Cabletron Systems GIGAswitch GSR-16, Руководство пользователя

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Chapter 11: Routing Policy Configuration Guide
158 DIGITAL GIGAswitch/Router User Reference Manual
Creating an Aggregate Route
Route aggregation is a method of generating a more general route, given the presence of a
specific route. The routing process does not perform any aggregation unless explicitly
requested. Aggregate-routes can be constructed from one or more of the following
building blocks:
• Aggregate-Destination - This component specifies the aggregate/summarized route. It
also specifies the attributes associated with the aggregate route. The preference to be
associated with an aggregate route can be specified using this component.
• Aggregate-Source - This component specifies the source of the routes contributing to
an aggregate/summarized route. It can also specify the preference to be associated
with the contributing routes from this source. The routes contributing to an aggregate
can be identified by their associated attributes, including protocol type, tag associated
with a route, and so on.
• Route Filter - This component provides the means to define a filter for the routes to be
aggregated or summarized. Routes that match a filter are considered as eligible for
aggregation. This can be done using one of two methods:
– Creating a route-filter and associating an identifier with it. A route-filter has
several network specifications associated with it. Every route is checked against
the set of network specifications associated with all route-filters to determine its
eligibility for aggregation. The identifier associated with a route-filter is used in the
ip-router policy aggr-gen command.
– Specifying the networks as needed in the ip-router policy aggr-gen command.
• If you want to create a complex route-filter, and you intend to use that route-filter in
several aggregates, then the first method is recommended. It you do not have complex
filter requirements, then use the second method.
After you create one or more building blocks, they are tied together by the ip-router
policy aggr-gen command.
To create aggregates, enter the following command in Configure mode:
The <aggr-dest-id> is the identifier of the aggregate-destination that specifies the
aggregate/summarized route.
The <aggr-src-id> is the identifier of the aggregate-source that contributes to an aggregate
route. If an aggregate has more than one aggregate-source, then the ip-router policy aggr-
gen destination <aggr-dest-id> command should be repeated for each <aggr-src-id> .
Create an aggregate
route.
ip-router policy aggr-gen destination
<aggr-dest-id>
[source <aggr-src-id>
[filter
<filter-id>
|[network
<ipAddr-mask>
[exact|refines|between
<low-high>
]
[preference
<number>
|restrict]]]]