packet. . Then, for each duplicated packet, the header information including IP header and control information in the explicit multicast method is changed from the relay processing information acquired in step S23, and the packet after the header information change processing is packet copied. The data is output from the header processing unit 107 to the corresponding transmission interface (step S25).

  On the other hand, when there is one transmission interface, the explicit multicast packet relay processing unit 204 does not perform anything on the received packet, performs normal unicast routing with reference to the IP header, and performs packet analysis. Output from 205 to the corresponding sending interface (step S26). Depending on the explicit multicast method, some processing may be performed on the control information in the IP header or the explicit multicast method.

  In addition, when the relay processing information corresponding to the hash value of the flow specific information is not stored in the cache memory 209, the routing table search unit 106 determines for each undelivered recipient address described in the received packet. The unicast route table is searched to determine a sending interface to be output for each undelivered recipient address (step S27). Then, the packet analysis unit 205 determines whether there are two or more transmission interfaces in the route search result (step S28).

  Here, when there are two or more transmission interfaces, the packet replication / header processing unit 107 performs packet replication for the transmission interfaces. Then, an IP header necessary for each copied packet and header information change processing including control information in the explicit multicast method are performed. At this time, the transmission interface information determined based on the search result of the unicast routing table, and the header information change processing result including the IP header and the control information in the explicit multicast method performed for each copied packet, As the relay processing information, it is written in the cache memory 209 together with the hash value of the packet and the flow specific information. The relay processing information is stored in association with the flow specific information. Then, the packet after the header information change processing is output from the packet duplication / header processing unit 107 to the corresponding transmission interface (step S29).

  On the other hand, when there is one transmission interface, the explicit multicast packet relay processing unit 204 does not perform anything on the received packet, and performs normal unicast routing with reference to the IP header. Depending on the explicit multicast method, some processing is performed on the transmission interface information determined based on the search result of the unicast route table or header information such as the IP header and control information in the explicit multicast method. There is. As described above, when any processing is performed on the transmission interface information or the header information, the processing result is written in the cache memory 209 together with the hash value and the flow specific information as relay processing information (step S30). The relay processing information is stored in association with the flow specific information.

  According to the second embodiment, as in the first embodiment, if the flow is the same as that of a packet that has been relayed once, the search processing of the unicast route table for packets that arrive thereafter can be omitted. Overhead in packet relay processing can be reduced. Further, this embodiment can be applied even when an identifier is not given to a packet, and the load of the packet relay process can be reduced and the packet relay process can be performed at high speed. In the second embodiment, by using the hash value, it is possible to perform the determination process (relay process information search process) of the presence / absence of the relay process information corresponding to the flow specific information more easily and at high speed.

  As described above, according to the present embodiment, even when the identifier is not given to the packet, if the flow is the same as the packet once relayed, the search of the unicast route table for the packet that arrives thereafter is performed. Processing can be omitted. As a result, the overhead in the packet relay process can be reduced, the load of the packet relay process can be reduced, and the speed of the packet relay process can be increased.

  The present invention can reduce the overhead at the time of packet relay processing, and has the effect of reducing the load and speeding up of packet relay processing even when no identifier is assigned to the packet. Therefore, it is useful for a packet relay method and packet relay apparatus of the explicit multicast method in which a delivery destination of a plurality of recipients is described in a packet for delivery.

1 is a block diagram showing a configuration of a packet relay device according to a first embodiment of the present invention. Explanatory drawing which shows the content of the cache memory of the packet relay apparatus which concerns on the 1st Embodiment of this invention The flowchart which shows the procedure of the packet relay method by operation | movement of the packet relay apparatus based on the 1st Embodiment of this invention. The figure which shows the 1st example of the storage format of the relay process information which concerns on this embodiment The figure which shows the 2nd example of the storage format of the relay process information which concerns on this embodiment The figure which shows the 3rd example of the storage format of the relay process information which concerns on this embodiment The block diagram which shows the structure of the packet relay apparatus which concerns on the 2nd Embodiment of this invention. Explanatory drawing which shows the content of the cache memory of the packet relay apparatus which concerns on the 2nd Embodiment of this invention The flowchart which shows the procedure of the packet relay method by operation | movement of the packet relay apparatus based on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,200 Packet relay apparatus 101 Input interface 102 Packet receiving part 103 Packet relay process switching part 104,204 Explicit multicast packet relay process part 105,205 Packet analysis part 106 Routing table search part 107 Packet duplication / header process part 108,208 Memory control unit 109, 209 Cache memory 110 Unicast route table 111 Other packet processing unit 112 Packet transmission unit 113 Transmission interface 1051 Flow specific information acquisition unit 2051 Hash function unit

