JP2003234760A - Packet transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packet transfer device in which the load on processing can be reduced by simplifying processing of a received packet to the discard thereof. <P>SOLUTION: A multicast packet 219 sent from a transmitting terminal 212 finally reaches a receiving terminal 214 from a transmitting side IP router device 213 through a receiving side IP router device 216, passes a receiving side router device 217 and arrives at a receiving terminal 215. When starting transmitting specific stream data from the transmitting terminal 212, a receiving request presence/absence confirming device 220 makes one of the receiving terminals 214 and 215 requesting the reception of the data request the preparation of a transmission route. The IP router device 213, 216 or 217 writes the information of a packet not to be transferred not to prepare such a transmission route in a hardware management table and when the relevant packet is received, it is discarded by a hardware engine. Therefore, the decision on the discard for each of received packet and the burden on discarding processing can be reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet transfer device for transferring or discarding a received packet, and more particularly to a packet transfer device effective for transferring stream data.

[0002]

2. Description of the Related Art Stream-related data such as voice and moving images can be transferred to a plurality of host computers due to changes in the communication environment such as the construction of networks that enable the communication of relatively large amounts of data and the constant connection to the Internet. Services to send are beginning to be provided. In particular, when multicast communication is used, it is possible to realize a broadcast communication service in which a broadcasting station transmits sounds and images from one terminal to many terminals.

By the way, most of the multicast communications currently performed are realized by using UDP. UDP
Is a protocol in which a packet sent by the sender does not receive a response corresponding to the reception from the recipient who receives the packet. A series of multicast packets sent out using UDP is transferred to a plurality of recipients after being accommodated in a packet transfer device such as an IP router.

Currently, in many packet transfer devices, the routing process and transfer process for a received packet are performed by the CPU according to its control program (software).
It is realized by a general-purpose control unit such as (central processing unit). The routing process is a process of analyzing the header of the received packet and selecting a transfer route, and the transfer process is a process of forwarding the received packet to the transfer route selected in the routing process. Therefore, the packet transfer device needs to repeatedly perform the routing process and the transfer process each time a multicast packet is received when performing the transfer process for the stream data.

[0005]

By the way, when attention is paid to an arbitrary packet transfer device located between a sender of a multicast packet and a receiver at the end, this packet transfer device is located on a route where the receiver of the multicast communication does not exist. It is necessary to discard the received multicast packet. On the other hand, the sender of the multicast packet or the packet transfer device on the upstream side does not receive a reply to the packet to that effect even if the individual receiver does not request the packet due to the use of UDP. Therefore, these persons will continue to transmit packets toward the packet transfer device of interest this time. As a result,
When performing transfer processing for stream data,
Each time the packet transfer device receives a multicast packet, it individually determines whether or not to discard the packet for each transfer destination path, and when discarding the packet, performs the processing.

Conventionally, the above-mentioned control unit of the packet transfer apparatus has performed such a process related to discarding by a control program or software. For this reason, although the normal packet has a small processing load for discarding, the stream-type data is confirmed and discarded until the end of transmission of the series of packets to the receiver who does not want to receive the stream data. Such processing will be continued for each packet. Therefore, there is a problem that the load of the control unit of the packet transfer device is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a packet transfer device capable of simplifying the process of discarding a received packet and reducing the processing load.

[0008]

According to a first aspect of the present invention, (a) a specific packet for confirming whether or not the receiving terminal of each receiving terminal that may receive the specific packet desires to receive the specific packet. A means for confirming whether or not you want to receive
(B) Transfer-side route determining means for determining a packet-transfer-side route in which all of the receiving terminals which are determined not to receive by the receiving desire presence confirmation means or the receiving terminals which do not want to receive the specific packet are all; (C) Registration means for registering the discrimination result of the transfer side route discrimination means,
(D) Packet discarding means for discarding packets, and (e)
Packet transfer means for transferring a packet to a destination, and (to)
Specific packet receiving means for receiving a specific packet,
(G) When the specific packet receiving means receives a specific packet, the destination is a route in which all the receiving terminals which are determined not to receive by referring to the registering means or the receiving terminals which do not want to receive the specific packet are addressed. A packet that delivers a specific packet to the packet discarding means while delivering a specific packet destined to the receiving terminal desiring to receive the specific packet or the route where the receiving terminal desiring to receive the specific packet exists to the packet forwarding means. The packet transfer device is equipped with a delivery means.

That is, according to the first aspect of the invention, the specific packet reception desired presence / absence confirming means desires to receive the specific packet from each receiving terminal which may receive the specific packet forming the stream data or the like. I try to confirm whether or not. Then, the transfer side route discrimination means discriminates and registers the route on the packet transfer side in which all the receiving terminals which are not desired to be received by the reception desired presence confirmation means or the receiving terminals which do not want to receive the specific packet are registered. The means registers the determination result of the transfer side route determination means. Therefore, when the specific packet receiving means receives a specific packet, the registration means is referred to and the receiving terminals determined not to receive or the receiving terminals which do not want to receive the specific packet are all the destinations. The specific packet to be transferred is passed to the packet discarding means and is discarded as long as this specific packet exists at the transfer destination. In this way, after registration in the registration means, unnecessary destination specific packets are delivered to and discarded by the packet discard means without any special processing, so that the load on the control part of the packet transfer device is reduced. be able to.

