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In order to get AS info, you need to configure your router to include AS info. AS information collection is resource intensive, especially when configured for origin-AS. In case you are not interested in monitoring peering arrangements, disabling AS collection may improve NetFlow Analyzer performance. |
Enter the global configuration mode and issue the following commands to enable BGP routing and establish a BGP routing process:
Command | Purpose |
---|---|
router bgp as-number |
Enables the BGP routing process, which places the router in router configuration mode |
network network-number [mask network-mask]
[route-map route-map-name] |
Flags a network as local to this autonomous system and enters it to the BGP table |
BGP supports two kinds of neighbors: internal and external. Internal neighbors are in the same autonomous system; external neighbors are in different autonomous systems. Normally, external neighbors are adjacent to each other and share a subnet, while internal neighbors may be anywhere in the same autonomous system.
To configure BGP neighbors, issue the following command in router configuration mode:
Command | Purpose |
---|---|
neighbor {ip-address|peer-group-name}
remote-as as-number |
Specifies a BGP neighbor |
The following example shows how BGP neighbors on an autonomous system are configured to share information.
router bgp 109
network 131.108.0.0
network 192.31.7.0
neighbor 131.108.200.1 remote-as 167
neighbor 131.108.234.2 remote-as 109
neighbor 150.136.64.19 remote-as 99
In the example, a BGP router is assigned to autonomous system
109, and two networks are listed as originating in the autonomous
system. Then the addresses of three remote routers (and their
autonomous systems) are listed. The router being configured will share
information about networks 131.108.0.0 and 192.31.7.0 with the
neighboring routers. The first router listed is in a different
autonomous system; the second neighbor's remote-as
router
configuration command specifies an internal neighbor (with the same
autonomous system number) at address 131.108.234.2 and the
third neighbor's remote-as
router configuration command
specifies a neighbor on a different autonomous system.
If you have configured BGP on your network, and want Netflow to report on autonomous systems (AS info), issue the following command on the router in global configuration mode:
Command | Purpose |
---|---|
ip flow-export destination {hostname|ip_address}
9996 |
Exports the Netflow cache entries to the specified IP address. Use the IP address of the NetFlow Analyzer server and the configured Netflow listener port. The default port is 9996. |
ip flow-export {version} [peer-as
| origin-as] |
Exports NetFlow cache entries in the specified version format (5 or 7). If your router uses BGP, you can specify that either the origin or peer ASs are included in exports – it is not possible to include both. |
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