Re: BGP weight

not next-hop ip address but the AS number of 200 being sent back to R2, see
output and debug below:

R1#sh ip bgp neighbors 10.1.12.2 advertised-routes
BGP table version is 5, local router ID is 10.1.14.1
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*> 4.0.0.0 10.1.12.2 50000 200 300 400 i

Total number of prefixes 1

R2#debug ip bgp updates
BGP updates debugging is on for address family: IPv4 Unicast
R2#
*Mar 1 00:38:27.791: %BGP-5-ADJCHANGE: neighbor 10.1.12.1 Down Peer closed
the session
*Mar 1 00:38:38.199: %BGP-5-ADJCHANGE: neighbor 10.1.12.1 Up
*Mar 1 00:38:38.203: BGP(0): 10.1.12.1 send UPDATE (format) 4.0.0.0/8, next
10.1.12.2, metric 0, path 300 400
*Mar 1 00:38:38.307: BGP(0): updgrp 1 - 10.1.12.1 updates replicated for
neighbors:
*Mar 1 00:38:59.443: BGP(0): 10.1.12.1 rcv UPDATE w/ attr: nexthop
10.1.12.1, origin i, originator 0.0.0.0, path 100 200 300 400, community ,
extended community
*Mar 1 00:38:59.447: BGP(0): 10.1.12.1 rcv UPDATE about 4.0.0.0/8 -- DENIED
due to: AS-PATH contains our own AS;

--
Garry L. Baker
"There is no 'patch' for stupidity." - www.sqlsecurity.com
On Fri, Nov 19, 2010 at 2:24 PM, garry baker <baker.garry_at_gmail.com> wrote:
> what does the command 'sh ip bgp neighbors 10.1.12.2 advertised-routes'
> show?
>
> wouldnt it be showing that the R2 address as the next-hop now from R1,
> which would not be a legit route for R2 to put into its bgp table right?
>
> i will throw this up in a lab when i get a minute...
>
>
> --
> Garry L. Baker
>
> "There is no 'patch' for stupidity." - www.sqlsecurity.com
>
>
>
> On Fri, Nov 19, 2010 at 1:30 PM, Jack Router <pan.router_at_gmail.com> wrote:
>
>> I have a question about BGP weight and how it affects routing on other
>> routers. Here is an example:
>>
>> AS100          AS200
>> R1-------------R2
>> |              |
>> |              |
>> |              |
>> R4-------------R3
>> AS400          AS300
>>
>> Router R4 advertises network 4.0.0.0
>> Rip runs on all routers and advertises links between routers.
>>
>> R2 sees two paths to 4.0.0.0 :
>>
>>  Network          Next Hop            Metric LocPrf Weight Path
>> *  4.0.0.0          10.1.12.1                              0 100 400 i
>> *>                  10.1.23.3                              0 300 400 i
>>
>> Now, on router R1 I define weight of 50000 for all routes coming from
>> AS200:
>> # neighbor 10.1.12.2 weight 50000
>>
>> R2 sees now only one route to 4.0.0.0:
>>   Network          Next Hop            Metric LocPrf Weight Path
>> *> 4.0.0.0          10.1.23.3                              0 300 400 i
>>
>> R2 removed path via R1 which is good thing because this would create a
>> loop.
>> My question is:
>> How R2 knows not to use R1 anymore ?
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
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