According to the second aspect of the present invention, (a) packet receiving means for receiving a packet whose destination is any one of a plurality of specific receiving terminals or a route leading to it, and (b)
It is not necessary to distinguish the receiving terminals that do not want to receive a specific packet or the receiving terminals that do not want to receive a specific packet from all the specified receiving terminals or the routes to them, from the receiving terminals or routes other than this. Unnecessary reception information storage means for storing information, (c) packet discard means for discarding packets, (d) packet transfer means for forwarding packets to a destination, and (e) these for a plurality of specific receiving terminals. And whether or not the receiver wants to receive the specific packet, or whether all the receiving terminals that have passed the predetermined route do not want to receive the specific packet. A reception unnecessary information registration means for registering reception unnecessary information based on the confirmation result of the reception desired presence confirmation means in the reception unnecessary information storage means, and (g) packet When the receiving means receives a specific packet, whether or not it needs to be transferred is determined by the unnecessary reception information registered by the unnecessary reception information registration means, and the route without the receiving terminal desiring to receive or the receiving terminal not desiring to receive is directly determined. While receiving the specific packet destined to the packet discarding means to the packet discarding means, the receiving terminal processing for delivering the specific packet destined to the route where the receiving terminal desiring reception exists or the receiving terminal desiring reception to the packet transferring means The packet transfer device is equipped with a route selection means.

That is, according to the second aspect of the present invention, the packet receiving means receives a packet whose destination is one of a plurality of receiving terminals specified in advance or a route leading to the receiving terminal. For example, in the case where stream-based data is distributed, a specific member who has made a contract to receive each stream-based data corresponds to the specific plurality of receiving terminals. The inclusion of the packets whose destinations are not only those receiving terminals but also the routes leading to them is also applicable to the case where the individual receiving terminals are not the direct destinations. In the present invention, the unnecessary reception information storage means is provided, and, for example, a route in which all of these specific receiving terminals do not want to receive packets or receiving terminals that do not want to receive packets is the unnecessary reception information storage. The information is stored in the means as unnecessary reception information. In the case of an alternative between those who want to receive and those who do not, the person who wants to receive and the route thereof may be stored. This is because those who do not want to receive and routes are specified as those that do not belong to this. The processing route of the packet received by the packet transfer device is selected by the receiving terminal processing route selecting means. At this time, the unnecessary reception information registered by the unnecessary reception information registration means is checked. Therefore, it is possible to easily determine whether it is a packet to be discarded at the time of reception, and when discarding it, pass it to a dedicated packet discard means for discarding the packet without leaving the processing to the subsequent circuit part and Can be disposed of. That is, when packets with the same destination are continuously sent, such as stream data, the unnecessary reception information storage means stores that the packet of the destination is unnecessary at a certain point. For example, the corresponding packet among the received packets is immediately passed to the packet discarding unit for processing. As described above, according to the second aspect of the present invention, the unnecessary reception information regarding the plurality of specified receiving terminals is stored and collated, so that the route where the receiving terminal desiring to receive does not exist or the reception not desiring to receive is performed. The packet discarding means enables the packet discarding means to discard the specific packet destined for the terminal directly, thereby reducing the load on the control part of the packet transfer device.

According to a third aspect of the present invention, in the packet transfer apparatus according to the second aspect, the receiving terminal processing route selecting means directly routes a route in which there is no receiving terminal desiring to receive or a receiving terminal not desiring to receive. Specific packet,
Alternatively, it is characterized in that when there is a specific packet other than the specific packet whose destination is the receiving terminal desiring to receive or the receiving terminal desiring to receive is a direct destination, this is confirmed by the desirability confirmation means.

That is, according to the third aspect of the invention, the received specific packet is neither a target to be discarded nor a target to be actively transferred to the receiving terminal from the contents stored in the unnecessary reception information storage means. It shows how to handle the case. With respect to such a specific packet, the receiving terminal processing route selection means causes the reception desired presence / absence confirmation means to confirm. Therefore, if the specific packet of the receiving terminal or the route is discarded as the confirmation result, it is registered as the reception unnecessary information. Therefore, from now on, the selection of the specific packet and the discard by the packet discard means have a special burden. Will be done without. As a result of the confirmation, the specific packet may be a packet that the receiving terminal does not plan. For example, in the case where a plurality of specific receiving terminals are terminals of the members of the stream data described above, it is possible to continuously send specific packets for interference to the receiving terminals by masquerading as the sender of the stream data. This is the case when there are three parties. In such cases,
By assuming that these receiving terminals do not desire to receive the specific packet, the specific packet thereafter can be processed by the dedicated discarding means. Therefore,
By performing such discarding processing of the specific packet by a dedicated circuit or hardware, it is possible to minimize the influence on the original control of the packet transfer device.

According to the invention described in claim 4, in the packet transfer device according to claim 2, the unnecessary reception information registration means starts transmission of a specific packet toward any one of a plurality of specific receiving terminals or a route leading to it. When the predetermined time is set in advance, the confirmation result confirmed by the reception desired presence confirmation means before the specific packet is received by the packet reception means is registered in the reception unnecessary information storage means.

That is, in the invention described in claim 4, when the time when the transmission of the specific packet is started is predetermined, the unnecessary reception information is registered in the unnecessary reception information storage means before the specific packet is received. Is dealing with. In a communication system capable of doing this, the discarding process can be simplified not only for stream type data or such contents but also for a specific packet transmitted only once in an extreme case. It will be.

