Selective repeat

data from above :

• if next available seq # in window, send pkt

timeout(n):

• resend pkt n, restart timer

ACK(n) in [sendbase,sendbase+N]:

• mark pkt n as received

• if n smallest unACKed pkt, advance window base to next unACKed seq #

pkt n in [rcvbase, rcvbase+N-1]

• send ACK(n)

• out-of-order: buffer

• in-order: deliver (also deliver buffered, in-order pkts), advance window to next not-yet-received pkt

pkt n in [rcvbase-N,rcvbase-1]

• ACK(n)

otherwise:

• ignore

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