From: Paglia, John (USPC.PCT.Hopewell) (JPaglia@NA2.US.ML.com)
Date: Thu Sep 26 2002 - 18:46:10 GMT-3
I have a situation that I'm a bit confused on...
bb1 |____R1____R3___R6___R4
|
r1: RIP only - BGP AS 7
r3: RIP/OSPF mutual redist. - BGP AS 7
r6: OSPF - NO BGP
r4: OSPF - BGP AS 7
Now someone posted advice that you should practice every bgp scenario w/
sync enabled, which seeme dlike great advice to me, so I tried it with this
scenario.
R1 peers to BB and gets BGP routes. R1, 3 and 4 are iBGP peers configured in
a full mesh, with R1 announcing 'next-hop-self'. Now since sync is on, I
want to get these BGP learned routes into my igp, so I promptly
redistributed them into the protocol running on the router that received
these routes, which is RIP running on R1. This does appear to get the routes
into the IGP's properly, as the routes appear on every router in the
network, and I am able to ping the routes from each router.
The bothersome point is that while the routes in the bgp table are
considered to be the 'best' route on r1 and r3, r4 isn't as fortunate. It
has all the routes in it's bgp table, but none of them are 'best'. When I
run 'sh ip b 192.168.10.1' it shows as being 'not synchronized', although
the route is on ospf on the router, the next-hop is in the routing table as
well, and I can ping both the network address and the next-hop address.
What can I do to have these routes show up as being the 'best' route on r4?
I am including relevant configs...please assist!
Most grateful,
John
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
R1:
router bgp 7
bgp redistribute-internal
bgp router-id 138.7.1.1
bgp log-neighbor-changes
aggregate-address 192.168.0.0 255.255.128.0
neighbor 138.7.3.3 remote-as 7
neighbor 138.7.3.3 ebgp-multihop 255
neighbor 138.7.3.3 update-source Loopback0
neighbor 138.7.3.3 next-hop-self
neighbor 138.7.4.4 remote-as 7
neighbor 138.7.4.4 ebgp-multihop 255
neighbor 138.7.4.4 update-source Loopback0
neighbor 138.7.4.4 next-hop-self
neighbor 150.100.1.2 remote-as 2
no auto-summary
R3:
router bgp 7
bgp router-id 138.7.3.3
bgp log-neighbor-changes
neighbor 138.7.1.1 remote-as 7
neighbor 138.7.1.1 ebgp-multihop 255
neighbor 138.7.1.1 update-source Loopback0
neighbor 138.7.4.4 remote-as 7
neighbor 138.7.4.4 ebgp-multihop 255
neighbor 138.7.4.4 update-source Loopback0
no auto-summary
R4:
router bgp 7
bgp router-id 138.7.4.4
bgp log-neighbor-changes
neighbor 138.7.1.1 remote-as 7
neighbor 138.7.1.1 ebgp-multihop 255
neighbor 138.7.1.1 update-source Loopback0
neighbor 138.7.3.3 remote-as 7
neighbor 138.7.3.3 ebgp-multihop 255
neighbor 138.7.3.3 update-source Loopback0
no auto-summary
r4# sh ip b
BGP table version is 1, local router ID is 138.7.4.4
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i192.168.0.0/17 138.7.1.1 100 0 i
* i192.168.10.0 138.7.1.1 0 100 0 254 i
* i192.168.11.0 138.7.1.1 0 100 0 254 i
* i192.168.20.0 138.7.1.1 0 100 0 254 i
* i192.168.21.0 138.7.1.1 0 100 0 254 i
* i192.168.100.0 138.7.1.1 0 100 0 254 i
* i192.168.101.0 138.7.1.1 0 100 0 254 i
* i192.168.102.0 138.7.1.1 0 100 0 254 i
* i192.168.103.0 138.7.1.1 0 100 0 254 i
r4#sh ip ro
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
138.7.0.0/16 is variably subnetted, 13 subnets, 4 masks
C 138.7.245.0/29 is directly connected, Serial0
O 138.7.245.2/32 [110/128] via 138.7.46.6, 00:46:20, Serial1
[110/128] via 138.7.245.5, 00:46:20, Serial0
O 138.7.245.5/32 [110/64] via 138.7.245.5, 00:46:20, Serial0
O 138.7.5.0/24 [110/65] via 138.7.245.5, 00:46:20, Serial0
C 138.7.4.0/24 is directly connected, Loopback0
O 138.7.6.0/24 [110/65] via 138.7.46.6, 00:46:20, Serial1
O E1 138.7.1.0/24 [110/374] via 138.7.46.6, 00:45:57, Serial1
O 138.7.3.0/24 [110/75] via 138.7.46.6, 00:46:21, Serial1
O 138.7.2.0/24 [110/129] via 138.7.46.6, 00:46:21, Serial1
[110/129] via 138.7.245.5, 00:46:21, Serial0
O IA 138.7.26.0/24 [110/128] via 138.7.46.6, 00:46:21, Serial1
O IA 138.7.22.0/24 [110/134] via 138.7.46.6, 00:46:22, Serial1
[110/134] via 138.7.245.5, 00:46:22, Serial0
C 138.7.46.0/24 is directly connected, Serial1
O 138.7.36.0/25 [110/74] via 138.7.46.6, 00:46:22, Serial1
O E1 192.168.10.0/24 [110/374] via 138.7.46.6, 00:09:46, Serial1
O E1 192.168.11.0/24 [110/374] via 138.7.46.6, 00:09:46, Serial1
O E1 192.168.21.0/24 [110/374] via 138.7.46.6, 00:09:25, Serial1
O E1 192.168.20.0/24 [110/374] via 138.7.46.6, 00:09:25, Serial1
O E1 192.168.102.0/24 [110/374] via 138.7.46.6, 00:09:25, Serial1
O E1 192.168.103.0/24 [110/374] via 138.7.46.6, 00:09:25, Serial1
O E1 192.168.100.0/24 [110/374] via 138.7.46.6, 00:09:25, Serial1
150.100.0.0/24 is subnetted, 2 subnets
C 150.100.2.0 is directly connected, Ethernet0
O E1 150.100.1.0 [110/374] via 138.7.46.6, 00:45:58, Serial1
O E1 192.168.101.0/24 [110/374] via 138.7.46.6, 00:09:25, Serial1
O E1 199.172.0.0/16 [110/374] via 138.7.46.6, 00:46:22, Serial1
O E1 192.168.0.0/17 [110/374] via 138.7.46.6, 00:09:27, Serial1
r4#sh ip b 192.168.10.1
BGP routing table entry for 192.168.10.0/24, version 0
Paths: (1 available, no best path)
Not advertised to any peer
254
138.7.1.1 (metric 374) from 138.7.1.1 (138.7.1.1)
Origin IGP, metric 0, localpref 100, valid, internal, not synchronized
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