Aggregating Routes Advertised To Bgp4 Neighbors - Foundry Networks Switch and Router Installation And Configuration Manual

6. Enter the AS numbers of the peers (sub-ASs) within the confederation in the Confederation Peers field.
Separate the AS numbers with spaces. You must specify all the sub-ASs contained in the confederation. All
the routers within the same sub-AS use IBGP to exchange router information. Routers in different sub-ASs
within the confederation use EBGP to exchange router information. You can specify a number from 1 –
65535.
7. Click the Apply button to apply the changes to the device's running-config file.
8. Select the Save link at the bottom of the dialog, then select Yes when prompted to save the configuration
change to the startup-config file on the device's flash memory.

Aggregating Routes Advertised to BGP4 Neighbors

By default, the Layer 3 Switch advertises individual routes for all the networks. The aggregation feature allows
you to configure the Layer 3 Switch to aggregate routes in a range of networks into a single CIDR number. For
example, without aggregation, the Layer 3 Switch will individually advertise routes for networks 207.95.1.0,
207.95.2.0, and 207.95.3.0. You can configure the Layer 3 Switch to instead send a single, aggregate route for
the networks. The aggregate route would be advertised as 207.95.0.0.
NOTE: To summarize CIDR networks, you must use the aggregation feature. The auto summary feature does
not summarize networks that use CIDR numbers instead of class A, B, or C numbers.
To aggregate routes, use either of the following methods.
USING THE CLI
To aggregate routes for 209.157.22.0, 209.157.23.0, and 209.157.24.0, enter the following command:
BigIron(config-bgp-router)# aggregate-address 209.157.0.0 255.255.0.0
Syntax: aggregate-address <ip-addr> <ip-mask> [as-set] [summary-only] [suppress-map <map-name>]
[advertise-map <map-name>] [attribute-map <map-name>]
The <ip-addr> and <ip-mask> parameters specify the aggregate value for the networks. Specify 0 for the host
portion and for the network portion that differs among the networks in the aggregate. For example, to aggregate
10.0.1.0, 10.0.2.0, and 10.0.3.0, enter the IP address 10.0.0.0 and the network mask 255.255.0.0.
The as-set parameter causes the router to aggregate AS-path information for all the routes in the aggregate
address into a single AS-path.
The summary-only parameter prevents the router from advertising more specific routes contained within the
aggregate route.
The suppress-map <map-name> parameter prevents the more specific routes contained in the specified route
map from being advertised.
The advertise-map <map-name> parameter configures the router to advertise the more specific routes in the
specified route map.
The attribute-map <map-name> parameter configures the router to set attributes for the aggregate routes based
on the specified route map.
NOTE: For the suppress-map, advertise-map, and attribute-map parameters, the route map must already be
defined. See "Defining Route Maps" on page 19-63 for information on defining a route map.
USING THE WEB MANAGEMENT INTERFACE
1. Log on to the device using a valid user name and password for read-write access. The System configuration
panel is displayed.
2. Click on the plus sign next to Configure in the tree view to expand the list of configuration options.
3. Click on the plus sign next to BGP in the tree view to expand the list of BGP option links.
December 2000
Configuring BGP4
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