Configuring an Eth-Trunk Subinterface

Procedure

1. Access the system view.

   system-view

2. Create an Eth-Trunk interface and access the Eth-Trunk interface view.

   interface eth-trunk trunk-id

3. Return to the system view.

   quit

4. Create an Eth-Trunk subinterface and access the Eth-Trunk subinterface view.

   interface eth-trunk trunk-id.subnumber

   subnumber specifies the number of an Eth-Trunk subinterface. The number ranges from 1 to 4096 on the FW. A maximum of 1024 subinterfaces can be created on each Eth-Trunk interface.

5. Configure an IP address for the Eth-Trunk subinterface.

   • Configure an IPv4 address for the Eth-Trunk subinterface.

     To configure an IPv4 address for the Eth-Trunk subinterface, run the ip address ip-address { mask | mask-length } [ sub ] command.

   • Configure an IPv6 address for the Eth-Trunk subinterface.

     Configure an IPv6 address for the Eth-Trunk subinterface based on actual situations:

     • To configure an automatic link-local address for the subinterface, run the ipv6 address auto link-local command.
     • To configure a link-local address for the subinterface, run the ipv6 address ipv6-address link-local command.
     • To configure a global unicast address for the subinterface, run the ipv6 address { ipv6-address | prefix-length } command.
     • To configure an IPv6 address in the format of EUI-64 for the subinterface, run the ipv6 address ipv6-address/prefix-length [ eui-64 ] command.

6. Configure an encryption type and associated VLAN ID for the Eth-Trunk subinterface.

   vlan-type dot1q vlan-id

   

   The FW allows you to associate an Eth-Trunk subinterface with a maximum of one VLAN.

   By default, the subinterface has no encryption types or associated VLAN IDs.

   Ensure that the subinterfaces at both ends of a link have the same VLAN ID, which ensures VLAN connectivity.

7. Optional: Configure an MTU for the Eth-Trunk subinterface.

   • Configure an IPv4 MTU for the Eth-Trunk subinterface.

     To configure an IPv4 MTU for the subinterface, run the mtu mtu command.

     The MTU is expressed in bytes. The MTU range of an Eth-Trunk subinterface depends on devices. The default MTU is 1500.

     

     If you run the mtu command to set an MTU to be smaller than 1280 for an Eth-Trunk subinterface running IPv6, IPv6 cannot work properly on the subinterface. When IPv6 runs on an Eth-Trunk subinterface, set the MTU of the subinterface to be greater than or equal to 1280.

   • Configure an IPv6 MTU for the Eth-Trunk subinterface.

     1. To enable IPv6 for the subinterface, run the ipv6 enable command

     2. To configure an IPv6 MTU for the subinterface, run the ipv6 mtu mtu command.

        The MTU is expressed in bytes. The MTU range of an Eth-Trunk subinterface depends on devices. The default MTU is 1500.

        

        The Quality of Service (QoS) queue length is limited. If the MTU is too small but the size of a packet is large, the packet may be divided into many fragments and discarded by the QoS queue. To prevent this problem, increase the QoS queue length accordingly. FIFO is used by default on interfaces, which can change the QoS queue length.

8. Optional: Configure the automatic interface disabling function based on the session usage.
   • In the system view, run the firewall exceeded session enable command to configure the function that the interface is automatically disabled when the session usage reaches the threshold.
   • In the system view, run the firewall exceeded session shutdown interface command to configure the list of interfaces that need to be disabled when the session usage reaches the threshold.
   • In the system view, run the snmp-agent session trap threshold command to configure the session usage threshold that triggers the interface to be automatically disabled.

9. Optional: Configure the automatic interface disabling function based on the CPU usage.
   • In the system view, run the firewall exceeded cpu-usage enable command to configure the function that the interface is automatically disabled when the CPU usage reaches the threshold.
   • In the system view, run the firewall exceeded cpu-usage shutdown interface command to configure the list of interfaces that need to be disabled when the CPU usage reaches the threshold.
   • In the system view, run the firewall exceeded cpu-usage threshold command to configure the CPU usage threshold that triggers the interface to be automatically disabled.

10. Optional: Configure the sticky load balancing function.

    redirect-reverse next-hop ipv4-address [ per-packet ]
    ipv6 redirect-reverse next-hop ipv6-address [ per-packet ]

    After this command is configured, the FW directly uses the inbound interface as the outbound interface of the response packet when forwarding the response packet, instead of searching the routing table for an outbound interface.