TCP MSS and window size
MSS is found in the options fields of the TCP header in the SYN packet and is defined during the 3-way handshake. It cannot be changed during a session. It has a maximum value of 65535 (2 byte field).
The default TCP Maximum Segment Size is for IPv4 is 536. For IPv6 it is 1220 but it can be changed as mentioned above.
The MSS can be adjusted at the beginning of a session using the TCP MSS feature on Cisco devices.
Window size has a maximum value of 65535 (2 byte field) and is found in the main TCP header. It can be renegotiated during a session.
Links to this page:
- ASA - VTI VPN and MSS
- MTU - Adjusting MTU to accommodate additional headers
- MTU - Benefits of large L2 MTU
- MTU - MSS and Jumbo Frames
- TCP - Congestion control
- TCP - Determining the MSS
- TCP - SEQ and ACK values
- TCP - Slow start
- TCP - Three-way handshake
- TCP - Window Size Scaling
- TCP - factors affecting segment size
- UDP - Maximum Datagram Size