Configuring a Layer-2 Eth-Trunk Interface

The Layer-2 attributes of an Eth-Trunk interface define the link layer attributes of the interface.

Context

To add an Eth-Trunk interface to a VLAN, configure Layer-2 functions for the Eth-Trunk interface.

Layer-2 Eth-Trunk interfaces are mainly used in trunk interfaces in VLANs to increase the bandwidth for communication between the VLANs of two devices.

Procedure

Access the system view.
```
system-view
```
Create an Eth-Trunk interface and access the Eth-Trunk interface view.
```
interface eth-trunk trunk-id
```
Switch the Eth-Trunk interface from the Layer-3 mode to the Layer-2 mode.
```
portswitch
```
By default, the Eth-Trunk interface works in Layer-3 mode.

After the Eth-Trunk is switched to the Layer-2 mode, the Layer-3 tag and functions of the Eth-Trunk interface are displayed, and the Eth-Trunk interface uses a MAC address.

To add an Eth-Trunk interface to a VLAN, switch the Eth-Trunk interface from the Layer-3 mode to the Layer-2 mode. During the switching, only the shutdown, undo shutdown, and description commands can be run on the interface. If other command configurations exist on the interface, delete them.

The undo portswitch command switches an Eth-Trunk interface from the Layer-2 mode to the Layer-3 mode.
- The minimum interval for running the portswitch and undo portswitch commands in consecutive order is 30s.
- Changing the working mode of an Eth-Trunk interface has no impact on interface addition to the Eth-Trunk interface. Interfaces can be added to either a Layer-2 or Layer-3 Eth-Trunk interface.
Optional: Enable the bypass detection function on the interface.
detect-mode tap

After bypass detection is enabled, the device detects packets received on this interface and then discards them.
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.
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.

Follow-up Procedure

After configuring a Layer-2 Eth-Trunk interface, view the brief information about the interface, including the physical state, protocol state, and bandwidth utilization.

Run the display interface eth-trunk [ trunk-id ] command to check the status of the Eth-Trunk interface.
Run the display interface brief command to check the brief information of the Eth-Trunk interface, including physical state, protocol state, and bandwidth utilization.

Example

Run the display interface eth-trunk command. The command output shows the Hash algorithm of an Eth-Trunk interface.

Eth-Trunk1 current state : UP
Line protocol current state : UP
Description : Eth-Trunk1 Interface
Route Port,Hash arithmatic : According to flow,Maximal BW: 2G, Current BW: 2G,
The Maximum Transmit Unit is 1500
Internet protocol processing : disabled 
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 00e0-fc09-9722
Physical is ETH_TRUNK
    Last 300 seconds input rate 0 bytes/sec, 0 packets/sec
    Last 300 seconds output rate 0 bytes/sec, 0 packets/sec
    Realtime 0 seconds input rate 0 bits/sec, 0 packets/sec  
    Realtime 0 seconds output rate 0 bits/sec, 0 packets/sec  
    Input:     1 packets,3 bytes,
               7 unicast,9 broadcast,8 multicasts
               10 errors,5 drops,11 unknowprotocol
    Output:    2 packets,4 bytes,
               12 unicast,14 broadcast,13x multicasts
               15 errors,6 drops
    Input bandwidth utilization  : 0.00%
    Output bandwidth utilization : 0.00% 
-----------------------------------------------------
PortName                Status              Weight
-----------------------------------------------------
GigabitEthernet 0/0/1       UP                  1
GigabitEthernet 0/0/2       UP                  1
-----------------------------------------------------
The Number of Ports in Trunk : 2
The Number of UP Ports in Trunk : 2

Run the display interface brief command. The command output shows the physical state, link-layer protocol status, bandwidth utilization of an Eth-Trunk interface and the number of error packets.

<sysname> display interface brief | begin Eth-Trunk
PHY: Physical 
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
(b): BFD down
(d): Dampening Suppressed
InUti/OutUti: input utility/output utility 
Interface                   PHY      Protocol InUti OutUti  inErrors outErrors 
Eth-Trunk1                  up       up          0%     0%         0         0 
  GigabitEthernet 0/0/1      up       up          0%     0%         0         0 
  GigabitEthernet 0/0/2      up       up          0%     0%         0         0
Eth-Trunk1.1                up       up          0%     0%         0         0