The Maximum Transfer Unit (MTU) is the maximum packet size which may be sent on the network. The packet size includes the IP header, protocol header and any data in the packet. The MTU value is set in the device table for each interface.

The Maximum Segment Size (MSS) is the maximum amount of data which may be sent in a TCP packet. The MSS values are sent in the initial SYNC message, where each side declares the maximum amount of data it can receive in a packet. The MSS value does not include any of the protocol headers. The MSS value sent in SYNC message is calculated from the MTU value specified in the device table

The most important data structure of RTIP-32 is the Data Control Unit (DCU, data buffer). DCUs contain link management fields and a pointer to a data area. The primary job of RTIP-32 is to route DCUs from the device driver's receive routine to the application layer doing network receives and from the application layer to the device driver's send routine on sends. DCUs are routed between layers via internal queues. The TCP protocol layer relies on an internal sliding window buffering scheme.

Left TCP/IP Networking

Blocking and Non-Blocking Sockets

Down Fragmentation