tcp mss

Use tcp mss to set the TCP maximum segment size (MSS).

Use undo tcp mss to restore the default.

Syntax

tcp mss value

undo tcp mss

Default

The TCP MSS is not set.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

value: Specifies the TCP MSS in bytes. The minimum value is 128 bytes. The maximum value equals the maximum MTU that the interface supports minus 40.

Usage guidelines

The MSS option informs the receiver of the largest segment that the sender can accept. Each end announces its MSS during TCP connection establishment. If the size of a TCP segment is smaller than the MSS of the receiver, TCP sends the TCP segment without fragmentation. If not, TCP fragments the segment according to the receiver's MSS.

If you set the TCP MSS on an interface, the size of each TCP segment received or sent on the interface cannot exceed the MSS value.

This configuration takes effect only on TCP connections that are established after the configuration and not on the TCP connections that already exist.

This configuration is effective only on IP packets. If MPLS is enabled on the interface, do not set the TCP MSS on the interface.

Examples

# Set the TCP MSS to 300 bytes on VLAN-interface 100.

<Sysname> system-view
[Sysname] interface vlan-interface 100
[Sysname-Vlan-interface100] tcp mss 300