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Irish BGP peers?

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  • 26-03-2021 12:07pm
    #1
    martco
    Registered Users Posts: 424 ✭✭


    I'm attempting to teach myself up on networking for a bit of a career shift, but I find it near impossible to retain theoretical info unless I can stick it to something practical real life! So I'm trying to learn about BGP and my practical learning fake project is to be able to go thru the motions to stand up a disaster recovery site at a very large and well known cloud services provider in Clonshaugh for my new imaginary fake E-Bank....so I'll need to configure BGP

    in trying to understand basics practicals of BGP I've been digging around on bgp.he.net to get a feel for the real live infrastructure

    - My understanding is that BGP is a very manual setup, the peering isn't automagic, real humans involved and there's a large degree of trust involved. But how does this happen in reality tho? What drives an org to seek out peers, what's in it for them?

    - Can the assumption be that if a well known Irish Telco have, say, 8x peers listed that those 8 peers are likely to be actual customers of the Telco?

    - I noted that Irish Telcos don't appear to have other Irish Telcos as peers, why?

    - I noted that some well known Irish orgs only seem to have 1x peer, does that mean they have a single point of failure?

    appreciate any pointers ye can offer


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    #2
    KeRbDoG
    Registered Users Posts: 4,223 ✭✭✭KeRbDoG


    martco wrote: »
    I'm attempting to teach myself up on networking for a bit of a career shift, but I find it near impossible to retain theoretical info unless I can stick it to something practical real life! So I'm trying to learn about BGP and my practical learning fake project is to be able to go thru the motions to stand up a disaster recovery site at a very large and well known cloud services provider in Clonshaugh for my new imaginary fake E-Bank....so I'll need to configure BGP

    in trying to understand basics practicals of BGP I've been digging around on bgp.he.net to get a feel for the real live infrastructure

    - My understanding is that BGP is a very manual setup, the peering isn't automagic, real humans involved and there's a large degree of trust involved. But how does this happen in reality tho? What drives an org to seek out peers, what's in it for them?
    From my limited experience, networks peer with other networks who people on your network shift a lot of traffic to/from. Think of Eir peering with Google/Facebook/Microsoft etc.
    Why do it? Its usually beneficial for both. For the Googles etc the user experiance of tohse on the network/ISP they peer to is usually better, more bandwidth, lower pings etc. For the ISP, kinda the same. Users see that YouTube is good'n'fast etc.
    martco wrote: »
    - Can the assumption be that if a well known Irish Telco have, say, 8x peers listed that those 8 peers are likely to be actual customers of the Telco?
    Could be customers of that telco or like the answer before, people on that telco connect to those peering companies quite often.
    martco wrote: »
    - I noted that Irish Telcos don't appear to have other Irish Telcos as peers, why?
    People on Eir tend not to use services from Virgin Media, no real benefit for either.
    martco wrote: »
    - I noted that some well known Irish orgs only seem to have 1x peer, does that mean they have a single point of failure?
    appreciate any pointers ye can offer


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    #3
    rogue-entity
    Registered Users Posts: 1,647 ✭✭✭rogue-entity


    martco wrote: »
    - My understanding is that BGP is a very manual setup, the peering isn't automagic, real humans involved and there's a large degree of trust involved. But how does this happen in reality tho? What drives an org to seek out peers, what's in it for them?
    Automatic peering can happen at exchange points, but it depends on where a network is connected and the policies of the other networks (autonomous systems), otherwise it is manual as you said. There is a degree of trust involved, but sensible admins would apply filtering policies at the border routers.

    Peering happens when one or more networks agree to exchange traffic between each other's networks by exchanging routes to networks they are able to reach and there are different types of peering relationships depending on the network.

    An ISP like Eir will be a Tier3 provider, they only have end customers and will peer with someone larger to provide transit to the rest of the Internet, the trouble is this comes at a cost because the amount of data they send, vs the amount of data sent to them, will not be equal and the smaller party always pays. Typically an ISP would be incentivised to peer with other networks at an exchange point, a location where multiple networks are connected to the same local area network and can establish connections with each other over that network. By peering with other networks an ISP can route traffic direct to them, often for no extra cost, instead of paying their transit provider to do it.

    In Ireland, the only exchange point is INEX. An ISP can pay INEX for a connection and then arrange with other members of the exchange to peer with them, for example, with other ISPs, or with large content or cloud providers also peering at that exchange. An ISP can also peer with their transit provider via INEX but they may be more likely to have a cross-connect (a direct connection) between their router, and the router of their provider's.
    martco wrote: »
    - Can the assumption be that if a well known Irish Telco have, say, 8x peers listed that those 8 peers are likely to be actual customers of the Telco?
    They may be upstream/transit providers providing the Telco with connectivity to the rest of the Internet, they may be paying the ISP for transit themselves or they may be networks where the ISP feels it is beneficial to peer with, for example, Amazon or Netflix.
    martco wrote: »
    - I noted that Irish Telcos don't appear to have other Irish Telcos as peers, why?
    They might not exchange much traffic between themselves to justify it.
    martco wrote: »
    - I noted that some well known Irish orgs only seem to have 1x peer, does that mean they have a single point of failure?
    No, because they could be connected at multiple locations; for example if they have a port on INEX LAN1 and on INEX LAN2, and peer with another network on each, they now have two connections. They may also be able to reach that network via a transit provider as a backup even if that route is a bit longer.
    martco wrote: »
    appreciate any pointers ye can offer
    If you're looking to set something up on a lab to play around with, you could setup a pair of Linux VMs and use private AS numbers and IP space as in this example:
    https://claer.github.io/network/bgp/bird/openbsd/debian/2016/05/09/bgp-3-as.html

    If you're looking for more 'real world' experience, that is also possible but there's a number of prerequisites


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