Cabletron Systems SmartSwitch 8-slot, Руководство пользователя

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Chapter 6: Routing Policy Configuration Guide
6 - 4 SSR User Reference Manual
Route-Filter
This component specifies the individual routes which are to be imported or restricted.
The preference to be associated with these routes can also be explicitly specified using
this component.
The preference associated with the imported routes are inherited unless explicitly
specified. If there is no preference specified with a route-filter, then the preference is
inherited from the one specified with the import-source.
Every protocol (RIP, OSPF, and BGP) has a configurable parameter that specifies
default-preference associated with routes imported to that protocol. If a preference is
not explicitly specified with the route-filter, as well as the import-source, then it is
inherited from the default-preference associated with the protocol for which the routes
are being imported.
Export Policies
Export policies control the redistribution of routes to other systems. They determine
which routes are advertised by the Unicast Routing Process to other systems. Every
export policy can have up to three components:
• Export-Destination
• Export-Source
• Route-Filter
Export-Destination
This component specifies the destination where the routes are to be exported. It also
specifies the attributes associated with the exported routes. The interface, gateway or
the autonomous system to which the routes are to be redistributed are a few examples
of export-destinations. The metric, type, tag, and AS-Path are a few examples of
attributes associated with the exported routes.
Export-Source
This component specifies the source of the exported routes. It can also specify the
metric to be associated with the routes exported from this source.
The routes to be exported can be identified by their associated attributes:
• Their protocol type (RIP, OSPF, BGP, Static, Direct, Aggregate).
• Interface or the gateway from which the route was received.
• Autonomous system from which the route was learned.
• AS path associated with a route. When BGP is configured, all routes are assigned an
AS path when they are added to the routing table. For interior routes, this AS path