Thomas Kunz
Systems and Computer Engineering
408
Snoop: Description of Protocol
nprocessing packets
from FH
–new packet in the normal TCP sequence:
ncache and forward to
MH
–packet out-of sequence and cached earlier:
nsequence number >
last ack from MH: packet probably lost, forward it again
notherwise, packet
already received at MH, so drop
–but: original ACK could have been lost, so fake ACK
again
–packet out-of sequence and not cached yet:
npacket either lost
earlier due to congestion or delivered out-of-order: cache packet and mark as retransmitted, forward to MH