Re: 2 - BGP problems

From: ymadon@xxxxxxxxxxxxxx
Date: Fri Sep 03 1999 - 23:42:50 GMT-3


   

QUESTION 1: Have you disable synchronization.

 router bgp 1
 no synchronization

Question 2:
*> 192.192.2.0 132.4.7.5 0 100 0 (1034 1099) i

Can you ping 132.4.7.5 the BGP next hop.

In BGP the next hop is the neighbor that anounces the route (unlike IGPs)

Refer Halabi Pg 148. (Next Hop Attribute)

Regards
Yezdi

"Edward Taggart" <etaggart@pivot.net> on 04/09/99 07:58:10 AM

Please respond to "Edward Taggart" <etaggart@pivot.net>

To: ccielab@groupstudy.com
cc:

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 mes
h
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 tha
t
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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   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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