At 03:54 PM 3/13/2003 +0000, Chris Headings wrote: >Good morning all, > >Does anyone out there know of either a good white paper or book that shows >some ISP OSPF designed networks? I am trying to find something that is more >geared towards service providers rather than corporate network LAN design.
Here are some thoughts. First off, keep your IGP as small as possible by pushing as much routing as possible in BGP. Ideally, you'll only use OSPF for loopback and link reachability. Use multiple areas only when the sheer amount of routers/interfaces demands it. Since you have few routes in OSPF, you won't be using multiple areas to enable address summarization. The amount of routers one has before one needs isolation via areas is a matter of some debate, but assuming you have some service provider class routers, should be at least in the 50-100 range at minimum and could likely approach much higher numbers. If you must use multiple areas, configure them as NSSA. You shouldn't have any externals in your network to begin with, but some odd situations tend to demand it and therefore if you must bring them in, NSSA will allow you some control over their flooding. Beyond that, try nanog archives for metric use guidelines if you intend to do some TE in OSPF (there are a few different approaches to metric use in IGPs). Also nanog is likely to have some timer tweaks that will be helpful in speeding convergence. Book wise, I've not seen one that covers IGP/BGP in tremendous detail. Howard Berkowitz has a pretty useful service provider book (Building Service Provider Networks / Wiley) that covers a variety of ISP oriented details that would likely be a good read if you are new to ISP networking, but most of the decent ISP best-practise like details from a router configuration perspective have usually been found at or near the NANOG community. Phillip Smith from Cisco has published his ISP Essentials set of guildelines as a book which has a lot of very useful information, but can also be found in pdf form. Pete >Thanks as always... > >Chris Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65345&t=65316 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
