TCP Extended Fast Recovery and Segment Timing

摘要

When in Fast Recovery, Extended Fast Recovery operation starts a timer on the retransmission of each packet. The time expires in one adjusted round trip time. If there has not been an acknowledgement for the retransmitted packet and the Extended Fast Recovery timer expires, it is assumed that the retransmitted packet was lost and must be retransmitted again. Extended Fast Recovery operation keeps retransmitting the packet, once every adjusted round trip time, until an acknowledgement is received or the slow recovery timer expires. Segment Timing is an addition to Extended Fast Recovery where every sent packet is timed separately from the time of first transmission, not just retransmitted packets.

主权项

1. A transmission control protocol (TCP) transmitter comprising:
a port for receiving and transmitting TCP packets; a timer configured to time an adjusted round trip time for a transmitted packet; and retransmit logic coupled to said timer and said port for providing a packet for retransmission if said timer expires before an ACK is received for the packet.