From: san (san.study@gmail.com)
Date: Fri Mar 10 2006 - 03:51:23 GMT-3
Chris,
Basic question, based on your explanation. I have pasted sh commands.
By saying Router-id...I think you are trying to mean "advertising
router field". correct ?
Also, How would i change the advertising router or Router-id ? Any
method or commands ?
Rack1R2#sh ip ospf database
OSPF Router with ID (12.12.12.12) (Process ID 12)
Router Link States (Area 12)
Link ID ADV Router Age Seq# Checksum Link count
11.11.11.11 11.11.11.11 879 0x800000E0 0x00E1FC 1
12.12.12.12 12.12.12.12 1108 0x800000DD 0x00C314 1
13.13.13.13 13.13.13.13 868 0x800000DF 0x005848 2
Net Link States (Area 12)
Link ID ADV Router Age Seq# Checksum
10.1.1.1 11.11.11.11 879 0x800000DC 0x00FCC7
10.1.2.2 12.12.12.12 1108 0x800000DA 0x00EFCC
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
10.1.0.0 11.11.11.11 1011 0x80000001 0x000E5B 0
111.111.111.111 11.11.11.11 1012 0x80000001 0x009620 0
Rack1R2#
Rack1R2#
Rack1R2#sh ip ospf data
Rack1R2#sh ip ospf database external
OSPF Router with ID (12.12.12.12) (Process ID 12)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 1084
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 10.1.0.0 (External Network Number )
Advertising Router: 11.11.11.11
LS Seq Number: 80000001
Checksum: 0xE5B
Length: 36
Network Mask: /16
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
Routing Bit Set on this LSA
LS age: 1085
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 111.111.111.111 (External Network Number )
Advertising Router: 11.11.11.11
LS Seq Number: 80000001
Checksum: 0x9620
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
Thanks
SAN
On 3/9/06, Chris Lewis <chrlewiscsco@gmail.com> wrote:
> 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
> > > > > >
> > > > > >
> > > > >
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