Ip Routing Protocol Overview; Introduction To Ip Route And Routing Table - 3Com 8807 Configuration Manual

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Introduction to IP
Route and Routing
Table
IP Route and Route
Segment
IP R
OUTING
n
A router that is referred to in the following or its icon represents a generalized
router or an Switch 8800 Family series routing switch running routing protocols.
To improve readability, this will not be described in the other parts of the manual.
For the configuration of VPN instance, refer to the MPLS module in 3Com Switch
8800 Family Series Routing Switches Operation Manual.
Routers are implemented for route selection in the Internet. A router works in the
following way: The router selects an appropriate path (through a network)
according to the destination address of the packet it receives and forwards the
packet to the next router. The last router in the path is responsible for submitting
the packet to the destination host.
In Figure 69, R stands for a router. A packet sent from Host A to Host C should go
through two routers and the packet is transmitted through two hops. Therefore,
when a node (router) is connected to another node through a network, they are in
the same route segment and are deemed as adjacent in the Internet. That is, the
adjacent routers refer to two routers connected to the same network. The number
of route segments between a router and hosts in the same network counted as
zero. In Figure 69, the bold arrows represent these route segments. Which physical
links comprise which route segment is not a concern of a router however.
P
ROTOCOL
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VERVIEW