From: Brian McGahan (brian@cyscoexpert.com)
Date: Wed Sep 18 2002 - 23:56:24 GMT-3
http://www.cisco.com/warp/public/459/25.shtml
"Paths marked as "not synchronized" in the show ip bgp <longer-prefixes>
output. If BGP synchronization is enabled, which it is by default in
Cisco IOSR Software, there must be a match for the prefix in the IP
routing table in order for an internal (iBGP) path to be considered a
valid path. If the matching route is learned from an OSPF neighbor, its
OSPF router ID must match the BGP router ID of the iBGP neighbor. Most
users prefer to disable synchronization using the no synchronization BGP
subcommand."
r3#sh ip ro 200.1.1.0
Routing entry for 200.1.1.0/24
Known via "ospf 1", distance 110, metric 74, type extern 1
Redistributing via eigrp 1
Advertised by eigrp 1 metric 2000 100 255 1 1500
Last update from 100.1.23.2 on serial0, 00:15:37 ago
Routing Descriptor Blocks:
* 100.1.23.2, from 100.1.1.1, 00:15:37 ago, via serial0
Route metric is 74, traffic share count is 1
r3#sh ip bgp 200.1.1.0
BGP routing table entry for 200.1.1.0/24, version 3
Paths: (1 available, no best path)
Not advertised to any peer
Local
100.1.1.1 (metric 55) from 100.1.2.2 (100.1.2.2)
Origin incomplete, metric 0, localpref 100, valid, internal, not
synchronized
Originator: 100.1.1.1, Cluster list: 100.1.2.2
What does this all mean? It means that your current setup will not
work.
The RID is shown in the "from w.x.y.z" field under OSPF, and the
"(w.x.y.z)" field under BGP. As we see in the above example, 100.1.1.1
!= 100.1.2.2, therefore the prefix is not synchronized.
Either you must
1. fully mesh your iBGP sessions
2. use confederation
3. use another IGP besides OSPF
4. turn synchronization off
HTH
Brian McGahan, CCIE #8593
Director of Design and Implementation
brian@cyscoexpert.com
CyscoExpert Corporation
Internetwork Consulting & Training
http://www.cyscoexpert.com
Voice: 847.674.3392
Fax: 847.674.2625
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> hoon
> Sent: Wednesday, September 18, 2002 9:09 PM
> To: ccielab@groupstudy.com
> Subject: sync problem again
>
> hi, guys..
>
> i just have the same old sync problem issue about RR, RR-clients and
IGP.
> tried to find old threads about it but some had been deleted already.
>
> Well, this is it;
> i have R2 as a RR and R1, R3 as clients.
> They are running OSPF w/ the RID 100.1.1.1, 100.1.2.2, 100.1.3.3
> respectively which are each loopback ip addresses. ibgp neighbors are
> established w/ loopback ip addresses.
> Each bgp process is configured to be sync.
> One more loopback w/ 200.1.1.1/24 in R1 and not to be configured as
> 'network' command but redi into bgp by redi 'connect' w/ the route-map
> 'match interface loopback 2'
> Each serial is F/R and all nexthop info, serial, loopback ip address
are
> in IGP RT.
>
>
> lo :100.1.1.1 (ospf area1)
lo:100.1.2.2
> (ospf area 0) lo:100.1.3.3
> lo2: 200.1.1.1/24 -- R1 <----- serial -------> R2
<-----
> serial --------> R3
> (rr-client) 100.1.12.0/24
(rr)
> 100.1.23.0/24 (rr-client)
>
>
> R1 config.
