tcp ipv6 max-mss

Function

The tcp ipv6 max-mss command sets the maximum MSS value for a TCP6 connection.

The undo ipv6 tcp ipv6 max-mss command deletes the maximum MSS value of a TCP6 connection.

By default, the maximum MSS value is not configured for TCP6 connections.

Format

tcp ipv6 max-mss max-mss-val

undo tcp ipv6 max-mss [ max-mss-val ]

Parameters

Parameter	Description	Value
max-mss-val	Specifies the maximum MSS value for a TCP6 connection.	The value is an integer ranging from 32 to 9600, in bytes.

Parameter

Description

Value

max-mss-val

Specifies the maximum MSS value for a TCP6 connection.

The value is an integer ranging from 32 to 9600, in bytes.

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ip-stack	write

Usage Guidelines

Usage Scenario

To establish a TCP6 connection, the MSS value is negotiated, which indicates the maximum length of packets that the local device can receive. If the path MTU is unavailable on one end of a TCP6 connection, this end cannot adjust the TCP6 packet size based on the MTU. As a result, this end may send TCP6 packets that are longer than the MTUs on intermediate devices, which will discard these packets. To prevent this problem, run the tcp ipv6 max-mss command on either end of a TCP6 connection to set the maximum MSS value of TCP6 packets. Then the MSS value negotiated by both ends will not exceed this maximum MSS value, and accordingly TCP6 packets sent from both ends will not be longer than this maximum MSS value and can travel through the intermediate network.

Example

# Set the maximum MSS value for a TCP6 connection to 1024 bytes.

<HUAWEI> system-view
[~HUAWEI] tcp ipv6 max-mss 1024