According to a fifth aspect of the present invention, in the packet transfer apparatus according to the second aspect, the desired reception presence / absence confirming means desires to receive any one of a plurality of specific receiving terminals after the transmission of the specific packet is started. It is equipped with change detection means for detecting this when a change is made as to whether or not
The reception unnecessary information registration means is characterized in that the change detected by the change detection means is registered.

That is, in the invention described in claim 5, a change in the necessity or non-desirability of reception of a specific plurality of receiving terminals that occurs after the start of the transmission of the specific packet is detected, and the detected change is received unnecessary information storage means. You are supposed to register at.
Thus, when it is detected that the unnecessary reception information used for determining whether or not the transfer is necessary based on the change at the receiving terminal side may be changed, the unnecessary reception information can be changed accordingly. For example, if a receiving terminal that receives a series of specific packets via a packet transfer device does not want to receive them, immediately discard these specific packets that will be received subsequently based on the unnecessary reception information after detecting this change. You can

According to a sixth aspect of the present invention, in the packet transfer apparatus according to the second aspect, a plurality of specific receiving terminals are provided by a contractor who contracts to receive a series of packets constituting stream-type content for each content. It is a terminal, and the reception desired presence / absence confirmation means is characterized by confirming the presence / absence of reception of a specific packet based on the presence / absence of reception of each content according to the contract of these reception terminals.

That is, the invention according to claim 6 shows one specific example of the plurality of specific receiving terminals and the desired reception presence / absence confirming means according to claim 2. The receiving terminal is adapted to receive stream-type content by contracting for each content. A receiving terminal that has a contract for the same content will receive a specific packet incorporating the specific content. In this case, the specific plurality of receiving terminals are all members who can make a contract for individual contents. In the case of this example, the reception desired presence / absence confirming means uses a conventional method of confirming which content the member desires to receive. For example, a method in which a cable television station confirms the receiver of individual broadcasts is used, and the data obtained by this is reflected in the storage content of the reception unnecessary information storage means as reception unnecessary information. By connecting with such a confirmation means, it becomes possible to acquire or change the unnecessary reception information even if the specific packet itself is of a format that is unilaterally sent to the receiving terminal.

The invention according to claim 7 is the packet transfer apparatus according to claim 1 or 2, wherein the packet discarding means is composed of a circuit dedicated to discarding.

That is, in the invention described in claim 7, the packet discarding means is configured by a circuit dedicated to discarding, so that it is possible to eliminate the influence on other circuit parts of the transfer device. The packet discard means may be hardware dedicated to packet discard, or may be configured by software including a dedicated CPU and the like.

[0022]

DETAILED DESCRIPTION OF THE INVENTION

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows a simplified example of a multicast network provided with a packet processing device for transferring packets transmitted by multicast communication according to an embodiment of the present invention. The multicast network 211 includes a transmitting terminal 212 used by a multicast packet sender and an IP (Internet Protocol) router device 213 adjacent to the transmitting terminal 212.
And are arranged. Further, a first receiving terminal 214 and a second receiving terminal 215 used by a multicast packet receiver, and a first receiving-side IP router apparatus 216 and a second receiving-side IP router apparatus 217 which are respectively adjacent to these terminals are arranged. Has been done. The transmission terminal 212 is connected to a library 218 containing various stream system data to be incorporated in a multicast packet to be transmitted. Also, the first and second receiving terminals 214, 215
A reception desired presence / absence confirmation device 220 is connected to. The reception desire confirmation device 220 is placed in a company (not shown) which is an organization different from the company that manages the library 218, in this example, a CATV (cable television) distribution station. Then, each receiving terminal 214, 215
Whether or not the user desires to receive a specific program or content can be confirmed on the side of the device 220 for confirming whether or not there is a desire to receive by a conventionally established method. The confirmation result of the device 220 for confirming whether or not to wish to receive is normally the CAT.
Used for in-house purposes such as collecting fees for V distribution station contractors. In the present embodiment, the device 2 for confirming whether or not there is a desire to receive.
Based on this confirmation result, the 20 transmits the distribution request information 210 to each of the receiving terminals 214 and 215 in accordance with the distribution of the content that the user desires to receive. The distribution request information 210 includes one that requests creation of a distribution route for receiving distribution from the transmission terminal 212 and one that requests deletion of the distribution route. The CATV distribution station sends the distribution request information 210 to each of the receiving terminals 214, 21.
By transmitting the content to the customer, it is possible to deliver the contracted content to the corresponding receiving terminal.

The first and second receiving-side IP router devices 216 and 217 in FIG. 1 may be connected to some receiving terminals not shown, but these are omitted in this embodiment for simplification of description. Do not think about. Further, in this figure, the sending side IP router device 213 and the first and second receiving side IP router devices 216 and 217 are directly connected, but in an actual network, some packet transfer devices are provided between them. An IP router device can be arranged as

Now, the multicast network 21
In No. 1, an IP address for identifying each terminal is assigned and can be used for designating a destination or a source when transmitting an IP packet. The multicast address is incorporated into the multicast packet as information indicating the destination. The multicast address is a specific IP address for associating with an IP address assigned to a plurality of terminals that receive a specific multicast packet.

