From: Steve (scromie@cisco.com)
Date: Wed Dec 03 2003 - 17:58:13 GMT-3
Yeah the exercise was supposed to be to show how synchronization works.
So it has the config without synchronization, shows the bgp table and
reouting table and explains, then has me configure synchronization and
shows the difference and epxlains why we need synchronization in an
iBGP. I my bgp and routing table didn't match so I was just wondering if
mine was correct based on the config or if the book was wrong (that
couldn't be). I get the concept but thought maybe I did something wrong.
Thanks,
Steve
-----Original Message-----
From: Bill Lijewski [mailto:bill@eccie.com]
Sent: Wednesday, December 03, 2003 12:43 PM
To: 'Steve'; ccielab@groupstudy.com
Subject: RE: question regarding bgp table output [bcc][faked-from]
Try turning off synchronization on your routers. Internal BGP by
default will look for a match of the BGP route in the IGP table. If it
doesn't find a matching route in the IGP table the BGP route will not be
marked as a best route '>' and will not be sent to any other BGP
neighbors. External BGP does not care about synchronization and will
not perform this check. If there are no restrictions against turning
synchronization off, go ahead and do it.
- Bill Lijewski
CCIE#8642
Network Learning Inc
5 Day R&S CCIE Bootcamp Instructor
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Steve
Sent: Wednesday, December 03, 2003 11:57 AM
To: ccielab@groupstudy.com
Subject: question regarding bgp table output [bcc][faked-from]
Hi, I am working from a book and trying to follow along by creating the
scenarios. I have a problem with this simple BGP set up from what the
book is telling me I should see when doing sh ip bgp and what I actually
do see. Here's the topology etc. (I hope it come out looking right). Any
ideas?
Thanks,
Steve
AS100 | AS200
| AS300
|-----(R5).2---------.1(R3).1-------.2(R2).2---------.1(R4).1---------.2
(R6)------|
| |
| 192.1.2.0/24 131.2.2.0/24 131.2.1.0/24
192.1.1.0/24 131.3.1.1/16 |
131.1.1.1/16
R5 BGP Config
router bgp 100
bgp log-neighbor-changes
network 131.1.0.0
neighbor 192.1.2.1 remote-as 200
R3 BGP config
router bgp 200
bgp log-neighbor-changes
neighbor 131.2.1.1 remote-as 200
neighbor 131.2.2.2 remote-as 200
neighbor 192.1.2.2 remote-as 100
no auto-summary
R2 BGP config
router bgp 200
bgp log-neighbor-changes
network 131.2.1.0 mask 255.255.255.0
network 131.2.2.0 mask 255.255.225.0
neighbor 131.2.1.1 remote-as 200
neighbor 131.2.2.1 remote-as 200
R4 BGP config
router bgp 200
bgp log-neighbor-changes
neighbor 131.2.1.2 remote-as 200
neighbor 131.2.2.1 remote-as 200
neighbor 192.1.1.2 remote-as 300
R6 BGP config
router bgp 300
bgp log-neighbor-changes
network 131.3.0.0
neighbor 192.1.1.1 remote-as 200
The book says I should see this in the BGP table on R3.
Rack3R3#sh ip bgp
BGP table version is 2, local router ID is 192.1.2.1
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
*> 131.1.0.0 192.1.2.2 0 0 100 i
*> 131.2.0.0 0.0.0.0 0 32768 i
* i131.2.1.0/24 131.2.2.2 0 100 0 i
*>i131.2.2.0/24 131.2.2.2 0 100 0 I
Rack3R3#
Instead I see this.
Rack3R3#sh ip bgp
BGP table version is 2, local router ID is 192.1.2.1
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
*> 131.1.0.0 192.1.2.2 0 0 100 i
* i131.2.1.0/24 131.2.2.2 0 100 0 i
Rack3R3#
Did I do something wrong? I'm running IOS 12.2(16)
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