WO2008058428A1

WO2008058428A1 - A specific source multicasting method

Info

Publication number: WO2008058428A1
Application number: PCT/CN2006/003101
Authority: WO
Inventors: Yancong Ma; Qinxue Li
Original assignee: Zte Corporation
Priority date: 2006-11-17
Filing date: 2006-11-17
Publication date: 2008-05-22
Also published as: CN101480010A; CN101480010B

Abstract

A specific source multicasting method applied in the network comprising a layer 2 switch and a layer 3 switch, includes the following steps: dividing the VLAN resource specially for the specific source multicast in the layer 2 switch and dividing the work domain of the VLAN resource; adding the (S,G) channel in the work domain; matching the IGMP protocol message sent from the port with the (S,G) channel in the VLAN resource; and according to the match, reforming the message and forwarding the message to the layer 3 switch.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a specific source multicast method, which relates to

IGMPv3 (Internet Group Member Protocol version 3) is implemented on a Layer 2 switch device. BACKGROUND OF THE INVENTION Multicast technology enables efficient transmission from a single point to multiple points, effectively saving bandwidth resources compared to unicast and broadcast. Multicast functions can be easily used to provide value-added services such as Internet TV, online direct broadcast, distance education, telemedicine, Internet radio, and real-time video conferencing. The multicast models defined in Internet Multicast Management Protocol Version 1 and Version 2 (IGMPvl and IGMPv2) are all Any Source Multicast (ASM) models. This model supports any number of senders, any one of the terminals. The host (or router) can send data to a host group, even though it may not be a member of the group. In any source multicast system, there are some inherent defects, such as address allocation and access control issues, which cannot prevent address conflicts between multiple applications. Once a receiver joins a multicast group, it will forward any source to the multicast group. The data. Even if a multicast source obtains a multicast group address to send data, there is no guarantee that no other source will use this address.

