From: Carlos G Mendioroz (tron@xxxxxxxxxxx)
Date: Mon Jul 01 2002 - 11:47:43 GMT-3
Hunt,
it's a tricky business, because you have to have a different
router-id for each ospf process, and it is being picked by IOS
in the order of creation of the processes.
If you take a look at the output, RouterB is picking router-id
172.16.0.17 for process 1 which is talking via network 172.16.0.0
to RouterC, when it should be using 193.16.0.1.
(Or whatever the BGP routerID of routerB)
You have to either pin the router-ids or order the process-ids
so that your "local subas" ospf process goes first.
Hunt Lee wrote:
>
> Hello Carlo,
>
> So do you mean that each OSPF routing domain has it's own Process ID
> & Area number:-
>
> 150.150.150.0/24---RTA ---RTB ---RTD---RTF
> | |
> RTC RTE
>
> RTA - RTB : OSPF Process 3, OSPF Area 3
> RTB - RTC : OSPF Process 1, OSPF Area 1
> RTB - RTD : OSPF Process 5, OSPF Area 0
> RTD - RTE : OSPF Process 2, OSPF Area 2
>
> Is this correct?
>
> All seems fine, except that RouterC can't sync. with most of it's BGP
> routes:
>
> *Mar 1 02:17:17.251 UTC: BGP: no valid path for 150.150.150.0/24
> *Mar 1 02:17:17.251 UTC: BGP: no valid path for 193.16.0.0/30
> *Mar 1 02:17:17.255 UTC: BGP: no valid path for 193.16.0.8/30
>
> RouterC#sh ip bgp
> BGP table version is 4, local router ID is 172.16.0.2
> 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
> * i150.150.150.0/24 193.16.0.2 0 100 0 (65530) i
> *>i172.16.0.0/30 172.16.0.1 0 100 0 i
> * i193.16.0.0/30 172.16.0.1 0 100 0 i
> * i193.16.0.8/30 172.16.0.18 0 100 0 (65532) i
> RouterC#
>
> RouterC#sh ip route
> 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, * -
> candidate default
> U - per-user static route, o - ODR
>
> Gateway of last resort is not set
>
> 172.16.0.0/30 is subnetted, 3 subnets
> O E2 172.16.0.16 [110/64] via 172.16.0.1, 00:53:41, Serial1
> O E2 172.16.0.12 [110/64] via 172.16.0.1, 00:53:26, Serial1
> C 172.16.0.0 is directly connected, Serial1
> 193.16.0.0/30 is subnetted, 1 subnets
> O E2 193.16.0.0 [110/10] via 172.16.0.1, 01:38:59, Serial1
> RouterC#
>
> And when I check the OSPF Router ID for RTB, it seems ok to me :)
>
> RouterB#sh ip ospf interface
> Ethernet0 is up, line protocol is up
> Internet Address 193.16.0.1/30, Area 3
> Process ID 3, Router ID 172.16.0.1, Network Type BROADCAST, Cost:
> 10
> Transmit Delay is 1 sec, State BDR, Priority 1
> Designated Router (ID) 150.150.150.1, Interface address 193.16.0.2
> Backup Designated router (ID) 172.16.0.1, Interface address
> 193.16.0.1
> Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit
> 5
> Hello due in 00:00:04
> Index 1/1, flood queue length 0
> Next 0x0(0)/0x0(0)
> Last flood scan length is 2, maximum is 4
> Last flood scan time is 0 msec, maximum is 4 msec
> Neighbor Count is 1, Adjacent neighbor count is 1
> Adjacent with neighbor 150.150.150.1 (Designated Router)
> Suppress hello for 0 neighbor(s)
> Serial0 is up, line protocol is up
> Internet Address 172.16.0.1/30, Area 1
> Process ID 1, Router ID 172.16.0.17, Network Type POINT_TO_POINT,
> Cost: 64
> Transmit Delay is 1 sec, State POINT_TO_POINT,
> Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit
> 5
> Hello due in 00:00:06
> Index 1/1, flood queue length 0
> Next 0x0(0)/0x0(0)
> Last flood scan length is 3, maximum is 5
> Last flood scan time is 0 msec, maximum is 4 msec
> Neighbor Count is 1, Adjacent neighbor count is 1
> Adjacent with neighbor 172.16.0.2
> Suppress hello for 0 neighbor(s)
> Serial1 is up, line protocol is up
> Internet Address 172.16.0.17/30, Area 0
> Process ID 5, Router ID 193.16.0.1, Network Type POINT_TO_POINT,
> Cost: 64
> Transmit Delay is 1 sec, State POINT_TO_POINT,
> Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit
> 5
> Hello due in 00:00:04
> Index 1/1, flood queue length 0
> Next 0x0(0)/0x0(0)
> Last flood scan length is 1, maximum is 3
> Last flood scan time is 0 msec, maximum is 0 msec
> Neighbor Count is 1, Adjacent neighbor count is 1
> Adjacent with neighbor 193.16.0.9
> Suppress hello for 0 neighbor(s)
>
> hostname RouterA
> !
