FAQ-Why Routes Cannot Be Imported When AS Numbers on the BGP/MPLS IP VPN Are the Same

Publication Date:  2015-05-06 Views:  136 Downloads:  0
Issue Description
Why Routes Cannot Be Imported When AS Numbers on the BGP/MPLS IP VPN Are the Same?
Solution
When the AS number in the Update message to be received by the EBGP-enabled device is the same as the AS number on the device, the device does not receive the Update message. This prevents routing loops. In some scenarios, the device needs to receive a Update message that carries the same AS number as the AS number on the device. In Hub and Spoke networking, when the Hub-PE and Hub-CE use EBGP, the Update message received by the Hub-CE contains the AS number of the Hub-PE. To prevent the Hub-PE from discarding such Update message, run the peer allow-as-loop command to set the number of times for the repeated AS number.

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