In the transmitting side IP router device 213, the first receiving side IP router device 216, and the second receiving side IP router device 217 on the multicast network 211, it is determined by RFC (Request For Comment) "2362". PIM-SM (Protocol Independent)
Multicast-Sparse Mode) is working. PIM-S
M is a routing protocol for multicast distribution between the IP router devices, and manages a distribution tree for multicast. This multicast distribution tree has a tree structure in which an IP router device operating PIM-SM is arranged, and each receiving terminal 2
Receiving terminals such as 14, 215 are connected to any of the placed IP router devices. The IP router device arranged at the apex of the multicast distribution tree is the transmitting-side IP router device 213 adjacent to the transmitting terminal 212 that transmits the multicast packet.
Further, the first and second receiving-side IP router devices 21 to which the receiving terminals such as the receiving terminals 214 and 215 are connected.
The IP router devices 6, 217 and the like act as proxy for the receiving terminal with respect to the IP router devices, such as the transmission side IP router device 213, which are arranged upstream. As a result, the multicast distribution tree according to the present embodiment has the I adjacent to the receiving terminal requesting the reception of the multicast packet.
It is designed to be created from the P router device toward the IP router device at the top.

As described above, such a multicast network 211 is used as a communication system for providing a service in which, for example, a company having the copyright of music compositions distributes these data to members. Considering an example, the transmission terminal 212 and the library 218 are arranged in a service department in a company, and the transmission terminal 212 is
A series of multicast packets 2 that incorporates stream-related data of the music held in the library 218
19 is to be created. Stream data refers to a plurality of packet data that are continuous from the beginning in the order of reproduction. For example, in the case of music stream data, by reproducing these packets from the beginning, you can listen to the music. It has become. The transmission side IP router device 213 is arranged in the communication department of the company, and is configured to transmit a series of multicast packets (stream data) 219 created from the music by the transmission terminal 212 to each reception terminal. . Also, the first and second receiving terminals 214, 215 are communication terminals such as computers provided in the member's room, so that stream-related data of a music piece can be extracted from a series of received multicast packets 219 to reproduce the music piece. It has become. These first and second receiving terminals 214, 21
As described above, the 5 members are contractors of the CATV distribution station at the same time. The same service can be provided by using a provider with which these members have a connection contract. In this case, the provider uses the first and second receiving-side IP router devices 216 and 217 to transmit the received multicast packet 219 to the corresponding communication terminals of the members.

The company providing the service is designed to provide one song each from the music genres of "pops" and "jazz" among the songs stored in the library 218, and receive this song. A multicast distribution tree is created for sending to the desired members. The multicast packet 219 transmitted from the transmission terminal 212 is a series of IP packets in which the stream data of the music of "pops" or "jazz" is divided and incorporated from the beginning. However, it is also possible to create a distribution tree separately for each genre according to the wishes of the members.

FIG. 2 shows the configuration of the IP router device arranged in the network shown in FIG. Here, the transmitting side IP router device 213 will be described, but the first and second receiving side IP router devices 216, 2
17 has the same configuration. Transmission side IP router device 213
Includes a hardware engine 221 that performs hardware processing of IP packets, and an IP forwarding (Forwardi) that performs IP header analysis and transfer processing of IP packets.
ng) processing unit 222 is provided. Hardware engine 221 and IP forwarding processing unit 222
Are respectively connected to the hardware driver 223, and are relayed to exchange various data. A protocol stack processing unit 224 that operates various protocols is provided and is connected to the IP forwarding processing unit 222. Furthermore, the hardware management table 225 managed by the hardware engine 221 and the multicast / table that is a routing table managed by the IP forwarding processing unit 222.
Forwarding entries 226 are provided. The packet received by such a transmitting side IP router device 213 is first input to the hardware engine 221.

The sending IP router 213 has a CPU
A control unit (not shown) including a storage medium such as a (central processing unit) or a ROM (Read Only Memory) is arranged, and the control unit executes a predetermined program to perform control. Is supposed to do. However, the hardware engine 221 is composed of hardware that performs a predetermined process regardless of the control unit (not shown).

Each time a packet is input, the hardware engine 221 searches the hardware management table 225 for a transfer entry or a discard entry corresponding to this packet. The transfer entry or the discard entry stores a source address, a destination address, a protocol number, a source port number, and a destination port number corresponding to the header information of the IP packet. When the information stored in the entry matches the header information of the received IP packet, the hardware engine 221 determines that the received IP packet and the entry match. As a result, if the matched entry is a transfer entry, the transfer processing of this packet is performed, and if it is a discard entry, the discard processing of this packet is performed. Information necessary for transfer processing is also stored in the transfer entry, and the hardware engine 221 uses this to perform transfer processing. If the header information does not match the entry here, the input IP packet is processed by the IP forwarding processing unit 222 via the hardware driver 223.
It is designed to output to.

The protocol stack processing unit 224 includes a PIM-SM processing unit 227 that manages a dynamic multicast distribution tree according to the PIM-SM that is a multicast protocol. In addition, the PIM-SM processing unit 22
7 receives the IP header information 228 from the IP forwarding processing unit 222. This PIM
The SM processing unit 227 includes an entry table 227T that holds the entry to be searched. In this entry, the destination address corresponding to the header information of the IP packet and the multicast distribution tree of the multicast packet in which the destination address is incorporated are directly under the source IP router device 213. Alternatively, information indicating the receiving terminal is incorporated. The control unit (not shown) of the transmission side IP router device 213 searches the entry table 227T, and if the destination address stored in the entry matches the header information of the received IP packet, the IP packet and the entry match. Then, it is designed to determine.

