Command Reference Guide

SROS Command Line Interface Reference Guide Ethernet Interface Configuration Command Set

mtu <size>

Use the mtu command to configure the maximum transmit unit (MTU) size for the active interface. Use

the no form of this command to return to the default value.

Syntax Description

<size> Configures the window size for transmitted packets. The valid ranges for the

various interfaces are listed below:

Ethernet (eth 0/1) 64 to 1500

virtual Frame Relay sub-interfaces (fr 1.16) 64 to 1520

virtual PPP interfaces (ppp 1) 64 to 1500

loopback interfaces 64 to 1500

Default Values

<size> The default values for the various interfaces are listed below:

Ethernet (eth 0/1) 1500

virtual Frame Relay sub-interfaces (fr 1.16) 1500

virtual PPP interfaces (ppp 1) 1500

loopback interfaces 1500

Command Modes

(config-interface)# Interface Configuration Mode required (applies only to IP interfaces)

Valid interfaces include: Ethernet, virtual Frame Relay sub-interfaces (fr 1.16),

virtual PPP interfaces (ppp 1), and loopback interfaces.

Functional Notes

OSPF will not become adjacent on links where the MTU sizes do not match. If router A and router B are

exchanging hello packets but their MTU sizes do not match, they will never reach adjacency. This is by

design and required by the RFC.

Usage Examples

The following example specifies an MTU of 1200 on the Ethernet interface:

(config)#interface eth 0/1

(config-eth 0/1)#mtu 1200