From: kevin gannon (kevin@gannons.net)
Date: Tue Oct 11 2005 - 15:07:44 GMT-3
In case you have trouble sleeping you can also look into the use
of automatic-tags when doing OSPF to BGP redistribution see
section 4. of the following RFC:
http://www.faqs.org/rfcs/rfc1364.html
Regards
Kevin
On 10/11/05, Andrew Lissitz (alissitz) <alissitz@cisco.com> wrote:
>
> Hello Luis and group,
>
> Luis; I added your request to this email thread so as to keep this
> thread in sync. You asked for the show ip bgp output
10.131.96.0<http://10.131.96.0>.
> Bob
> mentioned that this was normal, is this what you see as well?
>
> If anyone has any comments to my last email, I would greatly appreciate
> it. Kindest regards,
>
> PE1#sh ip bgp 10.131.96.0 <http://10.131.96.0>
> BGP routing table entry for 10.131.96.0/24 <http://10.131.96.0/24>,
> version 17
> Paths: (2 available, best #2)
> Not advertised to any peer
> 200
> 10.131.63.226 <http://10.131.63.226> (metric 116) from
10.131.63.255<http://10.131.63.255>(
> 10.131.63.255 <http://10.131.63.255>)
> Origin IGP, metric 0, localpref 100, valid, internal
> Originator: 10.131.63.251 <http://10.131.63.251>, Cluster list:
> 10.131.63.255 <http://10.131.63.255>
> 200
> 10.131.31.242 <http://10.131.31.242> (metric 106) from
10.131.31.255<http://10.131.31.255>(
> 10.131.31.255 <http://10.131.31.255>)
> Origin IGP, metric 0, localpref 100, valid, internal, best
> Originator: 10.131.31.251 <http://10.131.31.251>, Cluster list:
> 10.131.31.255 <http://10.131.31.255>
>
> PE1#sho ver
> Cisco Internetwork Operating System Software
> IOS (tm) 3600 Software (C3640-P-M), Version 12.0(25)S, EARLY DEPLOYMENT
> RELEASE SOFTWARE (fc1)
>
>
>
> ________________________________
>
> From: Andrew Lissitz (alissitz)
> Sent: Tuesday, October 11, 2005 11:06 AM
> To: 'Bob Sinclair'; C&S GroupStudy; Cisco certification
> Subject: RE: BGP - Tags
>
>
>
> You rock Bob! I guess I never noticed this in the past ... sometimes I
> need to smell the roses. Does anyone know if this was always the case?
>
>
>
> With this info now... can we do clever tricks with filtering just as if
> we had set the tags ourselves? Sorry if this should be self explanatory
> .... it seems convenient to have these tags put on auto-magically...
>
>
>
>
> ________________________________
>
> From: Bob Sinclair [mailto:bob@bobsinclair.net]
> Sent: Tuesday, October 11, 2005 10:58 AM
> To: Andrew Lissitz (alissitz); C&S GroupStudy; Cisco certification
> Subject: Re: BGP - Tags
>
>
> Andrew,
>
> This does appear to be normal behavior. I also see the AS number from
> which this AS learned the prefix as a TAG.
>
> HTH,
>
> Bob Sinclair
> CCIE #10427, CCSI 30427, CISSP
> www.netmasterclass.net <http://www.netmasterclass.net>
>
>
> ----- Original Message -----
> From: Andrew Lissitz (alissitz) <mailto:alissitz@cisco.com>
> To: C&S GroupStudy <mailto:comserv@groupstudy.com> ; Cisco
> certification <mailto:ccielab@groupstudy.com>
> Sent: Tuesday, October 11, 2005 10:00 AM
> Subject: BGP - Tags
>
> Hello Folk,
>
> In a lab I was doing I, there were multiple BGP AS#s. All the
> BGP
> routers were speaking to each other. There were no problems
> with
> routing or anything ... my question is related to some show
> commands I
> saw. Here goes:
>
> PE1#show ip route 10.131.96.0 <http://10.131.96.0>
> Routing entry for 10.131.96.0/24 <http://10.131.96.0/24>
> Known via "bgp 100", distance 200, metric 0
> Tag 200, type internal
> Last update from 10.131.31.242 <http://10.131.31.242> 4d22h ago
> Routing Descriptor Blocks:
> * 10.131.31.242 <http://10.131.31.242>, from
10.131.31.255<http://10.131.31.255>,
> 4d22h ago
> Route metric is 0, traffic share count is 1
> AS Hops 1, BGP network version 0
> Route tag 200
>
> @ the bottom of this you will see the tag 200. This was learned
> from a
> bgp AS # 200. There was no tagging set (please do not ask for
> configs)
> ... This is a MPLS lab / network ... I would not think that this
> would
> make a difference ...
>
> Is this normal... BGP 'auto tagging' of routes learned from
> different AS
> numbers?
>
> Kindest regards,
>
> Andrew
>
>
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