Transport Layer - Freie Universität Berlin

Causes/costs of congestion: Scenario 2
● Always: l in=l out (goodput)
● “perfect” retransmission only when loss: l’ in = l out
● Retransmission of delayed (not lost) packet makes l’ in larger (than perfect
case) for same l out
l out
R/2
l in
● “Costs” of congestion:
● More work (retrans) for given “goodput”
R/2
l out
● Unneeded retransmissions: link carries multiple copies of packet
Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 8: Transport Layer
R/2
R/3
l in
R/2
l out
R/2
R/4
l in
R/2
8.88