Hello. As promised, here are the links that discuss BCP's for ISP large scale routing, showing the use of OSPF and iBGP for a scalable and comprehensive internal routing policy:
ftp://ftp-eng.cisco.com/pfs/isp-workshops/BGP_Presentations/bgp-3.pdf ftp://ftp-eng.cisco.com/pfs/seminars/NANOG40-BGP-Techniques.pdf Cheers, Mark. ---------- Forwarded Message ---------- Subject: Re: [c-nsp] Loopback Advertise in OSPF Date: Thursday 28 February 2008 From: Mark Tinka <[EMAIL PROTECTED]> To: "Brandon Price" <[EMAIL PROTECTED]> On Thursday 28 February 2008, Brandon Price wrote: > Does anyone have links to some good examples of this > configuration? We normally cover this in regional workshops. Will send you a link to some slides that discuss this routing policy, tomorrow. > I am in the process of moving our small > ISP to dynamic routing and have read that this is the > preferred method. Yes, it is. It scales very well because your IGP (OSPF or IS-IS) doesn't have to carry all the prefixes your network needs to know. Just the BGP next-hops, i.e., Loopbacks, along with core interface IP addresses for reachability to those Loopbacks. In the case of OSPF, when used with Areas, the ability to scale well and keep the protocol light and fast, with minimal convergence times, is made possible. You would then use iBGP to carry all the prefixes you assigned to your customers, individually originating them from the edge routers your customers are connected to. BGP is well-suited to handling a large number of addresses (as we can see today on the Internet routing table). Using BGP in your core also means you can take advantage of the protocol's rich set of policy management features, e.g., BGP communities and other such attributes, to create a comprehensive internal routing policy. Cheers, Mark. -------------------------------------------------------
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