>
> ospf 1
> router-id 100.1.1.1
> redi connect metric-type 1 route-map lo2 subnet
>
>
> bgp 1
> bgp router-id 100.1.1.1
> redi connect route-map lo2
> neigh 100.1.2.2 remote-as 1
> neigh 100.1.2.2 update-source loopback0
>
> route-map lo2
> match interface lo2
>
> R2 config
>
> ospf 1
> router-id 100.1.2.2
>
> bgp 1
> bgp router-id 100.1.2.2
> neigh rrc peer-group
> neigh rrc remote-as 1
> neigh rrc update-source loopback0
> neigh 100.1.1.1 peer-group rrc
> neigh 100.1.3.3 peer-group rrc
>
> R3 config
>
> ospf 1
> router-id 100.1.3.3
>
> bgp 1
> bgp router-id 100.1.3.3
> neigh 100.1.2.2 remote-as 1
> neigh 100.1.2.2 update-source loopback0
>
> r1 rt
>
> C 200.1.1.0/24 is directly connected, Loopback2
>
> bt
>
> BGP routing table entry for 200.1.1.0/24, version 2
> Paths: (1 available, best #1, table Default-IP-Routing-Table)
> Flag: 0x208
> Advertised to non peer-group peers:
> 100.1.2.2
> Local
> 0.0.0.0 from 0.0.0.0 (100.1.1.1)
> Origin incomplete, metric 0, localpref 100, weight 32768, valid,
> sourced, best
>
> r2 rt+bt
>
> O E1 200.1.1.0/24 [110/68] via 100.1.12.1, 02:17:32, Serial1.1
>
> r2#sh ip ro 200.1.1.0
> Routing entry for 200.1.1.0/24
> Known via "ospf 1", distance 110, metric 68, type extern 1
> Last update from 100.1.12.1 on Serial1.1, 00:05:03 ago
> Routing Descriptor Blocks:
> * 100.1.12.1, from 100.1.1.1, 00:05:03 ago, via Serial1.1
> Route metric is 68, traffic share count is 1
>
> r2#sh ip bgp 200.1.1.0
> BGP routing table entry for 200.1.1.0/24, version 4
> Paths: (1 available, best #1, table Default-IP-Routing-Table)
> Advertised to peer-groups:
> rrc
> Local, (Received from a RR-client)
> 100.1.1.1 (metric 49) from 100.1.1.1 (100.1.1.1)
> Origin incomplete, metric 0, localpref 100, valid, internal,
> synchronized, best
>
> r3 rt+bt
>
>
> O E1 200.1.1.0/24 [110/74] via 100.1.23.2, 00:21:54, serial 0
>
> r3#sh ip ro 200.1.1.0
> Routing entry for 200.1.1.0/24
> Known via "ospf 1", distance 110, metric 74, type extern 1
> Redistributing via eigrp 1
> Advertised by eigrp 1 metric 2000 100 255 1 1500
> Last update from 100.1.23.2 on serial0, 00:15:37 ago
> Routing Descriptor Blocks:
> * 100.1.23.2, from 100.1.1.1, 00:15:37 ago, via serial0
> Route metric is 74, traffic share count is 1
>
> r3#sh ip bgp 200.1.1.0
> BGP routing table entry for 200.1.1.0/24, version 3
> Paths: (1 available, no best path)
> Not advertised to any peer
> Local
> 100.1.1.1 (metric 55) from 100.1.2.2 (100.1.2.2)
> Origin incomplete, metric 0, localpref 100, valid, internal, not
> synchronized
> Originator: 100.1.1.1, Cluster list: 100.1.2.2
>
> the problem is on BT in r3 about n/w 200.1.1.0 which won't be
synchronized
> at all.
> i know that ospf rid and bgp rid should match somehow.
> and they seem to match
> r3#sh ip ospf da | in 200.1.1.0
> 200.1.1.0 100.1.1.1 940 0x80000006 0x429 0
>
> i found if R1 and R3 are full-meshed, then it would be synchronized
and
> also,
> static "ip route 200.1.1.0 255.255.255.0 100.1.1.1" on r3 would sync
it
> too.
>
> but why is the route not synchronized when it's advertized by RR?
> i don't get it.
> anybody helps me?
> thanks in advance.
This archive was generated by hypermail 2.1.4 : Mon Oct 07 2002 - 07:43:56 GMT-3