Great reply, Thanks!
>From: "Howard C. Berkowitz" >Reply-To: "Howard C. Berkowitz" >To: [EMAIL PROTECTED] >Subject: Provider backbone engineering (was: Logic and Lab Rats) [7:44743] >Date: Wed, 22 May 2002 15:42:01 -0400 > >At 7:03 PM +0000 5/22/02, Cisco Nuts wrote: > >Could you elaborate on the "backbone engineering is at a level far > >more specialized and complex than the CCIE level, and there haven't > >been formalized ways to learn it." > > > >I would love to know more about what you actually mean? > > > >Thank you. > > > >Regards. > > > >:-) well, my book on the subject, "Building Service Provider >Networks," should be about to ship. > >Seriously, let's talk about several areas, beginning with BGP. Every >BGP scenario I've seen or or heard of in the CCIE context, at best, >looks at an extremely simple configuration with rules NEVER used in >the real world. A few contrasts: > >-- in the real world, it's VERY rare to redistribute between a dynamic IGP > and BGP. Sure, there are exceptions, but they are VERY carefully >chosen. > A provider backbone CANNOT survive having 100,000-plus routes in its > IGP, nor should it. >-- In provider use, the main purpose of the IGP (or multiple instances of >an > IGP) is to maintain connectivity among BGP routers. You may have a > separate IGP instance for each POP or group of POPs. >-- To connect customers, there is MUCH more use of static and default >routes. > You could not possibly run a provider network with the CCIE lab rule >of > no statics or defaults. >-- AS paths are longer and more complex than you can create with six or > so routers. >-- There's a HUGE amount of things to be concerned with that aren't >strictly > configuration, such as justifying/obtaining/managing address space, > intercarrier relationships involving both economics and cooperative > troubleshooting, DNS management, protecting against distributed denial > of service, etc. >-- BGP communities are far more important than in typical scenarios. > You need to know why and when to set up your own, learn the values of > communities set by other AS and under what circumstances you should >act > on them, etc. >-- You may be dealing literally thousands of routers in your own network, > interconnected with thousands of enterprise networks. You may also >have > a complex ATM, SONET, MPLS, or other intelligent sub-IP technology >that > must coordinate with the IP. >-- There's a different viewpoint on convergence. It's generally accepted > among large providers and researchers that the worldwide "BGP table" > never truly converges -- changes come too fast. We have to work in >that > environment. >-- Customers frequently multihome in ways that require coordinating between > their providers, even when those providers are competitors. >-- As opposed to an enterprise network where SOMEBODY is in control, the > provider space involves cooperative anarchy. One AS fouling up its > configuration can and has had worldwide effects. > > >These are just a start. There are other people that can comment on >some of the differences. Peter van Oene (yes, I'm volunteering you) >is one with lots of good experience. There are others, and this >actually might be an interesting thread. >-- >"What Problem are you trying to solve?" >***send Cisco questions to the list, so all can benefit -- not >directly to me*** >******************************************************************************** >Howard C. Berkowitz [EMAIL PROTECTED] >Chief Technology Officer, GettLab/Gett Communications >http://www.gettlabs.com >Technical Director, CertificationZone.com http://www.certificationzone.com >"retired" Certified Cisco Systems Instructor (CID) #93005 _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=44875&t=44875 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