The multicast forwarding entry 226 manages the entry to be searched by the header information of the IP packet received by the IP forwarding processing section 222. In this entry, a source address and a destination address corresponding to the header information of the IP packet, and an output port (not shown) of the sender IP router device 213 are shown as information necessary for sending the IP packet to the next transfer destination. Information etc. are incorporated. The information necessary for sending to the next transfer destination represents the information for outputting the packet to the IP router device or the receiving terminal immediately below in the multicast distribution tree corresponding to the entry in the entry table 227T. . Therefore, a relay device that does not exist on the multicast distribution tree may be designated as the next transfer destination. When the source address and the destination address stored in the entry match the header information of the received IP packet, the control unit (not shown) of the sending IP router device 213 determines that this IP packet and the entry match. It has become.

The IP forwarding processor 222 issues a discard entry registration / deletion request 229 requesting registration or deletion of a discard entry to the hardware driver 22.
3 will be sent. Hardware driver 223
Receives the discard entry registration / deletion request 229, converts the discard entry registration / deletion request 229 into a discard entry registration / deletion request 230 which is an instruction to the hardware engine 221, and sends it to the hardware engine 221. It has become.

FIG. 3 shows a data structure of header information of an IP packet which is multicast-transferred in this embodiment. The header information 301 is IP header information and UD
It indicates a combination of P (User Datagram Protocol) header information. In the UDP header information, when the multicast transfer of this embodiment is performed, information on the UDP protocol, which is a higher protocol of the IP protocol, is stored. Generally, when performing a multicast transfer using the UDP protocol, the first or second receiving terminal 214, 215 receiving the IP packet and the transmitting terminal 212 do not directly exchange signals relating to the IP packet. It has become. This is because, when transmitting a multicast packet from a transmitting terminal to a large number of receiving terminals, exchanging signals with individual receiving terminals for IP packets to be transmitted increases the load on the transmitting terminals.

The IP header information includes a version 302 indicating the version of the Internet protocol, a header length 303 indicating the length of the IP header, a service type 304 indicating the quality request of the IP packet, and a packet indicating the length of the IP packet. A length 305, an identifier 306 used to restore the data stored by being divided into IP packets, a flag 307 indicating whether this IP packet is the first, middle, or end of the divided data, and this IP
A fragment offset 308 indicating the order in which the packets are divided, a lifetime 309 indicating the lifetime on the network, a protocol number 310 indicating the protocol of the data stored in the IP packet, and a header used to detect an error. Checksum 311 and source IP
A source address 312 indicating an address and a destination I
It is composed of a transmission destination address 313 indicating a P address. In the multicast packet 219 transmitted from the transmission terminal 212 described in FIG. 1, the specific multicast address is the destination address 3 of this header information 301.
Incorporated as 13.

Next, the data structure of the UDP header information will be described with reference to FIG. UDP header information is
A source port number 314 indicating an output port when outputting from a source device, a destination port number 315 indicating an input port when a destination device receives, a segment length 316 and UDP indicating a length of a UDP packet. It is composed of a checksum 317 used for detecting a packet error. Here, the UDP packet refers to the one in which UDP header information is added to the head of the data to be multicast-transferred, and the header information of the IP packet is further added to the head to form an IP packet. .

FIG. 4 shows the flow of processing when the sending IP router device shown in FIG. 2 receives a multicast packet and the order of creating various entries. However, the entries stored in the entry table 227T will be described later. Sender I
The multicast packet 219 received by the P router device 213 is input to the hardware engine 221. Hardware engine 221
Searches the hardware management table 225 using the header information 301 of the received multicast packet 219 (step S401). Here, header information 30
If 1 matches the entry (step S402:
Y), and further, it is determined whether or not the matched entry is a transfer entry (step S403). If the entry is for transfer (Y), the hardware engine 22
1 executes the transfer process according to the instruction of the transfer entry (step S404), and ends the process (end). If the entry is not a transfer entry (step S403:
N), the hardware engine 221 carries out the discarding process on the assumption that it matches the discarding entry (step S4).
05), the process ends (END). Step S402
If the entry does not match the entry (N), the received multicast packet 219 is output to the IP forwarding processing unit 222 via the hardware driver 223.

The control unit (not shown) of the transmission side IP router device 213 receives the header information 301 of the multicast packet 219 input to the IP forwarding processing unit 222.
Is used to search the multicast forwarding entry 226 (step S406). Source address 312 and destination address 3 of header information 301
If 13 matches the information to be searched for the entry (step S407: Y), the control unit (not shown) notifies the hardware driver 223 of the transfer entry registration request based on the matched entry, and the hardware management table The transfer entry is registered in 225 (step S408). After that, the transfer processing of the multicast packet 219 is performed according to the matched entry of the multicast forwarding entry 226 (step S409), and the processing is ended (end).

If the header information 301 does not match the entry in step S407 (N), the control unit (not shown) further searches the entry table 227T managed by the PIM-SM processing unit 227 with the header information 301 (step S410). . If there is a matching entry (step S411: Y), the entry for multicast forwarding corresponding to the multicast forwarding entry 226 is registered (step S41).
2). After that, the transfer entry is registered in the hardware management table 225 and the multicast packet 219 is transferred (steps S408 and 409), and the process ends (end). If there is no matching entry in step S411 (N), the header information 301
The hardware driver 223 is notified of the discard entry creation request added with, and the hardware management table 225
Registration of an entry for discarding is performed (step S41).
3). Then, the discarding process of the multicast packet 219 is performed (step S414), and the process ends (end).

