we have 2 co-operate sites. Each co-operate site has 2 different ISP's. Each co-operate site has an ASN number with /24 subnet. RIPE donot want to have 2 sites of the same company to have 2 ASN numbers. they have told us to to remove the ASN number on one site. As we have sites with 2 different ISP with dedicated link, we want to run the BGP so that we can take the beniefit of redundancy. How can we use one ASN number to run the BGP on these 2 sites?
public AS numbers are becoming rare so the RIRs are very careful in assigning them.
You have two sites and each site is connected to two different ISPs.
Each site advertises its own /24 and this is fine a network of this size can travel over the internet.
I guess your two sites are not directly connected by any means otherwise implementation would be easy.
There is a trick to make the two sites communicate even if they use the same AS number:
on each eBGP session to the ISPs you need to add
neighbor isp-x-y allow-as-in 1
in this way the advertisement coming from the other site can be accepted and installed in the routing table
note: if you use prepending you need to provide as parameter the maximum number of times your ASN can appear on routes coming from the other side: you need to change the 1 to the number you need to accept routes in any case.
However, in the long term I would consider to buy an EoMPLS service between the two sites so that you can merge them and use your routing protocols over it.
If you do so you can advertise both subnets on both sites using other tools to make one site preferred for subnet A and one preferred for subnet B.
The ISP does not need to to change anything because the allow-as-in command allows an EBGP speaking router to accept an EBGP advertised route with it's own AS number in it. The ISP does not need to do this. Only you need to do it at Site A & B.
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.