CN1555165A - Method of Precise Port Forwarding of IP Multicast in Layer 3 Switching - Google Patents

Abstract

Translated fromChinese

本发明提供了一种三层交换中IP组播精确端口转发的方法，包括以下步骤：1.对收到的报文保留相应的VLANID和VLAN下具体的物理端口号；2.根据报文类型及保留的VLAN ID和物理端口号生成并维护一个组播路由端口映射表，该表表项保存组播路由源地址、目的组地址、入接口VLAN ID和物理端口号及出接口VLAN ID和物理端口号列表；3.根据对应的组播路由端口映射表表项将四元组形式的组播路由项下发到转发芯片，转发芯片根据组播路由项生成入、出接口为VLAN下具体物理端口的组播转发项；4.转发芯片根据组播转发项对数据报文进行转发。本发明的方法可以对数据报文进行VLAN下端口的精确转发。

The invention provides a method for precise port forwarding of IP multicast in a three-layer exchange, comprising the following steps: 1. Reserving the corresponding VLANID and the specific physical port number under the VLAN for the received message; 2. According to the message type and the reserved VLAN ID and physical port number to generate and maintain a multicast routing port mapping table, which stores the multicast routing source address, destination group address, incoming interface VLAN ID and physical port number and outgoing interface VLAN ID and physical Port number list; 3. According to the corresponding multicast routing port mapping table entry, the multicast routing item in the form of a quadruple is sent to the forwarding chip, and the forwarding chip generates the inbound and outbound interfaces according to the multicast routing item as specific physical interfaces under the VLAN. The multicast forwarding item of the port; 4. The forwarding chip forwards the data message according to the multicast forwarding item. The method of the invention can carry out accurate forwarding of ports under the VLAN to the data message.

Description

The method that the accurate port of IP multicast is transmitted in three layers of exchange

Technical field:

The invention belongs to computer network communication field, be specifically related to the method that the accurate port of IP (internet protocol) multicast is transmitted in three layers of exchange.

Background technology:

Existing IP multicast routing protocol, as PIM-SM (sparse mode of Protocol Independent Multicast Routing Protocol) and PIM-DM (this paper only are example with PIM-SM) such as (dense modes of Protocol Independent Multicast Routing Protocol), its route entry is the four-tuple of (source, group, an iifoif) form.Wherein source is that IP address, the group in multicast packet source are the purpose multicast address, and iif is an incoming interface, and oif is the outgoing interface tabulation.Multicast protocol is issued to forwarding chip with this route entry, thereby safeguards the forwarding item of corresponding quadruple form in the forwarding chip.When receiving the multicast information message, forwarding chip is searched corresponding multicast forwarding item according to the source address and the purpose multicast address of this message.If find then carry out corresponding RPF (inverse path forwarding) and check, check by then being forwarded to corresponding outgoing interface.Otherwise report multicast protocol to handle accordingly.

Usually the going into of the multicast route entry safeguarded of multicast protocol, outgoing interface all is three layer interfaces, the going into of the forwarding item that forwarding chip is safeguarded, outgoing interface then is physical port.In three-tier switch, when certain port on the VLAN joined certain multicast group, multicast protocol can join this VLAN in the multicast route entry as one three layer interface.When this route entry is issued to forwarding chip, all physical ports of this VLAN can be joined in the corresponding forwarding item.So corresponding data message will forward from all physical ports of this VLAN, promptly transmit and to be accurate to certain concrete physical port under the VLAN.If same VLAN joins different multicast groups, then the multicast traffic stream that receives of each port in this VLAN will be multiplied, and have a strong impact on forward efficiency.

For this type of problem, the solution that has at present is that the port of needs startup multicast is respectively self-configured among the different VLAN, promptly has only a physical port among a VLAN.Though this solution has improved forward efficiency to a certain extent, the VLAN number of drawing thus is with dramatic growth, and VLAN itself has also lost meaning.

In addition, for the situation of leaf node in the PIM territory, relevant solution, i.e. an IGMPSnooping are arranged.IGMP Snooping operates in link layer, when switch is received the IGMP message, IGMPSnooping analyze the IGMP message with information, set up and safeguard the MAC multicast address at two layers, the multicast message that issues from switch is just transmitted according to the MAC multicast address later on.But this scheme is merely able to solve the interior accurately port forwarding problems of VLAN of leaf node, can not separate the interior accurately port forwarding problems of VLAN of leaf node by no means.

Summary of the invention:

The purpose of this invention is to provide the method that the accurate port of IP multicast is transmitted in a kind of three layers of exchange, realize the precise relay of IP multicast, thereby improve transmitting multicast data efficient greatly in the VLAN lower port.

