peer tcp-mss (BGP-VPN instance IPv4 address family view)

Function

The peer tcp-mss command configures a TCP MSS value used when the local device establishes TCP connections with a peer.

The undo peer tcp-mss command deletes the configured TCP MSS value.

By default, no TCP MSS is configured for the local device to establish TCP connections with a peer.

Format

peer ipv4-address tcp-mss tcp-mss-number

undo peer ipv4-address tcp-mss

Parameters

Parameter	Description	Value
ipv4-address	Specifies the IPv4 address of a peer.	The value is in dotted decimal notation.
tcp-mss-number	Specifies the TCP MSS value used for TCP connection establishment.	The value is an integer ranging from 176 to 4096, in bytes.

Parameter

Description

Value

ipv4-address

Specifies the IPv4 address of a peer.

The value is in dotted decimal notation.

tcp-mss-number

Specifies the TCP MSS value used for TCP connection establishment.

The value is an integer ranging from 176 to 4096, in bytes.

Views

BGP-VPN instance IPv4 address family view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bgp	write

Usage Guidelines

Usage Scenario

You can run the peer tcp-mss command to configure a TCP MSS value used for TCP connection establishment so that it is used to encapsulate BGP packets when the path MTU is unavailable. Such configuration improves network performance.

Precautions

If you change the tcp-mss-number value, the TCP connection will be re-established.

If both the peer tcp-mss and peer path-mtu auto-discovery commands are run, note the following rules:

If the local device obtains the path MTU, the smaller value of TCP MSS and path MTU takes effect.
If the local device fails to obtain the path MTU, TCP MSS takes effect.

Example

# Configure a TCP MSS value for the local device to establish TCP connections with the peer.

<HUAWEI> system-view
[~HUAWEI] ip vpn-instance vpna
[*HUAWEI-vpn-instance-vpna] ipv4-family
[*HUAWEI-vpn-instance-vpna-af-ipv4] route-distinguisher 100:1
[*HUAWEI-vpn-instance-vpna-af-ipv4] vpn-target 111:1 both
[*HUAWEI-vpn-instance-vpna-af-ipv4] quit
[*HUAWEI-instance-vpna] quit
[*HUAWEI] bgp 100
[*HUAWEI-bgp] ipv4-family vpn-instance vrf1
[*HUAWEI-bgp-vrf1] peer 10.1.1.1 as-number 100
[*HUAWEI-bgp-vrf1] peer 10.1.1.1 tcp-mss 200