Intel ER8100STUS - Express 8100 Router, Справочное руководство

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Reference.bok : Chapter09 90 Wed Apr 22 10:58:08 1998
90
Static Routes and Services
Novell IPX Routing
Example description
The above example is configured as follows:
■
The primary link from network 1 to network 2 is the main route between net-
work 1 and 2. This link uses dynamic routing (RIP and SAP).
■
The secondary link between router 1 and router 3 is used as a static backup
route between network 1 and 2 which is only used if the primary route fails.
To allow general access between networks 1 and 2 in case the primary link
should fail:
-
a static backup route to network 1 is configured in router 3
- a static backup route to network 2 is configured in router 1
■
To allow the PC to access the server on network 1, an additional static
backup route to the internal network number of the server and a static service
to the server must be established in router 3.
Novell IPX servers use an internal network number which must be used
when routing information to the server.
■
For correct operation, the metrics for the backup routes must be higher than
those for the primary route. To establish the static backup routes (in routers 1
and 3), dynamic routing over the backup link must be disabled and the static
backup routes should be configured to
Use best route
. These routes are
then only used if the primary route fails.
Dynamic routes with
static backup routes
consideration
For correct operation, a static backup route must have a higher metric than the
primary route. If the primary route is a dynamic route using RIP, the metrics for
the route are calculated automatically by the router. If the speed of the primary
and backup links are similar, in certain circumstances the router can calculate the
metrics for the primary route to be higher than the those for static backup link. If
this occurs, the router forwards data via the static backup link rather than the dy-
namic link. To avoid this, the metrics for the static backup link should be set
higher than the calculated value (for example, by about 50%).
Establishing static
routes and static
services
The easiest way to establish static routes, static backup routes and static services
is to replace dynamic routes and services. This ensures that the static route/ser-
vice information is correct (especially important for static services which can be
quite complex), and that the metrics for the route/service are automatically cal-
culated.
1
Configure the router to use dynamic routing (using RIP/SAP) over the link.
This is done by setting the
Routing Protocol
parameter to
RIP/SAP
.
2 Obtain the relevant information for the static routes and services from the
routing table for the router.
For static routes (and static backup routes), the information required
includes the network numbers and the associated metrics (delays and
hops). For static services, the information required includes, the server
names, types, network, node, socket and the hops to the server.