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It is my understanding that in order to get an AS number from ARIN (https://www.arin.net/), one has to own a class C network of IP addresses.
It sounds like once an AS number is obtained from ARIN (and not one's local ISP), one can use the border gateway protocol (BGP) to independently announce a route to ones network. If I run BGP (using BIRD (http://bird.network.cz/) on ubuntu for example), who would BGP need to be connecting to to announce this? If my ISP gives me a static IP address, but does not want to do BGP with me (I think this is called iBGP or internal BGP), can I connect to external (or eBGP?) and announce my route to the global internet? It seems like this may be possible regardless of what my ISP wants me to do since BGP is a higher level protocol that runs on TCP. Is there a root BGP server list (similar to DNS)?
I'm just trying to figure out if I were able to obtain a class C network, could I host that redundantly with two cheap (250$/month) internet connections (each having a single static IP allocated to be from the ISP for my router), announcing the redundant routes and removing a dead route if that link goes down myself.
I'm aware that obtaining an AS number and a class C network of IP addresses may be fairly costly using IPv4, to the point where I may want to get ISPs with support for iBGP, however, I'm trying to understand the routing process and also plan for IPv6, where this may be more feasible.
user1748155
Posted 2016-08-18T20:26:04.640
Reputation: 151
You run BGP with your ISP (external to you, that's what eBGP means). If you have a consumer ISP, they probably do not support this. iBGP would be running BGP internally within your network. Unless you are an ISP you don't announce anything "to the Internet". There is a set of Networks that are the core, if you have a couple million spare dollars, you might get a connection, but for $250/mo you aren't going to find anyone that wants to run BGP with you. – MAP – 2016-08-19T09:25:03.383
I think part of my confusion was as follows: I thought that there was an open "internet core" of BGP peers that would accept route information from anyone. Since BGP runs over TCP and I can connect to the "internet core" via TCP with any internet connection, I should be able to give some routing information via BGP to the "internet core" routers, as long as I have an AS number and some IP addresses reserved to me. I was trying to figure out how to find out and connect to those "internet core" routers. – user1748155 – 2017-01-06T05:17:08.267
I think the reality is, even if the "internet core" routers would accept a route from me, it probably wouldn't ever work because the first hop, and any following hops in that route (all the way up to my router) that are not part of the "internet core" would not know about/understand the route, and would immediately just fail to route to me. I think the bottom line is that you need to have all routers in your route knowing about the route, otherwise it doesn't work. You can do BGP peering only with your directly connected peers. Is this correct? – user1748155 – 2017-01-06T05:20:37.070
I think you're catching on. Actually the term "Internet Core" refers to the really big ISPs that connect to one another and that smaller (but still big) ISPs buy their service from, then smaller ISPs might buy service from those second level ISPs, until the ISP you are connecting to provides your service. – MAP – 2017-01-08T21:57:57.357