To configure provider edge (PE) routers to allow readvertisement of all prefixes containing duplicate autonomous system numbers (ASNs), use the neighbor allowas-in command in router configuration mode. To disable the readvertisement of the ASN of the PE router, use the no form of this command.
In this case we are overriding the loop prevention mechanism which is inherently built into the BGP protocol (i.e. eBGP). I think if you read the notes, they advise caution for this exact reason.
As best practice you should have filters in place for both sent and received prefixes. Of course there are ample ways this can be achieved with Cisco IOS. By doing so you will remove the risk of developing loops by some misconfiguration (on someones part), or a topology change (i.e. newly added networks/peers).
If you need more detail in how to do the filtering please don't hesitate to get back to us.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.