Command Reference Guide

SROS Command Line Interface Reference Guide Global Configuration Mode Command Set

interface tunnel <id>

Use the interface tunnel command to create a virtual tunnel interface and enters the Tunnel Configuration

command set. See Tunnel Configuration Command Set on page 778 for details. Use the no form of this

command to delete a configured virtual tunnel interface.

Syntax Description

<id> Specifies the numerical tunnel interface identifying label (valid range: 1 to 1024).

Default Values

By default, there are no configured tunnel interfaces.

Command Modes

(config)# Global Configuration Mode

Functional Notes

A tunnel may become operational only under the following conditions:

1. The tunnel must have an IP address defined.

2. A valid source address or interface must be configured.

3. A valid destination address must be configured.

4. The physical interface used as the source for the tunnel must be operational.

5. The tunnel can not be in a recursive routing loop.

6. If keepalives are enabled, keepalive processing must be successful. See

keepalive <period> <retries>

on page 803 for details.

Technology Review

A tunnel interface enables standard point-to-point encapsulation between two links. Each endpoint must

have a unique tunnel configured. Tunneling allows an arbitrary payload protocol to be encapsulated within

a delivery protocol to provide point-to-point communications. The tunnel alone does not provide encryption

or any other means of high security. The tunnel interface is not a physical interface, so traffic will be routed

to the tunnel by the routing engine for encapsulation or decapsulation and typically forwarded out a

physical interface. A common tunnel implementation is the use of a GRE tunnel to transport IP multicast

traffic, such as that used by routing protocols across a link that only has IP unicast connectivity (such as

IPSec).