10-17-2009 09:45 AM - edited 03-04-2019 06:24 AM
hello friends,
pls explain as-override feature in brief if possible please give me the example
Solved! Go to Solution.
10-17-2009 10:20 AM
Hello Sourabh,
neigh x.x.x.x as-override allows to a PE router to change the private ASN used by a CE node on an eBGP session running on a VRF access link.
the private ASN is changed in the PE ASN.
another CE node on another VRF (=connected to another PE node) will see the eBGP route coming from first site with an AS path of:
provider-ASN provider-ASN
instead of:
provider-ASN site1-ASN
this allows to use the same private ASN on all sites of a customer.
That is a clear management advantage for a service provider.
This because BGP by default doesn't accept BGP routes with an AS path attribute that contains local AS number.
Hope to help
Giuseppe
10-17-2009 09:53 AM
Please refer to the documentation:
http://www.cisco.com/en/US/docs/ios/12_2/switch/command/reference/xrfscmd4.html#wp1034057
Regards
Edison.
10-17-2009 10:20 AM
Hello Sourabh,
neigh x.x.x.x as-override allows to a PE router to change the private ASN used by a CE node on an eBGP session running on a VRF access link.
the private ASN is changed in the PE ASN.
another CE node on another VRF (=connected to another PE node) will see the eBGP route coming from first site with an AS path of:
provider-ASN provider-ASN
instead of:
provider-ASN site1-ASN
this allows to use the same private ASN on all sites of a customer.
That is a clear management advantage for a service provider.
This because BGP by default doesn't accept BGP routes with an AS path attribute that contains local AS number.
Hope to help
Giuseppe
10-17-2009 08:20 PM
thank you...Giuseppe, for providing nice expln.
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