CN1988497B - Method for Processing Layer 2 Data Packet in Ethernet Switch - Google Patents

Abstract

A method for processing layer 2 data packets in an Ethernet switch, setting the port for special services in the switch as a CUSTOM port of QINQ, and setting the PVID as a special value not bound to any other port. The special service here refers to the VPLS and VPWS mentioned above or other layer-2 advanced function services. Compared with the prior art, the present invention realizes some special functions in the distributed switch, and effectively restrains the behavior of VLAN broadcasting where the MAC address cannot be found.

Description

Method for Processing Layer 2 Data Packet in Ethernet Switch

technical field

The invention relates to an Ethernet switch in the field of communication, in particular to a method for suppressing the processing of layer-2 data packets in a distributed switch.

Background technique

In a switch, when processing a layer-2 data packet, it first uses the destination MAC to look up the MAC table. If there is such a MAC address in the MAC table, the data packet is forwarded out from the outgoing port in the MAC table. If there is no such address in the MAC table, the data packet will be broadcast and forwarded in the VLAN carried by the data packet or in the default PVLAN.

The characteristic of the switch is that the above forwarding process is generally completed by an integrated ASIC chip, that is to say, the above forwarding process is automatically completed by the hardware, which is cheap, but not easy to expand, and difficult to implement some such as VPLS (VPLS: Virtual Private Advanced functions of LAN Service, virtual private local area network service), VPWS (VPWS: Virtual Private Wire Service virtual private line service).

Now in order to implement some special Layer 2 functions not supported by ordinary ASIC chips in the switch, such as VPLS and VPWS, the data packets must be sent to the designated special board for special processing. However, when a port receives a Layer 2 data packet whose MAC address cannot be found, it will broadcast in the VLAN. Once broadcast, it will go against the original intention of implementing VPLS/VPWS.

Contents of the invention

The technical problem to be solved by the invention is to propose a method for processing the two-layer data packet and suppressing the broadcast of the data packet.

The technical solution of the present invention is to set the port for special service in the switch as the CUSTOM port of QINQ, and set the PVID to a special value not bound with any other port. The special service here refers to the VPLS and VPWS mentioned above or other layer-2 advanced function services.

You can first set the port for special business as ACCESS port, and then set the port for special business as CUSTOM port of QINQ.

When the data packet enters the forwarding chip through the special port of the switch, use PVID+MAC address to search the MAC table, if not found, broadcast in the special VLAN, if the special service board receives this packet, use the network processor to process the data The packet is processed arbitrarily, and the data is sent out after processing.

Compared with the prior art, the present invention realizes some special functions in the distributed switch, and effectively restrains the behavior of VLAN broadcasting where the MAC address cannot be found.

Detailed ways

First introduce the QINQ function. The QINQ function is the tag stacking function, which is to add a layer of VLAN TAG (label) to the original data packet entering the switch and send it out of the switch. QINQ is divided into CUSTOM port and UPLINK port.

The CUSTOM port needs to set PVID (PVID: Port Vlan ID, also known as port default VLAN ID, that is, port default Vlan ID). This PVID is the VLAN TAG to be added to the original data packet. When a data packet enters the CUSTOM port, if the original data packet does not have a VLAN TAG, the data packet will add a layer of PVID VLAN TAG and go out from the UPLINK port. If the original data packet has a layer of VLAN TAG, the data packet will add another layer The VLAN TAG of PVID goes out from the UPLINK port, so the original VLAN TAG is the inner label, and the newly added VLAN TAG is the outer label.

When the data packet enters the UPLINK port, if the original data packet has two layers of VLAN TAG, the outer VLAN TAG is stripped off, and the data packet with the inner VLAN TAG goes out from the CUSTOM port. If the original data packet has a layer of VLAN TAG, then strip the VLAN TAG out from the CUSTOM port.

The method of the present invention is exactly, in switch, the port that does special business is set to the CUSTOM port of QINQ, and PVID is set to a special value, does not have any other port to belong to this VLAN.

You can first set the port with a special function as an ACCESS port (ACCESS port: the port can only belong to one VLAN and is untagged), and the PVID is set as a special reserved value. Then set the port to QINQ's CUSTOM port.

After the above configuration is done, all Layer 2 data packets entering the port will not be broadcast in the ingress VLAN, but on the basis of the original packet, a layer of PVID VLAN TAG will be added and broadcast in the PVID, because this PVID does not follow the Any other port is bound, so this data packet is not forwarded from any port, but broadcast to the special function processing board.

When the data packet enters the forwarding chip through the special port of the switch, the PVID+MAC address is used to search the MAC table, but if it cannot be found, it broadcasts in the special VLAN, and only the special service board may receive the packet. The special service board can use the network processor to process the data packets arbitrarily, and then send the data out after processing. However, it should be noted that the data packets entering the special service board are no longer original data packets, but a data packet with a layer of VLAN TAG added. You can ignore the outer VLAN during processing, and strip the outer VLAN TAG after processing. Lose.

Claims (2)

1. method of in Ethernet switch, handling the Layer 2 data bag, the port of doing particular service in the switch is arranged to the CUSTOM port of QINQ, PVID is set as not a particular value with any other port binding, wherein, described particular service comprises virtual special local area network service VPLS or virtual dedicated line service VPWS.

2. the method for in Ethernet switch, handling the Layer 2 data bag according to claim 1, it is characterized in that, when the port of packet by switch enters forwarding chip, show with PVID+MAC address search MAC, if can not find out, in VLAN, to broadcast, business board is if receive this bag, then utilize network processing unit to come packet is done any processing, handle that again data are sent.