Re: 2 - BGP problems

From: Edward Taggart (etaggart@xxxxxxxxx)
Date: Sat Sep 04 1999 - 00:08:10 GMT-3


   
   On question #2, I removed the confederation from my three Autonomous
   Systems and the routes showed up in the routing table with a distance
   of 20. So, since my confederation of 3 Autonomous Systems included
   the AS that the route was sourced from then it must be treating that
   as a IBGP learned route and giving it a distance of 200.
   
   Still looking at question #1 though...
   
   ----- Original Message -----
   
   From: Edward Taggart
   
   To: grcitynet ; ccielab@groupstudy.com
   
   Sent: Friday, September 03, 1999 8:38 PM
   
   Subject: Re: 2 - BGP problems
   
   It's in it's own AS so it's EBGP, however I did setup a confederation
   between my 3 Autonomous Systems, I am going to try taking them out of
   a confederation and see if the routes get posted.
   
   
   
   I'm still unclear on the synchronization problem that seems to be
   happening with the 3 routers that are in the same AS though. I'll
   keep plugging away at it. Thanks for the help..!
   
   
   
   ----- Original Message -----
   
   From: grcitynet
   
   To: Edward Taggart ; ccielab@groupstudy.com
   
   Sent: Friday, September 03, 1999 7:06 PM
   
   Subject: Re: 2 - BGP problems
   
   Question 2
   
   
   
   EBGP has distance of 20 but IBGP has a distance of 200. If you are
   talking about IBGP in your question then OSPF with a distance of 110
   would be prefered.
   
   ----- Original Message -----
   
   From: Edward Taggart
   
   To: ccielab@groupstudy.com
   
   Sent: Friday, September 03, 1999 5:58 PM
   
   Subject: 2 - BGP problems
   
   I have 2 bgp problems that are driving me crazy.
   
   
   
   Question 1: I have 3 routers in the same AS. They are connected as
   follows:
   
   
   
       R3 <---> R2 <---> R5
   
   
   
   They all can reach each other fine through OSPF routes. R5 also has a
   loopback that is being redistributed via OSPF. I configured 2 peer
   statments on all routers providing a full mesh for the IBGP AS (all
   sessions show active). The network that the loopback's address
   resides in is being advertised to BGP by R5. When doing a "show ip
   bgp" it shows up in all 3 routers bgp table. However, R3 does not
   advertise the route to an external AS. When doing a "debug ip bgp
   update" on R3 I see that it is complaining that the loopbacks network
   is not synchronized. However, the loopbacks network is in the IGP
   routing table..
   
   
   
   Now, if I remove the peer statements between R3 & R5 and setup R2 with
   router-reflector-client statements, R3 advertises the route to the
   loopback to the external AS.
   
   
   
   How I understood it was that routers in the same AS do not need to be
   directly connected to their peers, they just need IP reachability to
   them and a full mesh peer configuration (or route a reflector). What
   am I missing?
   
   
   
   
   
   Qustion 2:
   
   If I have an OSPF route and BGP route on a router for the same
   network, what would keep the BGP route from injecting itself into the
   routing table given that BGP has a lower administrative distance than
   OSPF?
   
   
   
   The following is from a "show ip bgp" command
   
   *> 192.192.2.0 132.4.7.5 0 100 0 (1034 1099)
   i
   
   
   
   The following is from a show ip route from the same router as above:
   
   O E2 192.192.2.0/24 [110/20] via 132.4.8.2, 00:37:01, Serial1
   
   
   
   This particular router is in it's own AS so the 192.192.2.0 route is
   coming in from AS1034 then AS1099..
   
   
   
   Any help would be greatly appreciated. I'm looking through both
   Caslow's and Halabi's books and can't seem to find the answer to these
   problems.



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