In such a process, if there is no receiving terminal desiring to receive a series of multicast packets 219 in which a certain "jazz" music is incorporated, for example, a multicast distribution tree for distributing this music is not created. The entry table 227T has no entry. When these are received, the hardware management table 2
Until the discard entry for instructing to discard these in 25 is registered, the IP forwarding processing unit 22
It is designed to be discarded after being input in 2. However, after the discard entry for instructing the discard of the multicast packet 219 of this music is registered in the hardware management table 225, the hardware engine 221 discards the entry. Therefore, in the case of continuously discarding a series of multicast packets 219 including stream data of a certain music, after the discarding entry is registered in the hardware management table 225, the IP forwarding of the transmitting side IP router device 212 is performed. No load is imposed on the processing unit 222 by the discarding process. Therefore, the IP forwarding processing unit 22 determines the IP header analysis and transfer or discard of the first packet received first in the series of multicast packets 219.
2 and the hardware engine 221 transfers or discards the multicast packet 219 received after registration of the corresponding discard entry, thereby reducing the processing load of the control unit (not shown) of the sender IP router device 212. can do.

FIG. 5 shows the flow of processing when an IP packet incorporating a reception request or reception stop request for a specific multicast packet addressed to the PIM-SM processing section 227 is received by the IP router device 213. It represents. The control unit (not shown) of the IP router device 213 determines that the received IP packet is the PIM-SM processing unit 22.
When the IP packet is destined for No. 7, it is determined whether or not the information indicates a reception request or reception stop of a series of multicast packets specified by the multicast address (step S421). Otherwise (N), the process ends (END). If the reception request or the information indicating the reception stop is incorporated (step S421: Y), and if this indicates the reception request (step S422: Y), an entry indicating the transmission destination of the specified series of multicast packets. Exists in the entry table 227T of the PIM-SM processing unit 227 (step S423). If the corresponding entry exists (Y), the entry for adding the receiving terminal that has transmitted this reception request to the destination is changed (step S
424). Along with this change, the multicast transfer entry registered in the multicast forwarding entry 226 is also changed. After that, a transfer entry deletion request is created to request deletion of the transfer entry instructing the transfer of the specified series of multicast packets from the hardware management table 225 (step S425). The created transfer entry deletion request is transmitted to the hardware driver 223 via the IP forwarding processing unit 222 (step S426) and the processing ends (END). Hardware driver 223
Passes the transfer entry deletion request to the hardware engine 221, and deletes the corresponding transfer entry from the hardware management table 225.

If the corresponding entry does not exist in the entry table 227T of the PIM-SM processing section 227 (step S423: N), an entry is created to indicate the transfer destination of this specified series of multicast packets, The entry table 227T is registered (step S427). After that, a discard entry deletion request for creating a discard entry for instructing discard of these multicast packets from the hardware management table 225 is created (step S428). The created discard entry deletion request is transmitted to the hardware driver 223 via the IP forwarding processing unit 222 (step S429) and the processing ends (END). The hardware driver 223 passes the transfer entry deletion request to the hardware engine 221, and deletes the corresponding transfer entry from the hardware management table 225.

Further, when the information indicating the reception stop is incorporated (step S422: N), if the corresponding entry does not exist in the entry table 227T (not shown) of the PIM-SM processing section 227 (step S430:
N), the process ends (END). This is a case where the reception stop is requested for the multicast packet which has no destination, and there is no processing to be performed. The corresponding entry is this entry table 227T.
If it exists (step S430: Y), a change is made to delete the receiving terminal that has transmitted the reception stop from the transmission destination of the entry. As a result, when the destination does not exist, the entry itself indicating the destination of the specified series of multicast packets is deleted (step S431). Along with this change, the multicast forwarding entry registered in the multicast forwarding entry 226 is also changed or deleted. Thereafter, a transfer entry deletion request is created to request deletion of the transfer entry instructing the transfer of this multicast packet from the hardware management table 225 (step S432). The created transfer entry deletion request is transmitted to the hardware driver 223 via the IP forwarding processing unit 222 (step S433), and the processing ends (END). Hardware driver 223
Passes the transfer entry deletion request to the hardware engine 221, and deletes the corresponding transfer entry from the hardware management table 225.

When a receiver desires to appear in a series of multicast packets 219 in which stream system data of a music piece which has been discarded by the hardware engine 221, is incorporated, the discarding process is stopped and the reception request is received. Need to resume sending to the person. As an example of this,
Distribution request information 21 for requesting the creation of a distribution route of a series of multicast packets 219 including the music.
0 from the presence / absence confirmation device 220 of the first receiving terminal 2
The processing of the first receiving terminal 214, the first receiving-side IP router apparatus 216, and the transmitting-side IP router apparatus 213 when transmitting to the No. 14 will be described.