Claims (17)

A packet relay method for relaying a packet of an explicit multicast method in which a sender clearly describes a recipient of the packet by describing addresses of a plurality of receivers in the packet,
Analyzing the packet and obtaining flow specific information having the same value for the same flow;
Performing relay processing of the packet based on relay processing information corresponding to the acquired flow specific information;
A packet relay method comprising: The packet relay method according to claim 1,
Determining whether or not relay processing information corresponding to the acquired flow specific information is held in a storage unit;
When relay processing information corresponding to the flow specific information is held, the relay processing of the packet using the relay processing information;
A packet relay method comprising: The packet relay method according to claim 2, wherein
In the step of relaying the packet, the transmission interface information is acquired from the relay processing information, the packet duplication processing and the packet header information changing processing are performed as necessary, and the packet after this processing is A packet relay method for outputting according to sending interface information. The packet relay method according to claim 2 or 3, wherein
A step of searching a unicast route table for an undelivered recipient address when relay processing information corresponding to the flow specific information is not held, and determining transmission interface information based on the search result; ,
Performing a duplication process of the packet and a change process of the header information of the packet as necessary, and outputting the packet after the process according to the transmission interface information;
A packet relay method comprising: The packet relay method according to claim 4, further comprising:
A packet relay method comprising a step of storing relay processing information including at least the transmission interface information in a storage unit in association with the flow specific information. The packet relay method according to claim 5,
The packet relay method, wherein the relay processing information further includes information on a change processing result of header information of the packet. The packet relay method according to claim 1,
Inputting the acquired flow specific information into a hash function to acquire a hash value corresponding to the flow specific information;
Determining whether or not the relay processing information corresponding to the hash value is held in the storage means;
When relay processing information corresponding to the hash value is held, relaying the packet using the relay processing information; and
A packet relay method comprising: The packet relay method according to claim 7,
In the step of relaying the packet, the transmission interface information is acquired from the relay processing information, the packet duplication processing and the packet header information changing processing are performed as necessary, and the packet after this processing is A packet relay method for outputting according to sending interface information. The packet relay method according to claim 7 or 8,
When the relay processing information corresponding to the hash value is not held, searching the unicast route table for undelivered recipient addresses, and determining the sending interface information based on the search results;
Performing a duplication process of the packet and a change process of the header information of the packet as necessary, and outputting the packet after the process according to the transmission interface information;
A packet relay method comprising: The packet relay method according to claim 9, further comprising:
A packet relay method comprising a step of storing, in a storage unit, relay processing information including at least the transmission interface information in association with the hash value. The packet relay method according to claim 9, further comprising:
A packet relay method comprising a step of storing in a storage means relay processing information including at least the transmission interface information in association with the hash value and the flow specific information. The packet relay method according to claim 10 or 11,
The packet relay method, wherein the relay processing information further includes information on a change processing result of header information of the packet. The packet relay method according to any one of claims 2 to 12,
When a valid time is set for the relay processing information,
Based on the valid time, when the relay processing information has been stored in the storage means, or when the elapsed time since the relay processing information was last referenced has passed a predetermined time, the corresponding relay processing information A packet relaying method comprising the step of erasing from the storage means. The packet relay method according to any one of claims 2 to 12,
A packet relay method comprising a step of deleting the relay processing information from the storage means when there is a change in a unicast route table. A packet relay device that relays a packet of an explicit multicast scheme that clearly specifies a recipient of the packet by a sender describing addresses of a plurality of recipients in the packet,
A flow-specific information acquisition unit that analyzes the packet and acquires flow-specific information having the same value if the same flow;
Relay processing means for relaying the packet based on relay processing information corresponding to the acquired flow specific information;
A packet relay device comprising: The packet relay device according to claim 15,
Storage means for storing relay processing information corresponding to the flow specific information;
Relay processing information determining means for determining whether or not relay processing information corresponding to the acquired flow specific information is held in the storage means;
The relay processing means is a packet relay device that relays the packet using the relay processing information when the relay processing information corresponding to the flow specific information is held. The packet relay device according to claim 15,
Hash value acquisition means for inputting the acquired flow specific information into a hash function and acquiring a hash value corresponding to the flow specific information;
Storage means for storing relay processing information corresponding to the hash value;
Relay processing information determining means for determining whether or not the relay processing information corresponding to the hash value is held in the storage means;
When the relay processing information corresponding to the hash value is held, the relay processing means performs the packet relay processing using the relay processing information.

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