I don't disagree with most of your points, but really think synch should be disabled in all cases at all times along with auto summary. It should be disabled by default and indeed shouldn't even be included as a configurable option.
At 11:28 AM 4/8/2002 -0400, you wrote: >It's not default for the same reason why unicast rpf (antispoofing) is >not default in ISO; because people are stupid, and under poor design, it >could produce very undesirable and hard to troubleshoot results. In >other words, if you don't know why you are disabling synchronization, >don't do it. > >Take the following scenario: A multihop iBGP link between routers (A) >and (B) in which a non-bgp IGP router (C) is routing packets between >them. Both BGP links are advertising full tables to each other, and, >under your suggested default config, would attempt to forward packets to >destinations that router C has no clue about. Then what does router C >do with these destinations? > >The answer, of course, is to set up a iBGP full mesh, and then to >disable synchronization , and if you are smart, design your network so >that your IGP learns only about downstream routes and set a default >route up to the core of your network. > >Anyway, the point being, sync is enabled by default because you really >should know what you are doing before you disable it. > >On Mon, 2002-04-08 at 10:44, MADMAN wrote: > > I can think one one good reason why you would disable sync, you can't > > redistribute 100K routes into ANY IGP. Why are you so concerned about > > disabling sync?? It should be default. > > > > Dave > > > > Jay wrote: > > > > > > BGP Rules of thumb: > > > > > > BGP advertised prefix must also exist in local IGP table. > > > iBGP learned prefix must also exist in local IGP table > > > -or use #no sync on iBGP learning router, but if you do, you'd sure as > > > hell better know why you disabled it. > > > > > > On Sun, 2002-04-07 at 09:22, Phil Barker wrote: > > > > Hi Group, > > > > > > > > Hope someone can help out with this as I don4t have > > > > access to my kit at the moment. > > > > > > > > I tried to set up my first BGP lab last week. > > > > I configured a full iBGP mesh, three routers connected > > > > in a triangle via serial lines. > > > > > > > > I set up (neighbour( statements on each router (Hope > > > > Radia can forgive the extra vowel !!!) and advertised > > > > the networks. > > > > > > > > I got the BGP table working but nothing was promoted > > > > to the main routing table, and therefore could4nt ping > > > > non directly connected interfaces. I tried various > > > > approaches like putting a default route in and running > > > > an IGP but still no promotion to the main table. > > > > > > > > Should this be possible with iBGP ? or is it a matter > > > > of loop avoidance i.e the AS Numbers won4t be > > > > prepended for the case of iBGP peers. > > > > > > > > Phil. > > > > > > > > __________________________________________________ > > > > Do You Yahoo!? > > > > Everything you'll ever need on one web page > > > > from News and Sport to Email and Music Charts > > > > http://uk.my.yahoo.com > > -- > > David Madland > > Sr. Network Engineer > > CCIE# 2016 > > Qwest Communications Int. Inc. > > [EMAIL PROTECTED] > > 612-664-3367 > > > > "Emotion should reflect reason not guide it" Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=40902&t=40741 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
