The tcp max-mss command configures the maximum Maximum Segment Size (MSS) value for a TCP connection.
The undo tcp max-mss command deletes the maximum MSS value of a TCP connection.
By default, the maximum MSS value is not configured for TCP connections.
| Parameter | Description | Value |
|---|---|---|
| mss-value | Specifies the maximum MSS value for a TCP connection. | The value is an integer ranging from 32 to 9600, in bytes. |
Usage Scenario
To establish a TCP connection, the MSS value is negotiated, which indicates the maximum length of packets that the local device can receive. This length is the TCP payload length, excluding that of the TCP header. If the path MTU is unavailable on one end of a TCP connection, this end cannot adjust the TCP packet size based on the MTU. As a result, this end may send TCP packets that are longer than the MTUs on intermediate devices, which will discard these packets. To prevent this problem, run the tcp max-mss command on either end of a TCP connection to set the maximum MSS value of TCP packets. Then the MSS value negotiated by both ends will not exceed this maximum MSS value, and accordingly TCP packets sent from both ends will not be longer than this maximum MSS value and can travel through the intermediate network.
Precautions
The maximum MSS value configured using the tcp max-mss command must be greater than the minimum MSS value configured using the tcp min-mss command.