From: Chris Lewis (chrlewiscsco@gmail.com)
Date: Thu Mar 09 2006 - 10:53:41 GMT-3
When I did this the extra step for OSPF of checking the router ID of the
OSPF supplied prefix (sho ip ospf databse) and the router ID of the BGP
route (sho ip bgp a.b.c.d) matched.
If the OSPF route is originated on one router, then brought in to BGP on
another, the router IDs of the prefixes will not match between these two
protocols and therefore won't be installed by BGP. On your config it looks
to me like OSPF originates 20.20.20.20 on SW2 and it is brought in to BGP on
R2, so the router IDs of the prefixes (who originated them) will not match
and therefore the prefixes fail this additional BGP/OSPF check.
Chris
On 3/8/06, Mushtaq A. Khan <mak.ccie2b@gmail.com> wrote:
>
>
> As I mentioned previously in my email I was able to complete this
> requirement using BGP Confederation but in order to do this I had to
> configure 3 new ASs (65001, 65002, 65003) which were mentioned in the
> requiment. My question is that are we allowed to do this in the lab exam.
> Aren't configuring something that is not asked? Can someone comment on
this?
> Also, it would be very helpful if someone give me a tip to get this
> requirement done using route-reflector option with Synchronization enable
> for AS100.
>
> Thanks,
> Mushtaq
>
> On 3/8/06, Mushtaq A. Khan <mak.ccie2b@gmail.com> wrote:
> >
> > Chris,
> >
> > Yes, both BGP and OSPF router-ids matches.
> >
> > Mushtaq
> >
> >
> > On 3/8/06, Chris Lewis <chrlewiscsco@gmail.com > wrote:
> > >
> > > For the routes in question, does teh OSPF router ID match the BGP
> > > router ID?
> > >
> > > Chris
> > >
> > >
> > > On 3/8/06, Mushtaq A. Khan <mak.ccie2b@gmail.com > wrote:
> > > >
> > > > Nick,
> > > >
> > > > Thanks for the tip but if you notice in my configuration I have
> > > > already
> > > > redistributed BGP into IGP in their respective peer routers in AS100
> > > > to put
> > > > these prefixes in the route table. When I checked the routes table
> > > > all three
> > > > routes shows there as well but this is still not working.
> > > >
> > > > Mushtaq
> > > >
> > > >
> > > > On 3/8/06, Popgeorgiev Nikolay < nikolay.popgeorgiev@siemens.com>
> > > > wrote:
> > > > >
> > > > > Dear Mushtaq,
> > > > >
> > > > >
> > > > > I didn't go really through all your post but I can tell you how I
> > > > did this
> > > > > thing and what problems I faced in a similar task:
> > > > >
> > > > > I used RR in AS 100, R1 as a route reflector and R2 as its client.
> > > > > Because the requirement says do't disable synchronization, in
> > > > order for R1
> > > > > for example to put network 20.20.20.20 into its routing table, it
> > > > has to
> > > > > have this route known already via IGP or static or connected.
> > > > > So my solution is to redistribute BGP into IGP on router R2. This
> > > > is not a
> > > > > very clever thing to do if you have many routes coming from BGP
> > > > but in this
> > > > > case helps :)
> > > > >
> > > > >
> > > > > Try it and if I have missed something in your explanations sorry
> > > > about
> > > > > that
> > > > >
> > > > > Best,
> > > > > Nick
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > -----Original Message-----
> > > > > From: Mushtaq A. Khan [mailto:mak.ccie2b@gmail.com]
> > > > > Sent: Wednesday, March 08, 2006 7:59 AM
> > > > > To: ccielab@groupstudy.com
> > > > > Subject: EBGP peer is not advertising prefixes from other EBGP
> > > > peer while
> > > > > synchronization is enabled in Transit ASs
> > > > >
> > > > > Hi Team,
> > > > >
> > > > > I have a scenario as shown below.
> > > > >
> > > > > SW2(AS200) ----(RIP)-----R2(AS100)
> > > > > \
> > > > > (OSPF)
> > > > > \
> > > > > R1(AS100)
> > > > > -----(OSPF)----R6(AS600)
> > > > > /
> > > > > (OSPF)
> > > > > /
> > > > > R5(AS600)-----EIGRP-----R3(AS100)
> > > > >
> > > > > The task is to advertise the following prefixes in BGP ONLY within
> > > > their
> > > > > respective ASs and these should be exchanged between all AS's.
> > > > >
> > > > > 20.20.20.20(SW2)
> > > > > 5.5.5.5 (R5)
> > > > > 6.6.6.6 (R6)
> > > > >
> > > > > AS100 should provide transit path between the above prefixes and
> > > > MUST not
> > > > > disable synchronization and use minimal number of BGP speakers.
> > > > >
> > > > > One solution to above requirement is to use BGP confederation
> > > > within
> > > > > AS100.
> > > > > I tried to solve this using route reflector and facing difficulty:
> > > > I
> > > > > noticed
> > > > > R6 is able to see all 3 prefixes in its BGP table. However, R5 and
> > > > SW2
> > > > > can't
> > > > > see each other prefixes. I tried different options but with no
> > > > luck.
> > > > > Anyone
> > > > > has any clue to resolve this issue here.
