Configuring a Virtual Template Interface

Context

When PPP is required to bear other link layer protocols, VT interfaces are created to realize the intercommunication. The VT interface is used in VPN applications.

The link layer of VT interfaces only supports the PPP protocol and the network layer only supports IP.

The newly configured or modified parameters of a VT interface can take effect only after the shutdown and the undo shutdown command are run.
To configure or modify services such as MTU or IS-IS, configure or modify those services, and then perform related VT interface configuration on the other interfaces.

Procedure

Access the system view.
```
system-view
```
Create a VT interface and access the VT interface view.
```
interface virtual-template  vt-number
```
vt-number specifies the virtual template number. The value ranges from 0 to 1023.

Configure an IP address.

ip address ip-address { mask | mask-length } [ sub ]

Set the maximum number of links that support the sending of multicast or broadcast packets.
```
broadcast-limit link number
```
When a VT interface has many links, multicast or broadcast packets are sent through each link, affecting system performance. In this case, you can run the broadcast-limit link command to allow a specified number of links to send multicast or broadcast packets. If every link works at the highest speed, excess multicast or broadcast packets will be discarded.

For one VT interface, configure only one type of service, if possible.

By default, up to 30 links on a VT interface can send multicast or broadcast packets.

Follow-up Procedure

After VT interfaces are configured, you need to check whether the configuration is correct. In addition, you can view the statistics about VT interfaces.

Run the display interface virtual-template [ vt-number ] command to check the status of a VT interface.

Example

Run the display interface virtual-template command. If the configuration of a VT interface is displayed, it means the configuration succeeds.

<sysname> display interface virtual-template 1
Virtual-Template1 current state : UP
Line protocol current state :UP (spoofing)
Description: Virtual-Template1 Interface
Route Port,The Maximum Transmit Unit is 1492
Internet Address is 10.1.1.1/24
Physical is None, baudrate is 64000 bps
    Last 300 seconds input rate 0 bits/sec, 0 packets/sec
    Last 300 seconds output rate 0 bits/sec, 0 packets/sec
    Realtime 2 seconds input rate 0 bits/sec, 0 packets/sec
    Realtime 2 seconds output rate 0 bits/sec, 0 packets/sec
    Input: 0 packets,0 bytes,
           0 unicast,0 broadcast,0 multicast
           0 errors,0 drops,
    Output:0 packets,0 bytes,
           0 unicast,0 broadcast,0 multicast
           0 errors,0 drops
    Input bandwidth utilization  : --
    Output bandwidth utilization : --