3com 530 Manuel D’Utilisation

 

 

A routing environment allows stations to communicate 

 

indirectly. Following the example in 

 

 

 

assume that a station on LAN 1 wants to communicate 

 

with a network server on LAN 2. The station on LAN 1, 

 

constructs a 

 

 datalink header (see 

 

 

 

with the source station’s hardware address, and also 

 

the destination hardware address of the local router. To 

 

direct the packet to its final network destination, the 

 

source station must complete the 

 

 network 

 

header with the destination network address of LAN 2.

 

Once the packet is received by the Router A, 

 

attached to LAN 1, it strips off the network header 

 

(refer to 

 

 

) and examines the Layer 3 

 

datalink header information. It then reviews its 

 

routing tables in order to establish where to forward 

 

the data packet. It is possible that the LAN 1 router 

 

has multiple outgoing ports that would allow 

 

different transmission routes to the destination 

 

network. In our example using 

 

 

, a packet 

 

could go via Router D to get to Router B, or it could 

 

go more directly across a single direct link between 

 

Router A and Router B.

 

 

Data Packet Containing Hardware And Software Addresses

 

 

The local router contains, within its routing table, 

 

information which will allow it to determine the best 

 

data transmission route. The type of information the 

 

router uses to make these assessments is protocol 

 

dependent, and some communications protocols 

 

may employ a range of routing algorithms, and 

 

accompanying routing protocols. In the case of the 

 

TCP/IP protocol suite, the OfficeConnect Remote 

 

utilizes the Routing Information Protocol (RIP). RIP is 

 

also known as a 

 

 protocol. 

Rc.bk : RCAPPA.FRM  Page 9  Thursday, July 10, 1997  9:53 AM