> !
> interface Loopback0
> ip address 150.150.150.1 255.255.255.0
> !
> interface Ethernet0
> description Eth to RouterB
> ip address 193.16.0.2 255.255.255.252
> !
> router ospf 3
> log-adjacency-changes
> network 193.16.0.0 0.0.0.7 area 3
> !
> router bgp 65530
> bgp log-neighbor-changes
> bgp confederation identifier 1
> bgp confederation peers 65531
> network 150.150.150.0 mask 255.255.255.0
> neighbor 193.16.0.1 remote-as 65531
> no auto-summary
>
> -------------------------------------------------
>
> hostname RouterB
> !
> !
> interface Ethernet0
> description Eth to RouterA
> ip address 193.16.0.1 255.255.255.252
> !
> interface Serial0
> description Serial to RouterC
> ip address 172.16.0.1 255.255.255.252
> clockrate 64000
> !
> interface Serial1
> description Serial to RouterD
> ip address 172.16.0.17 255.255.255.252
> !
> router ospf 5
> log-adjacency-changes
> redistribute ospf 1 subnets
> redistribute ospf 3 subnets
> network 172.16.0.16 0.0.0.3 area 0
> !
> router ospf 1
> log-adjacency-changes
> redistribute ospf 5 subnets
> redistribute ospf 3 subnets
> network 172.16.0.0 0.0.0.3 area 1
> !
> router ospf 3
> log-adjacency-changes
> redistribute ospf 5 subnets
> redistribute ospf 1 subnets
> network 193.16.0.0 0.0.0.3 area 3
> !
> router bgp 65531
> bgp log-neighbor-changes
> bgp confederation identifier 1
> bgp confederation peers 65530 65532
> network 172.16.0.0 mask 255.255.255.252
> network 193.16.0.0 mask 255.255.255.252
> neighbor 172.16.0.2 remote-as 65531
> neighbor 172.16.0.18 remote-as 65532
> neighbor 193.16.0.2 remote-as 65530
> no auto-summary
> !
> -------------------------------------------------------------------
>
> RTC
>
> interface Serial1
> description Serial to RouterB
> ip address 172.16.0.2 255.255.255.252
> no ip directed-broadcast
> !
> router ospf 1
> network 172.16.0.0 0.0.0.3 area 1
> !
> router bgp 65531
> bgp confederation identifier 1
> neighbor 172.16.0.1 remote-as 65531
>
> --------------------------------------------------------------------
>
> RTD
>
> !
> interface Ethernet0
> description Eth to RouterF
> ip address 193.16.0.9 255.255.255.252
> no ip directed-broadcast
> !
> interface Serial0
> description Serial to RouterE
> ip address 172.16.0.14 255.255.255.252
> no ip directed-broadcast
> no ip mroute-cache
> no fair-queue
> clockrate 64000
> !
> interface Serial1
> description Serial to RouterB
> ip address 172.16.0.18 255.255.255.252
> no ip directed-broadcast
> clockrate 64000
>
> router ospf 5
> redistribute ospf 2 subnets
> network 172.16.0.16 0.0.0.3 area 0
> !
> router ospf 2
> redistribute ospf 5 subnets
> network 172.16.0.12 0.0.0.3 area 2
> !
> router bgp 65532
> bgp log-neighbor-changes
> bgp confederation identifier 1
> bgp confederation peers 65531
> network 193.16.0.8 mask 255.255.255.252
> neighbor 172.16.0.13 remote-as 65532
> neighbor 172.16.0.17 remote-as 65531
> neighbor 193.16.0.10 remote-as 2
> no auto-summary
> !
>
> ---------------------------------------------------------------
>
> RTE
>
> interface Serial0
> description Serial to RouterD
> ip address 172.16.0.13 255.255.255.252
> no fair-queue
> !
> router ospf 2
> network 172.16.0.12 0.0.0.3 area 2
> !
> router bgp 65532
> bgp confederation identifier 1
> neighbor 172.16.0.14 remote-as 65532
> no auto-summary
>
> ----------------------------------------------------------------
>
> RTF
>
> interface Ethernet0
> description Eth to RouterD
> ip address 193.16.0.10 255.255.255.252
> no ip mroute-cache
> no ip route-cache
> !
> !
> router bgp 2
> neighbor 193.16.0.9 remote-as 1
> no auto-summary
>
> So what's wrong?? Any ideas will be greatly apprecatied =^o^=
>
> Thanks!!
