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Thread Index [isp-bgp] Re: Smaller ISP Network Design Question
Personally, I'd either grow to four routers per city (one to upstream, one to other city, two handling access links and infrastructure services) or consolidate to one router per city (two routers in the layout you present means more complexity and not necessarily much redundancy; the tradeoff may end up negative). Keep in mind that your BGP announcements out control your traffic flow in, and the BGP announcements you receive control your traffic flow out. Use that to plan your routing patterns and implementation. You will probably not get perfect isolation of the two cities/two upstreams without aggressive tuning, which may not be worthwhile anyway. In fact, some amount of "wrong pipe" routing may be good for testing purposes, and to minimize the severity of a reconvergence event. You may find that you don't even need to receive any routes from your provider. A carefully designed set of static routes, redistributed within a city, may cover your outbound policy sufficiently. Anthony Guida wrote: Hello - I work for a smaller ISP which has 2 offices in different locations in the midwest region. We currently get all of our upstream access through our CHI office which is multihomed to 2 different ISPs. But in the next month we will be disconnecting one of the ISPs in our CHI office and adding one to our DNV office. So we now will have 2 different exit points in our network. I would like to have a network constituted with 4 routers, 2 Edge and 2 Core routers connected on iBGP, and each Edge router is connected in eBGP to ISPs (ISP1 and ISP2). This is what I have in mind so far: CHI Edge Rtr 1-------ISP 1 (Announces own /21) | | CHI Core Rtr 1 | | iBGP | | DNV Core Rtr 2 | | DNV Edge Rtr 2-------ISP 2 (Announces own /21) The question I have is whether or not this is a good design? Currently the DNV Core router is sending all of its upstream traffic to the CHI Core Rtr and then over to the CHI Edge and out to the Internet. The DNV Core router is barely being utilized and now I am getting pressed by my directors to add an Edge router to the DNV office so we can have a similar setup as our CHI office. I am not sure if this design will provide us with more redundancy or just an extra hop each packet has to take. One more thing to note, the CHI Edge will only handle CHI upstream traffic and the DNV Edge will only handle DNV upstream traffic. If ISP 2 were to go down, all traffic would be routed through ISP 1 and vice-versa. To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
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