3Com 4007, Руководство по внедрению, Страница: 522 / 684

522 C
HAPTER
20: IPX R
OUTING
The routing table consists of the following elements:
■
Interface — The interface number of the router that is used to reach
a network segment
■
Address
— The network segments that the router knows about
■
Hops to network — The number of routers that must be crossed to
reach a network segment
■
Ticks to network — An estimate of the time that it takes to reach a
network segment. There are 18.21 ticks in a second.
■
Node — The node address of the router that can forward packets to
each network segment. When the node is set to all 0s, the router is
directly connected.
■
Age — The time since the network’s last update
Figure 61 shows an example of a typical routing information table.
Figure 61 Sample Routing Table
The routing information table is updated statically or dynamically.
Selecting the Best
Route
Large networks contain many possible routes to each destination. A
router performs the following steps to find the best route toward a
destination:
■
If one route requires the lowest number of ticks, the router selects it as
the best route.
■
If multiple routes require the same lowest number of ticks, the router
selects the route that requires the lowest number of hops as the
best route.
■
If multiple routes require the same lowest number of ticks and hops,
the router may select any of them as the best route.
Routing table
Interface Address Hops Ticks Node Age
1 1 1 1 00-00-00-00-00-00 0
2 45469f30 1 1 00-00-00-00-00-00 0
2 45469f33 2 3 08-00-17-04-33-45 40