When the first receiving terminal 214 receives the distribution request information 210 for requesting the creation of the distribution route of the series of multicast packets 219 in which the music is incorporated, the series of the music in which the music is incorporated is correspondingly received. A packet including a reception request for requesting reception of the multicast packet 219 is created and transmitted to the first receiving-side IP router device 216. At this time, the first receiving-side IP router device 216 has already performed the discard processing of the IP packet by the hardware engine 221, so P
The entry table 227T (not shown) of the IM-SM processing unit 227 has no entry for the series of multicast packets 219 in which the music is incorporated (FIG. 5: step S423: N). Therefore, such an IP
When the packet is received, an entry indicating the multicast address incorporated in the multicast packet 219 and the first receiving terminal 214 as the destination is created and registered in the entry table 227T (FIG. 27: step S427). After that, a request is made to delete from the hardware management table 225 a discarding entry instructing the discarding of a series of multicast packets 219 in which this music is incorporated (the same figure: step S42).
8, step S429). Further, the first receiving-side IP router device 216 sends an IP packet incorporating a reception request for requesting reception of a series of multicast packets 219 in which the music is incorporated, to the transmitting-side IP router device 213.
Send to. Upon receiving this IP packet, the transmission side IP router device 213 registers an entry indicating the first reception side IP router device 216 as a transmission destination in the entry table 227T, and deletes the discard entry from the hardware management table 225. Request.

After the discarding entry is deleted from the hardware management table 225 of the transmitting side IP router 213, the discarding process is not executed even if a series of multicast packets 219 including the music is received. (FIG. 4: step S402: N). Further, the received multicast packet 219 has the PIM-S
Entry table 227T (not shown) of the M processing unit 227
There is a matching entry that is managed by (step S410, step S411: Y in the figure).
Therefore, after the entries corresponding to the multicast forwarding entry 226 and the hardware management table 225 and the forwarding entry are respectively registered (FIG. 11: step S412, step S408), the first
The transfer processing of the receiving side IP router device 216 is performed by a control unit (not shown) (step S409 in the figure).
A series of multicast packets 219 incorporating the music received thereafter are transmitted by the hardware engine 221.
Performs a transfer process to the first receiving-side IP router device 216 in accordance with the instruction of the transfer entry (in the figure: step S402: Y, step S403: Y, step S).
404). In this way, the first receiving-side IP router device 216 transmits the series of multicast packets 219 in which the transmitted music is incorporated to the first receiving terminal 21.
It is supposed to be transferred to 4. First receiving terminal 214
Can listen to the music by reproducing a series of multicast packets 219 transferred from the first receiving-side IP router device 216.

As described above, in the hardware engine 221 of the embodiment, the sending side IP router device 213 registers the discarding entry in the hardware management table 225 to perform the discarding process of a series of multicast packets 219. It is like this. The registration of the discarding entry in the hardware management table 225 is performed by a control unit (not shown), but when the hardware engine 221 starts the discarding process, the control unit (not shown) performs a series of multicast. The load can be reduced because it is not related to packet discard processing. In this way, the control unit (not shown) according to the software analyzes and transfers or discards the IP header of the received series of multicast packets 219 until the hardware can perform the transfer or discard, and all of this is performed. The processing load can be reduced as compared with the case where the control unit performs. Further, by using a circuit optimized for the discard processing of the IP packet for the hardware engine 221,
The disposal process can be optimized.

Further, in the embodiment, the transmitting side IP router device 2
In order to register the discard entry in the hardware management table 225 of No. 13, it is necessary to discard at least one multicast packet 219 having no delivery destination by the IP forwarding processing unit 222. However, when it is confirmed by the PIM-SM processing unit 227 or the like that there is no receiving terminal to be a distribution destination at the start of distribution for a specific multicast packet 219 scheduled to be distributed, a discard entry for this is set. It may be registered in the hardware management table 225 in advance. By doing so, the IP forwarding processing unit 222 at the start of distribution
It is possible to reduce the number of the multicast packets 219 to be discarded in step 1, thereby reducing the processing load of the IP forwarding processing unit 222 performed by the control unit (not shown) of the transmission side IP router device 213.

Further, in the embodiment, the data to be transmitted by multicast is stream data, but if it is a series of IP packets in which the same multicast address is incorporated, the data incorporated in each of them may be irrelevant. . Further, the stream data may be not only music but also data such as voice and moving picture, or data in which these are combined.

Possibility of modification of the invention

In the embodiment described above, the transmitting terminal 212
In this case, a multicast packet is created and transmitted assuming that there is a receiving terminal. However, the present invention can be similarly applied to the case where there is no possibility that the receiving terminal exists for the multicast packet transmitted by the sender or the transmission terminal is extremely low. As an example of such a case, a DoS (denial of service) attack in which a large number of multicast packets with no recipients are transmitted with the intention of degrading or stopping the function of the IP router device can be considered. I described in the embodiment in which a discard entry can be created for such a series of multicast packets
By using the P router device, it is possible to cause the discarding process to be performed as packets that are continuously generated with the destination other than the specific receiving terminal such as a member, and eliminate the influence on the specific receiving terminal. You can Of course, the packet transfer device such as the IP router device also performs the discarding process by the dedicated hardware or software device for discarding, so that the influence on the device main body portion or the control unit can be minimized.

[0054]

As described above, according to the first aspect of the present invention, after registration in the registration means, a specific packet of an unnecessary destination is delivered to the packet discard means without any special processing and is discarded. Therefore, it is possible to reduce the load on the control part of the packet transfer device, and it is possible to have a remarkable effect particularly in the case of stream data.

According to the second aspect of the invention, the packet transfer device such as a router is provided with the reception unnecessary information storage means, and the reception terminal processing route selection means discards the packet based on the result determined by this. Whether or not it is distributed. Therefore, the packet that is determined to be discarded at this point is immediately discarded, which not only reduces the burden of the discarding process but also continuously sends illegal packets to the same destination. Even in the case where a message is received, a quick response can be made by adding this to the unnecessary reception information storage means.