>
> Regards,
> Hunt
>
> Well, that's not what I'm saying, but yes, if that were the case,
> then
> that particular route would show on RTC. But I guess some other
> routes
> could vanish now from RTE. (You can not have the same router ID for
> two different routers...)
>
> Another way of doing it is having one OSPF routing domain for each
> confed sub-as, and another for inter-sub-as routing, and
> redistributing
> between them. All those are hacks for lab requirements, not real
> world alternatives, of course :-)
>
> Michael Popovich wrote:
> >
> > So you would say that RTB's BGP ID needs to be the same as RTD's
> OSPF
> > ID?
> >
> > I am unclear how 172.16.0.12 is getting into OSPF. You said it was
> > advertised by RTD in BGP. Can I assume it is also advertised in
> OSPF
> on
> > the same router?
> >
> > MP
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf
> Of
> > Carlos G Mendioroz
> > Sent: Tuesday, June 25, 2002 6:07 AM
> > To: Hunt Lee
> > Cc: ccielab@groupstudy.com
> > Subject: Re: Sync. problem in BGP
> >
> > In a nutshell, iBGP sync when the IGP is OSPF requires not only
> that
> > the received route is already in the FIB (routing table) but also
> > that the OSPF originator's ID is the same as the iBGP neighbour's
> ID.
> >
> > This creates problems especially with route reflectors, but also
> > when OSPF crosses AS borthers like in confeds.
> >
> > Hunt Lee wrote:
> > >
> > > Okay folks, I'm back as I have bummed into another problem last
> nite
> > > =)
> > >
> > > 150.150.150.0/24---RTA ---RTB ---RTD---RTF
> > > | |
> > > RTC RTE
> > >
> > > RTA, B, C, D, & E are in a Confederation called AS 1, in which:-
> > >
> > > RTA is sub-AS 65530
> > > RTB & RTC are both in sub-AS 65531
> > > RTD & RTE are both in sub-AS 65532
> > >
> > > RTF is in AS 2
> > >
> > > RTB, C, D & E are running OSPF as IGP. And OSPF is being
> > > redistributed into BGP at RTB.
> > >
> > > The network i172.16.0.12/30 is being advertised into BGP by BGP
> > > "network" command on RTD. i172.16.0.13 & .14 are the interfaces
> IP
> > > for RTD & RTE.
> > >
> > > Ok, here is the thing. RTC just can't see this link via BGP (it
> kept
> > > on saying it's not sync), even though it is reachable via OSPF.
> With
> > > OSPF, shouldn't BGP think that it is sync, and installs it as
> best
> > > route?
> > >
> > > Am I missing something here?
> > >
> > > RouterC#sh ip bgp
> > > BGP table version is 8, local router ID is 172.16.0.2
> > > 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
> > > * i150.150.150.0/24 193.16.0.2 0 100 0
> (65530)
> i
> > > *>i172.16.0.0/30 172.16.0.1 0 100 0 ?
> > > * i172.16.0.12/30 172.16.0.18 30 100 0 ?
> > > *>i172.16.0.16/30 172.16.0.1 0 100 0 ?
> > > *>i193.16.0.0/30 172.16.0.1 0 100 0 ?
> > > * i193.16.0.8/30 172.16.0.18 0 100 0
> (65532)
> i
> > >
> > > RouterC#sh ip bgp 172.16.0.12/30
> > > BGP routing table entry for 172.16.0.12/30, version 0
> > > Paths: (1 available, no best path)
> > > Not advertised to any peer
> > > Local
> > > 172.16.0.18 (metric 128) from 172.16.0.1 (193.16.0.1)
> > > Origin incomplete, metric 30, localpref 100, valid,
> internal,
> > > not synchronized, ref 2
> > >
> > > RouterC#sh ip route
> > > 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, * -
> > > candidate default U - per-user static route, o - ODR
> > >
> > > Gateway of last resort is not set
> > >
> > > 172.16.0.0/30 is subnetted, 3 subnets
> > > O 172.16.0.16 [110/128] via 172.16.0.1, 01:43:32, Serial1
> > > O 172.16.0.12 [110/192] via 172.16.0.1, 01:43:32, Serial1
> <--
> > > but it is reachable via OSPF ??
> > > C 172.16.0.0 is directly connected, Serial1
> > > 193.16.0.0/30 is subnetted, 1 subnets
> > > O 193.16.0.0 [110/74] via 172.16.0.1, 01:43:32, Serial1
> > > RouterC#
> > >
> > > Thanks all!
> > >
> > > H.
> > >
> > > http://www.sold.com.au - SOLD.com.au
> > > - Find yourself a bargain!
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