> > > > >
> > > > > All relevent configuration are given below:
> > > > >
> > > > > R2#sh run | beg router bgp
> > > > > router bgp 100
> > > > > synchronization
> > > > > bgp log-neighbor-changes
> > > > > neighbor 172.16.20.10 remote-as 200
> > > > > neighbor 172.16.101.1 remote-as 100
> > > > > neighbor 172.16.101.1 update-source Loopback102
> > > > > no auto-summary
> > > > > !
> > > > > R2#sh run | beg router ospf|route-map
> > > > > router ospf 1
> > > > > log-adjacency-changes
> > > > > redistribute rip subnets
> > > > > redistribute bgp 100 subnets route-map BGPtoOSPF
> > > > > network 172.16.102.1 0.0.0.0 area 20
> > > > > network 172.16.123.2 0.0.0.0 area 0
> > > > > !
> > > > > ip prefix-list BGP-Route seq 5 permit 20.20.20.0/24
> > > > > !
> > > > > route-map BGPtoOSPF permit 10
> > > > > match ip address prefix-list BGP-Route
> > > > >
> > > > > R2#sh ip bgp | beg Network
> > > > > Network Next Hop Metric LocPrf Weight Path
> > > > > * i5.5.5.0/24 172.16.35.5 0 100 0 500 i
> > > > > r>i6.6.6.0/24 172.16.16.6 0 100 0 600 i
> > > >
> > > > > *> 20.20.20.0/24 172.16.20.10 0 0 200
> > > > i
> > > > >
> > > > > sw2#sh ip bgp | beg Network
> > > > > Network Next Hop Metric LocPrf Weight Path
> > > > > *> 6.6.6.0/24 172.16.20.2 0 100
> > > > 600 i
> > > > > *> 20.20.20.0/24 0.0.0.0 0 32768 i
> > > > >
> > > > > R1#sh run | beg router ospf|route-map
> > > > > router ospf 1
> > > > > router-id 172.16.101.1
> > > > > redistribute bgp 100 subnets route-map BGPtoOSPF
> > > > > !
> > > > > router bgp 100
> > > > > synchronization
> > > > > bgp log-neighbor-changes
> > > > > neighbor AS100 peer-group
> > > > > neighbor AS100 remote-as 100
> > > > > neighbor AS100 update-source Loopback101
> > > > > neighbor AS100 route-reflector-client
> > > > > neighbor 172.16.16.6 remote-as 600
> > > > > neighbor 172.16.102.1 peer-group AS100
> > > > > neighbor 172.16.103.1 peer-group AS100
> > > > > no auto-summary
> > > > > !
> > > > > !
> > > > > ip prefix-list BGP-Routes seq 5 permit 6.6.6.0/24
> > > > > !
> > > > > route-map BGPtoOSPF permit 10
> > > > > match ip address prefix-list BGP-Routes
> > > > > !
> > > > >
> > > > > R1#sh ip bgp | beg Network
> > > > > Network Next Hop Metric LocPrf Weight Path
> > > > > r>i5.5.5.0/24 172.16.35.5 0 100 0 500 i
> > > >
> > > > > *> 6.6.6.0/24 172.16.16.6 0 0 600 i
> > > > > r>i20.20.20.0/24 172.16.20.10 0 100 0 200
> > > > i
> > > > >
> > > > > R6#sh ip bgp | beg Network
> > > > > Network Next Hop Metric LocPrf Weight Path
> > > > > *> 5.5.5.0/24 172.16.16.1 0 100
> > > > 500 i
> > > > > *> 6.6.6.0/24 0.0.0.0 0 32768 i
> > > > > *> 20.20.20.0/24 172.16.16.1 0 100
> > > > 200 i
> > > > >
> > > > > R3#sh run | beg router ospf|route-map
> > > > > router ospf 1
> > > > > log-adjacency-changes
> > > > > redistribute bgp 100 subnets route-map BGPtoOSPF
> > > > >
> > > > >
> > > > > router bgp 100
> > > > > synchronization
> > > > > bgp log-neighbor-changes
> > > > > neighbor 172.16.35.5 remote-as 500
> > > > > neighbor 172.16.101.1 remote-as 100
> > > > > neighbor 172.16.101.1 update-source Loopback103
> > > > > no auto-summary
> > > > > !
> > > > >
> > > > > !
> > > > > ip prefix-list BGP-Routes seq 5 permit 5.5.5.0/24
> > > > > !
> > > > > route-map BGPtoOSPF permit 10
> > > > > match ip address prefix-list BGP-Routes
> > > > >
> > > > > R3#sh ip bgp | beg Network
> > > > > Network Next Hop Metric LocPrf Weight Path
> > > > > *> 5.5.5.0/24 172.16.35.5 0 0 500 i
> > > > > r>i6.6.6.0/24 172.16.16.6 0 100 0 600 i
> > > >
> > > > > * i20.20.20.0/24 172.16.20.10 0 100 0 200 i
> > > >
> > > > > R3#
> > > > > R5#sh ip bgp | beg Network
> > > > > Network Next Hop Metric LocPrf Weight Path
> > > > > *> 5.5.5.0/24 0.0.0.0 0 32768 i
> > > > > *> 6.6.6.0/24 172.16.35.3 0 100
> > > > 600 i
> > > > >
> > > > > TIA,
> > > > > Mushtaq
> > > > >
> > > > >
> > > >
This archive was generated by hypermail 2.1.4 : Sat Apr 01 2006 - 10:07:38 GMT-3