Defined in IGMPv3 is the Specific Source Multicast (SSM) model. The service provided by the SSM to the network layer is a "channel" that uses the destination IP address of the specific multicast (G) and the source IP address. The address S (Source Address) is "channel", and the recipient can receive these datagrams by joining the (S, G) channel. SSM mitigates and compensates for the shortcomings of ASM. In the address allocation, the specific source multicast defines the IP address G and the source IP address S (S, G), and the G is extended by S, for example (SI, G) and (S2, G), although they have the same The group address G, but represents two channels by S1 and S2, respectively. This avoids the problem of globally assigning multicast addresses of specific source multicast destinations. Each multicast source can separately handle address conflicts between multiple channels it creates. In access control, when a receiver joins a (S, G) channel, it can only receive data sent by the source S. Instead, any host can send data to an ASM host multicast group. When a sender selects an (S, G) channel to send data, the specific source multicast is automatically guaranteed not to There are other senders that send data on one channel. This makes it much more difficult to send spam on a particular source multicast channel than on any source multicast group. In the process of processing a well-known multicast source, the SSM only needs to maintain a source-based forwarding tree. The shared tree system in the multicast routing protocol is no longer needed. This will greatly reduce the multicast routing structure. Complexity, on the other hand, can directly deploy a multicast network. Layer 3 routers can control the forwarding of multicast packets. In most cases, multicast packets inevitably pass through some Layer 2 switching devices, such as Layer 2 switches, especially in a LAN environment. If a Layer 2 switch does not process multicast packets, it floods all interfaces of the Layer 2 switch, causing waste of resources and affecting performance. IGMP Snooping is usually used to solve this problem in any source multicast system. During the IGMP snooping process, the receiving host sends an IGMP member report message. When the Layer 2 switch passes the Layer 2 switch, the Layer 2 switch listens to the message and records the relationship between the group member and the interface. When a multicast packet is received, the multicast packet is forwarded only to the interface that has the member of the group. After the Layer 2 switch processes the IGMP protocol packet, it forwards the protocol packet to the Layer 3 device interface intact. However, in the specific source multicast according to IGMPv3, the IGMP multicast member management mechanism is designed for the Layer 3, and the Layer 3 router can control the forwarding of multicast packets. For a Layer 2 switch, especially in a LAN environment, Layer 2 switches in a specific source multicast cannot process multicast packets, causing flooding to all interfaces of the Layer 2 switch, resulting in waste of resources and impact on performance. . Therefore, there is a need for a solution for implementing a specific source multicast on a network including a Layer 2 switch, which can solve the problems in the related art described above. SUMMARY OF THE INVENTION The present invention is directed to a specific source multicast method for solving the problem that a specific source multicast cannot be implemented on a layer 2 switch in the related art. According to an aspect of the present invention, a specific source multicast method for a network including a Layer 2 switch and a Layer 3 switch is provided, comprising the steps of: dividing a VLAN resource into a specific source multicast dedicated in a Layer 2 switch, and The working area of the VLAN resource is divided; the (S, G) channel is added in the working domain; the IGMP protocol packet sent by the port is matched with the (S, G) channel in the VLAN resource; and the packet is reassembled according to the matching situation. And forwarded to the Layer 3 switch. In the specific source multicast method described above, adding the (S, G) channel in the working domain includes the following steps: Specifying a source port and a receiving port in the working domain, where the source port is a program source port in the VLAN resource, and the receiving port Is the section view port in the VLAN resource. In the specific source multicast method described above, the matching includes the following steps: If the message is consistent with the (S, G) channel, the port is added to the (S, G) channel; if the message conflicts with the (S, G) channel, Then delete the port in the (S, G) channel. In the foregoing specific source multicast method, determining whether the packet and the (S, G) channel are consistent includes the following steps: parsing all channel request information in the packet, and then (S, G) channel configured on the layer 2 switch Matches to determine whether the port is a traffic port or a traffic-free port. If it is a traffic port, it is the same, otherwise it is a conflict. In the specific source multicast method described above, parsing all the channel request information in the packet includes the following steps: Decomposing the packet in units of group records to obtain channel request information, where each channel of the request is configured as a request type {R , (S, G) }, mark the request type as {Join, (S, G) } and {Leave, (S, G) }. In the above specific source multicast method, the judgment criterion of {Join, (S, G) } is as follows: If the record type is MODE-IS-INCLUDE or CHANGE-TO-INCLUDE-MODE, the message contains (S, G) If the record type is MODE—IS—EXCLUDE or CHANGE—TO—EXCLUDE—MODE, the message does not contain (S, G) items; the record type is ALLOW_NEW—SOURCES, and the current filter mode is INCLUDE, then the message contains ( S, G); The record type is BLOCK_OLD_SOURCES, and the current filter mode is EXCLUDE, then the message contains (S, G) entries. In the above specific source multicast method, the judgment criterion of {Leave, (S, G) } is as follows: If the record type is MODE JS—INCLUDE or CHANGE_TO—INCLUDE_MODE, the message does not contain (S, G) Item; record type is MODE-IS-EXCLUDE or CHANGE-TO-EXCLUDE-MODE, the message does not contain (S, G) items; record type is ALLOW_NEW__SOURCES, the current filter mode is EXCLUDE, then the message contains (S, G); the record type is BLOCK_OLD_SOURCES, and the current filter mode is INCLUDE, then the message contains (S, G) entries. In the specific source multicast method described above, adding a port includes the following steps: When the channel request information of the port is {Join, (S, G) }, the (S, G) channel is searched, if it does not match, the {Join, (S, G ) } will be discarded; if it matches, add a port in the (S, G) channel. In the specific source multicast method described above, deleting a port includes the following steps: When the channel request information of the port is {Leave, (S, G) }, the port is deleted in the (S, G) channel. In the specific source multicast method described above, reassembling the IGMP protocol packet and forwarding it to the Layer 3 switch includes the following steps: The Layer 2 switch encapsulates the IGMP protocol packet into multiple MODE-ISJNCLUDE records [G, SI], [G, S2], [G, S3] .·· .., and then forward these records to the Layer 3 switch through different channels. Through the above technical solution, the present invention achieves the following technical effects: This document provides a method for implementing a Layer 2 switch IGMPv3, which is a "Dominated IGMPv3 Snooping" method. The implementation method performs effective analysis and processing on IGMP v3 packets based on the multicast deployment plan of the Layer 2 and Layer 3 devices, and then splits, converts, records, and transmits the packets to the upper-layer routers. This method is no longer a simple monitoring and recording. It needs to monitor and process IGMPv3 packets according to the deployment of multicast traffic. The method effectively implements the support of the Layer 2 switch for IGMPv3, so that the Layer 2 switch can have a strong specific source multicast function under the existing conditions. Other features and advantages of the invention will be set forth in the description which follows, and The objectives and other advantages of the invention will be realized and attained by the <RTI BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 shows a flow chart of a specific source multicast method according to the present invention; FIG. 2 shows a flow chart of a specific source multicast method according to an embodiment of the present invention. The present invention provides a specific source multicast implementation method. As shown in FIG. 1 , the method includes the following steps: Step S102: Divide a VLAN resource into a specific source multicast in a Layer 2 switch, and divide the VLAN resource. a working domain; step S104, adding a (&, G) channel in the working domain; step S106, matching an IGMP protocol packet sent by the port with the (S, G) channel in the VLAN resource; and step S108, according to the matching In the case, the message is reassembled and forwarded to the Layer 3 switch. Step S104 may include the following steps: Specifying a source port and a receiving port in the working domain, where the source port is a program source port in the VLAN resource, and the receiving port is a program viewing port in the VLAN resource. The matching may include the following steps: If the message is consistent with the (S, G) channel, then the port is added to the (S, G) channel; if the message and the (S, G) channel conflict, then in the (S, G) channel Delete the port. Determining whether the packet is consistent with the (S, G) channel may include the following steps: parsing all channel request information in the packet, and then matching with the (S, G) channel configured on the layer 2 switch, thereby determining that the port is The flow port is still a no-flow port. If it is a flow-through port, it is the same, otherwise it is a conflict. Parsing all the channel request information in the message may include the following steps: Decomposing the message in units of group records to obtain channel request information, wherein each channel of the request is configured as a request type {R, (S, G)}, Request types are labeled {Join, (S, G) } and {Leave, (S, G) }.

