Telematics Chapter 6: Network Layer - Freie Universität Berlin

Routing
● Most important functionality on Layer 3 is addressing and routing.
● Each computer has to be assigned a worldwide unique address
● Every router manages a table (Routing Table) which indicates, which
outgoing connection has to be selected for a certain destination.
L4
L1
L2
L3
To destination By connection
A L2
B L1
C L3
D L2
● The routing tables can be determined statically; however it is better to
adapt them dynamically to the current network status.
● With connectionless communication, the routing must be done for
each packet separately. The routing decision can vary from packet to
packet.
● With virtual connections, routing is done only once (connection
establishment, see ATM), but the routing tables are more extensive
Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 6: Network Layer
6.11