From: Echo Chan (echo.chan@xxxxxxxxx)
Date: Sat Sep 04 1999 - 00:23:20 GMT-3
Hi All and Yezdi,
Edwards' question is very good. You can't always disable synchronization in
all case. synchronization is useful and important for transit AS networks.
It is used to make sure that the external route is distributed over all
internal routers before it announce out to the outside world.
Therefore, if the route appear in all internal routers. It should be able to
announce to other AS by eBGP. I think Edwards is try to verify that. Right
??
Regards,
Chan Wai Sun
UUNET Hong Kong
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
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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