Re: POP Quiz - Answers

From: Michael Kilpatrick (mjkilpat@xxxxxxxxx)
Date: Fri May 17 2002 - 14:44:39 GMT-3


   
I am having a problem getting this config to work...
(1) AS-path information is not being maintained
(2) even with table-map statement, AS-path or ORIGIN code not being
maintained
(3) cannot see tag information on router_B with sh ip route x.x.x.x (Doyle
Vol 2, pg 258)
(4) transit links are also showing up in BGP tables even though I have
configured to MATCH EXTERNAL
Wondering if problem is same as what Doyle references in Vol 2, pg 260...
"When the network command is used, the BGP route is considered locally
originated and therefore does not inherit any of the attributes, including
tags, of the IGP route. However, better chance that I am missing something
in my config... pls advise. Thanks Mike

router_A_#sh run

interface Loopback0
 ip address 1.1.1.1 255.255.255.255

interface Ethernet0
 ip address 192.168.1.1 255.255.255.0
 media-type 10BaseT

 router ospf 110
 log-adjacency-changes
 redistribute bgp 1 subnets
 network 192.168.1.0 0.0.0.255 area 0

router bgp 1
 no synchronization
 table-map send-tag
 bgp log-neighbor-changes
 network 1.1.1.1 mask 255.255.255.255
 redistribute ospf 110 match external 1 external 2 route-map get-tag
 no auto-summary

ip as-path access-list 1 permit .*
route-map get-tag permit 10
 set as-path tag
route-map send-tag permit 10
 match as-path 1
 set automatic-tag

router_A_#sh ip bgp
BGP table version is 5, local router ID is 1.1.1.1
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
*> 1.1.1.1/32 0.0.0.0 0 32768 i
*> 3.3.3.3/32 192.168.1.2 1 32768 ?
*> 172.16.1.0/24 192.168.1.2 20 32768 ?
*> 192.168.1.0 0.0.0.0 0 32768 ?

router_B_>sh ip route 1.1.1.1
Routing entry for 1.1.1.1/32
  Known via "ospf 110", distance 110, metric 1, type extern 2, forward
metric 10
  Last update from 192.168.1.1 on Vlan4, 00:50:28 ago
  Routing Descriptor Blocks:
  * 192.168.1.1, from 1.1.1.1, 00:50:28 ago, via Vlan4
      Route metric is 1, traffic share count is 1

router_C_#sh run

interface Loopback0
 ip address 3.3.3.3 255.255.255.255
!
interface Ethernet0
 ip address 172.16.1.2 255.255.255.0
 media-type 10BaseT
!
router ospf 110
 log-adjacency-changes
 redistribute bgp 2 subnets
 network 172.16.1.0 0.0.0.255 area 0
!
router bgp 2
 table-map send-tag
 bgp log-neighbor-changes
 network 3.3.3.3 mask 255.255.255.255
 redistribute ospf 110 match external 1 external 2 route-map get-tag
 no auto-summary
!
ip as-path access-list 1 permit .*
route-map get-tag permit 10
 set as-path tag
route-map send-tag permit 10
 match as-path 1
 set automatic-tag

router_C_#sh ip bgp
BGP table version is 5, local router ID is 3.3.3.3
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
*> 1.1.1.1/32 172.16.1.1 1 32768 ?
*> 3.3.3.3/32 0.0.0.0 0 32768 i
*> 172.16.1.0/24 0.0.0.0 0 32768 ?
*> 192.168.1.0 172.16.1.1 20 32768 ?

----- Original Message -----
From: "Jason Sinclair" <sinclairj@powertel.com.au>
To: "Jason Sinclair" <sinclairj@powertel.com.au>; <ccielab@groupstudy.com>
Sent: Wednesday, May 15, 2002 3:21 AM
Subject: RE: POP Quiz - Answers

> All,
> Guys,
>
> For pop quiz 1 I have the following configs. I have not labbed them due to
> time constraints, however I believe they are correct. If you see any
> mistakes please advise.
>
> Configs are:
>
> RtrA
> Int lo0
> Ip address 1.1.1.1 255.255.255.255
>
> Int s0
> Ip address 192.168.1.1 255.255.255.0
>
> Router ospf 100
> Network 192.168.1.0 0.0.0.255 area0
> Redistribute bgp 100 subnets
>
> Router bgp 100
> Network 1.1.1.1 mask 255.255.255.255
> Redistribute ospf 100 route-map tags
> No auto-summary
> No synchronization
>
> Route-map tags permit 10
> Set as-path tag
>
> Rtrb
> Int s0
> Ip address 192.168.1.2 255.255.255.0
> Clock rate 64000
>
> Int s1
> Ip address 172.16.1.1 255.255.255.0
> Clock rate 64000
>
> Router ospf 100
> Network 192.168.1.0 0.0.0.255 area 0
> Network 172.16.1.0 0.0.0.255 area 0
>
> Rtrc
> Int lo0
> Ip address 3.3.3.3 255.255.255.255
>
> Int s0
> Ip address 172.16.1.2 255.255.255.0
>
> Router ospf 100
> Network 172.16.1.0 0.0.0.255 area0
> Redistribute bgp 100 subnets
>
> Router bgp 100
> Redistribute ospf 100 route-map tags
> Network 3.3.3.3 mask 255.255.255.255
> No auto-summary
> No synchronization
>
> Route-map tags permit 10
> Set as-path tag
>
> Cheers,
>
> Jason Sinclair CCIE #9100
> Manager, Network Control Centre
> POWERTEL
> Ground Level, 55 Clarence Street,
> SYDNEY NSW 2000
> AUSTRALIA
> office: + 61 2 8264 3820
> mobile: + 61 416 105 858
> * sinclairj@powertel.com.au
>
>
>
>
> -----Original Message-----
> From: Jason Sinclair [mailto:sinclairj@powertel.com.au]
> Sent: Wednesday, 8 May 2002 13:32
> To: 'ccielab@groupstudy.com'
> Subject: POP Quiz
>
> All,
>
> I am proposing to regularly post little scenarios to this
> forum. If you see
> any benefit in this, the first is below:
>
> Quick Scenario 1:
>
> A quick scenario - should take 10 minutes to achieve.
> Topology is:
>
>
> RtrA-----rtrB-------rtrC
>
> Rules:
> 1. You can run BGP on rtrA and rtrC, but NOT rtrB.
> 2. Any IGP can be run on rtrA, rtrB, rtrC.
> 3. Create a loopback on rtrA and rtrC and ensure that
> the opposite
> route to the loopback is visible to the remote router via
> BGP.
> 4. You cannot peer rtrA and rtrC with respect to BGP
> 5. The origin code for your route must be the same as
> the original
> origin code when the route was injected into BGP
> 6. 10 minutes to complete
>
> I will post answers in 5 days time.
>
> Cheers,
>
> Jason Sinclair CCIE #9100
> Manager, Network Control Centre
> POWERTEL
> Ground Level, 55 Clarence Street,
> SYDNEY NSW 2000
> AUSTRALIA
> office: + 61 2 8264 3820
> mobile: + 61 416 105 858
> * sinclairj@powertel.com.au
>
>
>
>
>
>
> **********************************************************************
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>
>
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