Thomas Kunz
Systems and Computer Engineering
24
Snoop: Description of Protocol
ndesign
does not cache packets from MH to FH
–bulk
of packet losses will be between MH and base
–but snooping on packets generates requests for
retransmissions at base much
faster than from remote FH
–enhance
TCP implementation at MH with “selective ACK” option:
nbase
keeps track of packets lost in a transmission window
nsends
bit vector back to MH to trigger retransmission of lost packets
nmobility
handling:
–when
handoff is requested by MH or anticipated by base station, nearby base stations begin receiving packets destined
for MH, priming their
cache
–caches
synchronized during actual handoff (since nearby bases cannot snoop on ACKs)