The method that the accurate port of IP multicast is transmitted in three layers of exchange provided by the invention may further comprise the steps successively:

1. protocol massages and the data message of receiving kept concrete physical port number under corresponding VLAN ID and the VLAN.

2. go on foot VLAN ID and the physical port number generation that keeps and safeguard that a multicast path is by port mapping table (MPM, i.e. Mroute Port Map) according to type of message and the 1st.This table list item is preserved multicast path by source address, purpose group address, incoming interface VLAN ID and physical port number and outgoing interface VLAN ID and physical port number tabulation.

3. by the port mapping table list item multicast route entry of quadruple form is issued to forwarding chip according to the multicast path of correspondence.Forwarding chip is according to this multicast route entry generates, outgoing interface is concrete physical port under the VLAN multicast forwarding item.

4. forwarding chip carries out the forwarding of machinery to the data message according to the multicast forwarding item.Because the multicast forwarding item can be as accurate as the concrete physical port under the VLAN, so can carry out the precise relay of VLAN lower port to the data message.

Advantage of the present invention and good effect: the present invention can make to transmit and be accurate to physical port concrete under the VLAN, effectively avoids data message to forward from all of the port of VLAN, thereby improves the efficient that the IP multicast data message is transmitted greatly.During a plurality of multicast group data message, effect is more obvious in the particularly same VLAN transmission network.

Description of drawings:

Fig. 1 is a multicast forwarding item generative process among the present invention.

Embodiment:

Because forwarding chip just carries out the forwarding of machinery according to the multicast forwarding item to the data message, so multicast data message depends on the multicast forwarding item that can be accurate to the concrete port of VLAN in the forwarding chip in the precise relay of vlan port.Generate such multicast forwarding item key and be the maintenance of multicast path by port mapping table.

Multicast path at first will have concrete physical port number under the VLAN ID of receiving group protocol massages and data message and the VLAN by the maintenance of port mapping table.Three-tier switch is preserved the interface index of its three layers and two layers to the message of receiving, can obtain corresponding VLAN ID and physical port number according to three layer interface index and two layer interface index.

Multicast path is generated under following several situations by the port mapping table list item:

1.IGMP (IGMP) part generates (*, G) list item when receiving member relation report (MembershipReport);

2.PIM-SM part receives (*, G) JOIN (addings) message time generation (*, G) list item;

3.PIM-SM part receives (S, G) JOIN (addings) message time generation (S, G) list item;

4.PIM-SM generate (S, G) list item when part receives multicast data message.

Multicast path is inserted corresponding VLAN ID and physical port number after being generated by the port mapping table list item, and (*, G) list item is with (S, G) (*, G) route table items is with (S, G) relation between the route table items is identical in the relation and PIM-SM between the list item.

Multicast path by the maintenance of port mapping table list item based on following rule:

1.IGMP during part removing members (overtime, receive leave message etc.), the corresponding outgoing interface of corresponding list item is carried out deletion action;

2.IGMP part receives member relation when report, and the corresponding outgoing interface of corresponding list item is added operation;

3.PIM-SM part is when receiving PRUNE (beta pruning) message, and the corresponding outgoing interface of corresponding list item is carried out deletion action;

4.PIM-SM part is when receiving JOIN (adding) message, and the corresponding outgoing interface of corresponding list item is added operation;

5. multicast path is upgraded by the incoming interface of the port mapping table list item inlet according to data message;

6. multicast path is by being provided with timer in the port mapping table list item, thereby realizes the aging of list item;

7.VLAN the change triggers multicast path of following physical port is by the renewal of port mapping table list item.

Fig. 1 shows the generative process of multicast forwarding item.When the multicast routing table list item is issued to forwarding chip,, then search multicast path, the multicast route entry of quadruple form is issued to forwarding chip according to corresponding VLAN ID and physical port number by port mapping table if its certain outgoing interface is VLAN.Forwarding chip generates the multicast forwarding item that interface is a concrete physical port under the VLAN, and carries out the precise relay of multicast packet in the VLAN lower port according to this forwarding item.