The judgment criterion of {Join, (S, G) } can be as follows: Record type is MODE—IS—INCLUDE or CHANGE—TO—INCLUDE—MODE, then the message contains (S, G); Record type is MODE—IS— EXCLUDE or CHANGE_TO_EXCLUDE_MODE, the message does not contain (S, G) items; the record type is ALLOW_NEW_SOURCES, the current filter mode is INCLUDE, then the message contains (S, G) items; The type is BLOCK_OLD_SOURCES, and the current filtering mode is EXCLUDE, then the message contains (S, G) items.

The judgment criterion of {Leave, (S, G) } can be as follows: If the record type is MODE-IS-INCLUDE or CHANGE_TO-INCLUDE-MODE, the message does not contain (S, G) items; the record type is MODE-IS — EXCLUDE or CHANGE— TO— EXCLUDE— MODE , the message does not contain ( S, G) items; the record type is ALLOW_NEW_SOURCES, the current filter mode is EXCLUDE, Then the message contains (S, G) items; the record type is BLOCK_OLD_SOURCES, and the current filtering mode is INCLUDE, then the message contains (S, G) items. Adding a port may include the following steps: When the channel request information of the port is {Join, (S, G) }, the (S, G) channel is searched, and if it does not match, the {Join, (S, G) } will be thrown. Discard; if matching, add a port in the (S, G) channel. Deleting a port can include the following steps: When the channel request information of the port is {Leave, (S, G) }, the port is deleted in the (S, G) channel. Reassembling IGMP protocol packets and forwarding them to Layer 3 switches can include the following steps: Layer 2 switches encapsulate IGMP protocol packets into multiple MODE-IS-INCLUDE records [G, SI], [G, S2], [G, S3 ] , . . . . . , then forward these records to the Layer 3 switch through different channels. The present invention will be described in detail below with reference to FIG. 2 and in conjunction with the embodiments. As shown in FIG. 2, the method includes the following steps: Step S202. Divide some VLAN (Virtual Local Area Network) resources into multicast for the Layer 2 device. And divide the working domain of the multicast VLAN. Step S204. In the working domain of the multicast VLAN, add several (S, G) channels. Step S206. Match the IGMP protocol packet sent by the port with the (S, G) channel in the multicast VLAN. In step S208, if they are consistent, the port is added to the (S, G) channel. In step S210, if there is a conflict, the port is deleted in the (S, G) channel. Step S212. In the multicast VLAN, the packet is reassembled to the Layer 3 device according to the matching with the (S, G) channel.

