Embedded TCP/IP stack  4.7.0

◆ FNET_CFG_SOCKET_TCP_MSS

#define FNET_CFG_SOCKET_TCP_MSS   (0u)

The default value of the TCP_MSS option (TCP Maximum Segment Size). The TCP Maximum Segment Size (MSS) defines the maximum amount of data that a host is willing to accept in a single TCP segment.
This Maximum Segment Size (MSS) announcement is sent from the data receiver to the data sender and says "I can accept TCP segments up to size X". The size (X) may be larger or smaller than the default.
The MSS counts only data octets in the segment, it does not count the TCP header or the IP header.
This option can be set to:

  • 0 = This is the default value. The selection of the MSS is automatic and is based on the MTU of the outgoing interface minus 40 (does not include the 20 byte IP header and the 20 byte TCP header).
    It is done to assist in avoiding of IP fragmentation at the endpoints of the TCP connection.
  • Non-zero value (up to 64K) = The TCP segment could be as large as 64K (the maximum IP datagram size), but it could be fragmented at the IP layer in order to be transmitted across the network to the receiving host.

Definition at line 541 of file fnet_stack_config.h.


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