According to the third aspect of the present invention, it is possible to perform processing for a packet that is neither an object to be discarded nor actively transferred to the receiving terminal. Therefore, for example, even for a business in which the receiver sets a consideration period within a certain time from the start of receiving stream data and confirms whether or not there is a desire to continue reception during this period, the packet transfer device processing The burden can be reduced.

Further, according to the invention described in claim 4, not only can the discarding process be simplified for the packet which is transmitted only once, but also in the case of stream data, unnecessary packets are received by the recipient. Since it is not sent to any other terminal, no inconvenience due to this will occur.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a multicast network including an IP router device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an IP router device of this embodiment.

FIG. 3 is an explanatory diagram showing a data structure of header information of an IP packet in the present embodiment.

FIG. 4 is a flowchart of a process performed by the transmitting IP router device for an input multicast packet in the present embodiment.

[FIG. 5] In this embodiment, the sender IP router device is a receiver IP
7 is a flowchart of a process when an IP packet is received from the router device.

[Explanation of symbols]

210 Delivery information 212 sending terminal 213 and 502 sender IP router device 214 First Receiving Terminal 215 Second receiving terminal 216 First Receiving Side IP Router Device 217 second receiving side IP router device 218 Library 221 hardware engine 222 IP forwarding processing unit 223 hardware driver 224 Protocol stack processing unit 225 Hardware Management Table 226 Multicast forwarding entry 227 PIM-SM processing unit 227T entry table

Claims (7)

[Claims] 1. A specific packet reception presence / absence confirmation means for confirming whether or not the reception of the specific packet is desired from each receiving terminal having a possibility of receiving the specific packet, and reception by the reception presence / absence confirmation means. The transfer side route determining means for determining the route of the packet transfer side, which is the receiving terminal which is determined not to desire or the receiving terminal which does not want to receive the specific packet, and the determination result of this forwarding side route determining means are registered. Registering means for discarding the packet, packet discarding means for discarding the packet, packet forwarding means for forwarding the packet to the destination, specific packet receiving means for receiving the specific packet, and when the specific packet receiving means receives the specific packet, The receiving terminal or the specific packet of the receiving terminal which is determined not to want to receive by referring to the registration means The presence of a receiving terminal desiring to receive the specific packet or a receiving terminal desiring to receive the specific packet while passing a specific packet destined to all the routes to which the receiving terminal does not want to receive to the packet discarding means A packet transfer means for transferring a specific packet whose destination is a route to the packet transfer means. 2. A packet receiving means for receiving a packet destined to any one of a plurality of specific receiving terminals or a route to the receiving terminal, and receiving a specific packet on the specific plurality of receiving terminals or a route to them. Unnecessary information storing means for storing unneeded information that distinguishes routes that are all undesired receiving terminals or receiving terminals that do not want to receive a specific packet from other receiving terminals or routes, and packet discarding means for discarding packets A packet transfer means for transferring a packet to a destination, and whether or not these specific receiving terminals do not want to receive a specific packet, or all the receiving terminals that have passed through a predetermined route specify the specific packet. A means for confirming whether or not to receive a packet for confirming whether or not a packet is desired to be received, and a confirmation of whether or not this packet is desired to be received. Reception unnecessary information registration means for registering the reception unnecessary information in the reception unnecessary information storage means based on the confirmation result of the stage, and the reception of the necessity of transfer when the packet receiving means receives the specific packet. The reception unnecessary information registered by the unnecessary information registration means is used for determination, and a specific packet whose destination is a path where a receiving terminal that does not want to receive or a receiving terminal that does not want to receive is directly passed to the packet discarding means while receiving. A packet transfer device comprising: a route on which a receiving terminal that desires to receive, or a receiving terminal processing route selecting means that delivers a specific packet whose destination is a receiving terminal desiring to receive to the packet transferring means. . 3. The receiving terminal processing route selection means is a specific packet having a route where the receiving terminal desiring to receive does not exist or a receiving terminal not desiring to receive as a direct destination, or a receiving terminal desiring to receive the packet. 3. The packet transfer device according to claim 2, wherein when there is a specific packet other than a specific packet having an existing path or a receiving terminal desiring to receive as a direct destination, the specific packet is confirmed by the desired reception confirmation means. . 4. The reception-unnecessary-information registering means, when the time when the transmission of the specific packet is started toward any one of the plurality of specific receiving terminals or a route leading to the specific receiving terminal is predetermined, 3. The packet transfer device according to claim 2, wherein the confirmation result confirmed by the reception desired / non-existence confirming unit before being received by the packet receiving unit is registered in the reception unnecessary information storage unit. 5. The reception desire presence / absence confirming means, when the change in whether or not any one of the specific plurality of receiving terminals desires to receive after the transmission of the specific packet is started, is performed. 3. The packet transfer apparatus according to claim 2, further comprising change detection means for detecting the change, wherein the unnecessary reception information registration means registers the change detected by the change detection means. 6. The specific plurality of receiving terminals are terminals provided by a contractor who contracts for reception of a series of packets constituting stream-type content for each content, and the reception desired presence / absence confirming unit receives these receptions. The packet transfer device according to claim 2, wherein the presence or absence of reception of the specific packet is confirmed by the presence or absence of reception of each content according to the contract of the terminal. 7. The packet transfer device according to claim 1 or 2, wherein the packet discarding unit is configured by a circuit dedicated to discarding.