Generally, a Layer 2 device identifies a data stream and exchanges data through a VLAN ID (VID) and a destination MAC (Destination Media Access Control) address (DA) in data exchange. In this switching system, the source address of the data stream cannot be distinguished in essence, and the SSM service cannot be directly provided. The present invention divides two parts of VLAN resources on the Layer 2 switch, and a part of the multicast data stream uses a multicast VLAN, and the Layer 3 switching device connected to the Layer 2 switch passes the multicast stream through the multicast VLAN. It is sent to the uplink port of the Layer 2 switch; another part of the VLAN is given to the (S, G) channel. Each (S, G) channel corresponds to an SGVLAN, and the SGVALN is assigned to the (S, G) channel of a specific source address and group address through the network management configuration. The present invention corresponds to the (S, G) channel multicast stream and the layer 2 forwarding stream (VID, DA) by configuring the (S, G) channel. In the networking application, each multicast VLAN corresponds to the same VLAN interface of the Layer 3 device. The (S, G) channel on the Layer 2 switch belongs to a multicast VLAN. Channels, such as (Sl, G), (S2, G), (S3, G), these same group address G, different source addresses Sl, S2, S3 channels are configured in different multicast VLANs, such (SI, G ), (S2, G), (S3, G) belong to multicast VLAN 1, multicast VLAN 2, and multicast VLAN 3. IGMPv3 report packets and query packets are processed during IGMPv3 packet processing. The terminal host connected to the Layer 2 switch will send a report message to indicate the (S, G) channel that you want to join or leave. A complete group record mainly consists of three parts, group record type, one group address (G), and one column source address (SI, S2, S3). The types of IGMPv3 group records are as follows:

