 traffic for F should take the indirect route. Figure 54.13 Routeing example A move in the direction of dynamic routeing is domain addressing, in which end point device addresses contain some routeing infor- mation. In a network of four switches, each switch can be regarded SO the routeing table for switch 2 in this example (Table 54.1), has as a separate domain, from one to four. Addresses of end point six entries, each showing the address of the end point device (see devices linked to each might have a digit referring to their immedi- also Figure 54.11) and the immediate link down which packets ate domain, followed by digits identifying them individually within intended for each device should be routed. that domain, such as 101 (number one device linked to packet A routeing table for switch 3 (Table 54.2) reveals a different switch 1,) or 304 (number three device linked to switch 4). picture because it looks at the end point devices from a different Routeing tables in domain addressing are kept to a minimum; not perspective within the network. every end point device need be recorded as many may share the Packets for more than one end point device can be routed down same link to a domain. The switch needs to know only where the the same link. For switch 2 this is true for end point devices A, B domains are to be found, rather than every device within those and E, F, in which case, there will be at least one more switch en domains. Instead of updating every routeing table on attaching a route to those destination devices. new device, only the table of the switch to which the device is A prerequisite of fixed routeing is the construction of routeing directly linked needs to be altered. tables which are then loaded into the network switches, usually Also, table search time is reduced when a call request packet when the network is first configured. Adding a new end point device arrives and a virtual call path needs to be set up. Alternatively, in a 54/14 Packet switching datagram network, as each datagram packet has