Claims (5)

Translated fromChinese

1.三层交换中IP组播精确端口转发的方法，依次包括如下步骤：1. The method for IP multicast precise port forwarding in the three-layer exchange comprises the following steps in turn:(1)对收到的协议报文和数据报文保留相应的VLAN ID和VLAN下具体的物理端口号；(1) Reserving the corresponding VLAN ID and the specific physical port number under the VLAN for the received protocol message and data message;(2)根据报文类型及步骤(1)保留的VLAN ID和物理端口号生成并维护一个组播路由端口映射表，该表表项保存组播路由源地址、目的组地址、入接口VLAN ID和物理端口号及出接口VLAN ID和物理端口号列表；(2) Generate and maintain a multicast routing port mapping table according to the packet type and the VLAN ID and physical port number reserved in step (1), and the table entry stores the multicast routing source address, destination group address, and incoming interface VLAN ID And physical port number and outgoing interface VLAN ID and physical port number list;(3)根据对应的组播路由端口映射表表项将四元组形式的组播路由项下发到转发芯片，转发芯片根据该组播路由项生成入、出接口为VLAN下具体物理端口的组播转发项；(3) According to the corresponding multicast routing port mapping table entry, the multicast routing item in the form of a quadruple is sent to the forwarding chip, and the forwarding chip generates the incoming and outgoing interfaces according to the multicast routing item to be specific physical ports under the VLAN. Multicast forwarding item;(4)转发芯片根据组播转发项对数据报文进行机械的转发。(4) The forwarding chip mechanically forwards the data message according to the multicast forwarding item.2.如权利要求1所述的三层交换中IP组播精确端口转发的方法，其特征在于，所述步骤(1)中，所述VLAN ID和VLAN下具体物理端口号是根据三层交换机所保存的收到报文的三层和二层接口索引而获得的。2. the method for IP multicast accurate port forwarding in the three-layer exchange as claimed in claim 1, is characterized in that, in described step (1), concrete physical port number under described VLAN ID and VLAN is according to three-layer switchboard It is obtained from the saved Layer 3 and Layer 2 interface indexes of received packets.3.如权利要求1或2所述的三层交换中IP组播精确端口转发的方法，其特征在于，所述步骤(2)中，组播路由端口映射表项在以下几种情况下生成：3. the method for IP multicast precise port forwarding in the three-layer exchange as claimed in claim 1 or 2, it is characterized in that, in described step (2), multicast routing port mapping table entry generates in the following several situations :(1)IGMP部分接收到成员关系报告时生成(*，G)表项；(1) The IGMP part generates (*, G) entry when receiving the membership report;(2)PIM SM部分接收到(*，G)JOIN报文时生成(*，G)表项；(2) PIM SM part generates (*, G) entry when receiving (*, G) JOIN message;(3)PIM SM部分接收到(S，G)JOIN报文时生成(S，G)表项；(3) PIM SM part generates (S, G) entry when receiving (S, G) JOIN message;(4)PIM SM部分接收到组播数据报文时生成(S，G)表项。(4) The PIM SM part generates (S, G) entry when receiving the multicast data message.4.如权利要求3所述的三层交换中IP组播精确端口转发的方法，其特征在于，所述步骤(2)中，组播路由端口映射表项的维护基于以下规则：4. the method for IP multicast accurate port forwarding in the three-layer exchange as claimed in claim 3, is characterized in that, in described step (2), the maintenance of multicast routing port mapping entry is based on the following rules:(1)IGMP部分删除成员时，对相应表项的相应出接口进行删除操作；(1) When IGMP partially deletes a member, delete the corresponding outgoing interface of the corresponding entry;(2)IGMP部分接收到成员关系报告时，对相应表项的相应出接口进行添加操作；(2) When the IGMP part receives the membership report, it adds an operation to the corresponding outgoing interface of the corresponding entry;(3)PIM-SM部分接收到PRUNE报文时，对相应表项的相应出接口进行删除操作；(3) When the PIM-SM part receives the PRUNE message, it deletes the corresponding outgoing interface of the corresponding entry;(4)PIM-SM部分接收到JOIN报文时，对相应表项的相应出接口进行添加操作；(4) When the PIM-SM part receives the JOIN message, it adds an operation to the corresponding outbound interface of the corresponding entry;(5)组播路由端口映射表表项的入接口根据数据报文的入口进行更新；(5) The incoming interface of the multicast routing port mapping table entry is updated according to the entry of the data message;(6)VLAN下物理端口的变化也触发组播路由端口映射表项的更新。(6) The change of the physical port under the VLAN also triggers the update of the multicast routing port mapping entry.5.如权利要求4所述的三层交换中IP组播精确端口转发的方法，其特征在于，组播路由端口映射表表项中设置定时器，用于实现表项的老化。5. the method for IP multicast accurate port forwarding in the three-layer exchange as claimed in claim 4, is characterized in that, timer is set in the multicast routing port mapping table item, is used for realizing the aging of table item.

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