1. The current state is the inclusion mode (MODE_IS JNCLUDE)

2. The current state is the exclusion mode (MODE_IS—EXCLUDE)

3. Filter mode to include mode (CHANGE_TO_INCLUDE_MODE)

4. Switch the filter mode to the exclusion mode (CHANGE TO - EXCLUDE - MODE)

5. Source address list transformation, allowing new source addresses ( ALLOW - NEW - SOURCES )

6. Source address list conversion, masking the old source address (BLOCK_OLD_SOURCES) In different recording modes, the group address and the source address list correspond to the (S, G) channel's permissions for the port are different, whether it is What combination, for the (S, G) channel on the Layer 2 switch, only two results are produced. One is that the port allows the traffic in the (S, G) channel to be received, for the (S, G) channel. The traffic port; the second is that the port is prohibited from receiving traffic in the (S, G) channel, which is the forbidden port of the (S, G) channel. Therefore, the core problem of the Layer 2 switch in the processing of IGMPv3 report packets is to resolve all (S, G) channels in the packets and then match the (S, G) channels configured on the Layer 2 switch. Whether the port is a flow port or a no-flow port, if it is a flow port, it needs to be at (S, G) The port is added to the channel, otherwise the port is deleted. After processing the channel according to the report message, the Layer 2 switch reassembles the message and encapsulates the message record [G, SI, S2, S3...] into several records [G, SI ], [G, S2], [G, S3], etc., then forward these records to the third layer through different multicast VLANs according to the membership of the (S, G) channel in the Layer 2 switch in the multicast VLAN. device. Specifically, when the Layer 2 switch receives the multicast address as G from the host, and the source address list is MODE_IS-INCLUDE of S1, S2, and S3, for example, the Layer 2 switch receives an IGMP report message from the host. Record, record type is MODE-ISJNCLUDE, multicast address is G, source address list is SI, S2, S3, if the port is (SI, G), (S2, G), (S3, G) The port will be decomposed into three MODE-IS-INCLUDE, (SI, G) records will be sent to the multicast VLAN1 interface, (S2, G) records will be sent to the multicast VLAN2 interface, (S3, G) records will be Send to the multicast VLAN3 interface. Such (SI, G), (S2, G), (S3, G) multicast streams will be sent to the Layer 2 switch through different VLANs 1, 2, 3, for the same group address data stream, VLAN1, VLAN2, VLAN3 Corresponding to different VLAN IDs, so that different source IDs can be distinguished by different VLAN IDs, and the correspondence between (S, G) and (VID, G) is realized. Implement SSM control of Layer 2 switches. In the implementation, the source port and the receiving port are first specified in the multicast working domain, where the source port is a program source port in the multicast VLAN, and for the layer 2 switch, it is usually a port associated with the layer 3 router; It is the program viewing port, usually the program out port, so the packets of the non-source port and the receiving port will be ignored. Then, the report message is decomposed in units of group records, and the request information of the port for several channels is obtained. Each channel is configured as a request type (R: Request) plus channel information (S, G), abbreviated as {R, (S , G) }, the request type has two types: Join and Leave, which are labeled {Join, (S, G) W{Leave, (S, G) }. The judgment criteria of {Join, (S, G) } in the message are as follows:

1. The record type is MODE—IS—INCLUDE or CHANGE—TO—INCLUDE—MODE, and the message contains (S, G) items;

2. The record type is MODE_IS—EXCLUDE or CHANGEJTO—EXCLUDE—MODE, and the message does not contain (S, G) items; 3. The record type is ALLOW-NEW-SOURCES, the current filter mode is INCLUDE, and the message contains (S, G) items; _ _;

4. The record type is BLOCK_OLD_SOURCES, and the current filter mode is EXCLUDE, the message contains (S, G) items; the judgment criteria of {Leave, (S, G) } in the message are as follows:

1. The record type is MODE—ISJNCLUDE or CHANGE—TOJNCLUDE—MODE, and the message does not contain (S, G) items;

2. The type of record is MODE—IS—EXCLUDE or CHANGE—TO—EXCLUDE—MODE, and the message does not contain (S, G) items;

3. The record type is ALLOW-NEW_SOURCES, the current filter mode is EXCLUDE, and the message contains (S, G) entries;

4. The record type is BLOCK_OLD_SOURCES, and the current filter mode is INCLUDE, and the message contains (S, G) items. The specific process is as follows: Step 1. Decompose the IGMPv3 report received by the receiving port in units of group records. , get a series of {Join, (S, G) ^p {Leave, (S, G) }, and then process them one by one. Step 2. When {Join, (S, G) } is processed, search for the (S, G) channel configured in each multicast VLAN configured on the Layer 2 switch. If there is no match, the {Join, (S, G) } will be discarded; if it matches, add the port in the Layer 2 (S, G) forwarding channel; then in the (S, G) dependent multicast VLAN, reorganize the record and send it to the source port; Step 3. When When {Leave, ( S, G ) } is processed, the port is deleted in the Layer 2 (S, G) forwarding channel; then, in the (S, G) subordinate multicast VLAN, the report message is modified, and the deletion is established. S, G) The entry message is sent to the source port. During the processing of IGMPv3 Query messages, the Layer 2 switch processes IGMPv3 Query messages from all source ports. The received query messages will be sent to all receiving ports in the multicast VLAN. As can be seen from the above description, the present invention achieves the following beneficial effects. This document provides a method for implementing a Layer 2 switch IGMPv3, which is a "Dominated IGMPv3 Snooping" method. On the basis of any source multicast IGMP Snooping, the implementation method effectively analyzes and processes IGMP v3 packets based on the multicast deployment plan of the Layer 2 and Layer 3 devices, splits, converts, records, and delivers them to the upper-layer routers. This method is no longer a simple monitoring and recording. It needs to monitor and process IGMPv3 packets according to the deployment of multicast traffic. The method effectively implements the support of the Layer 2 switch for IGMPv3, so that the Layer 2 switch can have a strong specific source multicast function in the existing device. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A specific source multicast method for a network including a Layer 2 switch and a Layer 3 switch, comprising the steps of:

