3Com 4007, Implementation Manual, Page: 367 / 684

Key Concepts
367
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Gateway — The IP address of the router interface through which the
packet travels on its next hop.
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Status — Information that the routing protocol has about the route,
such as how the route was put into the routing table.
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Time-to-live (TTL) — Time-to-live measured in seconds before this
learned route will time out.
Figure 38 shows the routing table contents of the router in Figure 37.
Figure 38 Sample Routing Table
Routing table data is updated statically or dynamically:
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Statically — You manually enter static routes in the routing table.
Static routes are useful in environments where no routing protocol is
used or where you want to override some of the routes that are
generated with a routing protocol. Because static routes do not
automatically change in response to network topology changes,
manually configure only a small number of reasonably stable routes.
Static routes do not time out, but they can be learned.
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Dynamically — Routers use a protocol such as RIP or OSPF to
automatically exchange routing data and to configure their routing
tables dynamically. Routes are recalculated at regular intervals. This
process helps you to keep up with network changes and allows the
module to reconfigure routes quickly and reliably. Interior Gateway
Protocols (IGPs), which operate within networks, provide this
automated method.
Routing table
default route
158.101.1.0
158.101.2.0
158.101.3.0
Destination Subnet mask
255.255.255.0
255.255.255.0
255.255.255.0
255.255.255.0
Metric
2
2
2
2
Gateway
160.1.1.254
160.1.1.254
160.1.1.254
160.1.1.254
Status
learned - RIP
learned - OSPF - INTRA
learned - OSPF - INTRA
learned - OSPF - INTRA
TTL
170
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