I am looking to implement few servers at different location with own ASN having prefix of PI resources of /22 going to divide into 2 x /23. I am unaware of what challenges I can face. As the 2 sites are geographically separated say SITE A and SITE B, but I am going to announce separate prefix of /23 with each site having my own ASN over different site. All the host/server at each location are going to perform different task.

So, Still do I need to implement iBGP or any IGP protocol to communicate between two sites A & B? Or it will be treated separate bgp as I am announcing different prefix at each site?

Will I face any issue to communicate between 2 site?

  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Apr 1, 2018 at 22:41
  • Sorry, but that didn't helped me, I added a comment below that answer and looking for reply if that way is possible to make the things work. Apr 3, 2018 at 5:17

1 Answer 1


Since you'll be doing eBGP at both locations, any update received will be subject to BGP loop prevention, which is - any prefix received with the local ASN present within its' AS-Path attribute, will be dropped. Hence, announcements from Site-A, will not reach Site-B.

Which might not be a problem after all, if your ISP advertises a default-route only, to you. Otherwise, yes - there's a problem.

Running iBGP across Internet can be tricky and IGP's impossible (no ISP will run IGP toward customer network). Hence, your best shot, might be some sort of tunnel (nowadays, preferably encrypted (some sort of VPN), but this's totally up to you). Withing such tunnel, you may run routing as you wish, just remember to setup the tunnel, using reachable addresses (such as p2p between you and your ISP, which are usually PA address space) to avoid running into the first issue I described.

Good luck!

  • Thanks for the information, as I am going to use completely separate prefix will it won't work only using allowas-in? As I am not using any similar services over the both site so I don't need any redundancy mechanism. Mar 12, 2018 at 2:46
  • @SaurabhSonar, then you need to have a connection between the sites, either a separate connections, or a tunnel between the sites. Alternatively, you could have a separate AS for each site, which could be the best option if you are not looking for any type of redundancy..
    – Ron Maupin
    Apr 3, 2018 at 5:42

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