Allocating VLAN resources to the specific source multicast in the Layer 2 switch, and dividing the working domain of the VLAN resource;

Adding (S, G) channels in the working domain;

Matching the IGMP protocol packet sent by the port with the (S, G) channel in the VLAN resource;

The packet is reassembled and forwarded to the Layer 3 switch according to the matching situation.

2. The specific source multicast method according to claim 1, wherein the adding (S, G) channel in the working domain comprises the following steps:

A source port and a receiving port are defined in the working domain, where the source port is a program source port in the VLAN resource, and the receiving port is a program viewing port in the VLAN resource.

3. The specific source multicast method according to claim 2, wherein the matching comprises the following steps:

If the 4艮 and (S, G) channels are identical, then the port is added to the (S, G) channel;

If the 4艮 and (S, G) channels collide, the port is deleted in the (S, G) channel.

The specific source multicast method according to claim 3, wherein determining whether the message and the (S, G) channel are consistent comprises the following steps:

Parsing all the channel request information in the packet, and then matching with the (S, G) channel configured on the layer 2 switch, so as to determine whether the port is a traffic port or a no-flow port, if it is a traffic flow The ports are the same, otherwise they are conflicts. The specific source multicast method according to claim 4, wherein the parsing all channel request information in the packet comprises the following steps:

Decomposing the message in units of group records to obtain the channel request information, wherein each channel of the request is configured as a request type {R, (S, G) }, and the request type is respectively marked as {Join, (S , G) {Leave, (S, G) }. The specific source multicast method according to claim 5, wherein the criterion of {Join, (S, G) } is as follows:

If the record type is MODE-IS-INCLUDE or CHANGE_TO-INCLUDE-MODE, then the message contains (S, G); if the record type is MODE-IS_EXCLUDE or CHANGE_TO-EXCLUDE-MODE, then The message does not contain (S, G) items;

"3⁄4 recording type is ALLOW-NEW_SOURCES, the current filtering mode is INCLUDE, then the message contains (S, G) items;

The record type is BLOCK_OLD_SOURCES, and the current filter mode is EXCLUDE, then the message contains (S, G) entries. The specific source multicast method according to claim 5, wherein the criterion of {Leave, (S, G) } is: ^下下:

If the recorded type is MODE—IS—INCLUDE or CHANGE—TO—INCLUDE—MODE, then the 4艮 text does not contain (S, G) items; the recorded type is MODE—IS—EXCLUDE or CHANGE—TO—EXCLUDE— MODE , then the ^ = 艮 text does not contain ( S , G) items;

"^ has been recorded as ALLOW-NEW_SOURCES, and the current filtering mode is EXCLUDE, then the message contains (S, G) items;

The record type is BLOCK_OLD_SOURCES, and the current filter mode is INCLUDE, then the message contains (S, G) entries.

8. The specific source multicast method according to claim 5, wherein the step of adding the port package is as follows:

Searching for the (S, G) channel when the channel request information of the port is {Join, (S, G) }, if the channel does not match, the {Join, (S, G) } Will be discarded; £ as matched, add the port in the (S, G) channel.

9. The specific source multicast method according to claim 5, wherein deleting the port comprises the following steps:

When the channel request information of the port is {Leave, (S, G) }, the port is deleted in the (S, G) channel.

10. The Source-Specific Multicast method according to claim 5, wherein the recombinant ^ ¹ Gen IGMP protocol and forwards to the three switches comprising the steps of:

The Layer 2 switch encapsulates the IGMP protocol message into multiple MODE-IS-INCLUDE records [G, SI], [G, S2], [G, S3], ... and then through different channels. These records are forwarded to the Layer 3 switch.