Configuring Transparent Transmission of Protocol Packets in a VLAN

When the device used as the gateway or Layer 2 switches is enabled with snooping functions such as DHCP, IGMP, or MLD snooping, the device needs to parse and process protocol packets such as ARP, DHCP, and IGMP packets. That is, protocol packets received by an interface are sent to the CPU for processing. The interface sends protocol packets without differentiating VLANs. If the preceding functions are deployed, protocol packets from all VLANs are sent to the CPU for processing.

If the device is a gateway of some VLANs or snooping functions is deployed in some VLANs, the device does not need to process protocol packets in other VLANs. After the protocol packets in other VLANs are sent to the CPU, the CPU needs to forward them to other devices. This mechanism is called software forwarding. Software forwarding affects the forwarding speed and efficiency of protocol packets because protocol packets need to be processed.

To address this issue, deploy transparent transmission of protocol packets in VLANs where protocol packets do not need to be processed. This function enables the device to transparently transmit the protocol packets in the VLANs to other devices, which improves the forwarding speed and efficiency.

Procedure

• Configure transparent transmission of protocol packets in a VLAN.
  1. Run:

     system-view

     The system view is displayed.

  2. Run:

     vlan vlan-id

     A VLAN is created and the VLAN view is displayed. If the specified VLAN has been created, the VLAN view is directly displayed.

  3. Run:

     protocol-transparent

     Transparent transmission of protocol packets in VLANs is configured.

     By default, transparent transmission of protocol packets in a VLAN is disabled.

• Configure transparent transmission of protocol packets in multiple VLANs.
  1. Run:

     system-view

     The system view is displayed.

  2. Run:

     vlan batch { vlan-id1 [ to vlan-id2 ] } &<1-10>

     Create one or more VLANs.
  3. Run:

     vlan range { vlan-id1 [ to vlan-id2 ] } &<1-10>

     A temporary VLAN range is created and its view is displayed. If the VLAN range has been created, this command directly displays the VLAN-Range view.

     Uncreated VLANs cannot be added to a temporary VLAN range.

  4. Run:

     protocol-transparent

     Transparent transmission of protocol packets in VLANs is configured.

     By default, transparent transmission of protocol packets is disabled in VLANs of a temporary VLAN range.

• The vlan range command configuration is not saved in the configuration file. If services are configured in the VLAN-Range view, the service configurations of all the VLANs in the VLAN range will be saved in the configuration file.
• After transparent transmission of protocol packets is configured in a VLAN, the VLAN cannot be configured as the multicast VLAN or control VLAN.
• Before running this command, ensure that IGMP or MLD snooping has been disabled in the VLAN. Otherwise, the configuration may fail.