Re: bgp local preference

That's the only way I could think of this. But you would have to assume the
other router was configured as a confederation already.

He did not state that but I was not sure if it was a challenge or if he
really wanted to know how.

Kind of like the riddle..... you have to make 2 coins that equal 30 cents.
One of them is not a Quarter.

Paul

-- 
Paul Negron
CCIE# 14856 CCSI# 22752
Senior Technical Instructor
> From: Brian Dennis <bdennis_at_ine.com>
> Organization: INE, Inc
> Reply-To: Brian Dennis <bdennis_at_ine.com>
> Date: Mon, 12 Mar 2012 23:07:38 -0700
> To: <ccielab_at_groupstudy.com>
> Subject: Re: bgp local preference
> 
> RFC 4271 (A Border Gateway Protocol 4 (BGP-4)) states in regards to
> local preference that eBGP peers "MUST NOT include this attribute in
> UPDATE messages" but since the logic and terminology used in RFCs is
> confusing to a few people here on the list, let me put this another way
> ;-)  What the RFC is saying is that if you if you try to set the local
> preference to an eBGP peer that it MUST NOT be sent and MUST be ignored
> by the other side of the eBGP peering session if received.  But if you
> read the next sentence in the RFC, you will note that this isn't the
> case with eBGP peers within a confederation.  In your situation below,
> possibly the router in AS 200 is already setup with the confederation
> commands and if so you can just need to complete the confederation
> configuration in AS 100 and finally set the local preference outbound
> from AS 100 to AS 200.
> 
> Here is a simple setup with two routers.  R1 is in AS 100 and R2 is in
> AS 200.  They are eBGP confederation peers.  R1 is advertising
> 1.1.1.1/32 with a local preference of 250 set using a route-map outbound
> to R2.
> 
> **************** R1 ****************
> 
> Rack1R1#show run | section bgp|route-map
> router bgp 100
>   bgp confederation identifier 1000
>   bgp confederation peers 200
>   network 1.1.1.1 mask 255.255.255.255
>   neighbor 10.1.1.2 remote-as 200
>   neighbor 10.1.1.2 route-map SET_LOCAL_PREF out
> route-map SET_LOCAL_PREF permit 10
>   set local-preference 250
> Rack1R1#
> Rack1R1#show bgp ipv4 unicast 1.1.1.1/32
> BGP routing table entry for 1.1.1.1/32, version 3
> Paths: (1 available, best #1, table Default-IP-Routing-Table)
> Flag: 0x820
>    Advertised to update-groups:
>          1
>    Local
>      0.0.0.0 from 0.0.0.0 (1.1.1.1)
>        Origin IGP, metric 0, localpref 100, weight 32768, valid,
> sourced, local, best
> Rack1R1#
> 
> **************** R2 ****************
> 
> Rack1R2#show run | section bgp
> router bgp 200
>   bgp log-neighbor-changes
>   bgp confederation identifier 1000
>   bgp confederation peers 100
>   neighbor 10.1.1.1 remote-as 100
> Rack1R2#
> Rack1R2#show bgp ipv4 unicast 1.1.1.1/32
> BGP routing table entry for 1.1.1.1/32, version 2
> Paths: (1 available, best #1, table default)
>    Not advertised to any peer
>    (100)
>      10.1.1.1 from 10.1.1.1 (1.1.1.1)
>        Origin IGP, metric 0, localpref 250, valid, confed-external, best
> Rack1R2#
> 
> 
> Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice)
> bdennis_at_ine.com
> 
> Internetwork Expert, Inc.
> http://www.INE.com
> 
> On 03/12/2012 09:21 PM, nitin shettigar wrote:
>> BGP AS 100(local-preference 100) has network 1.1.1.1 advertised with 32 bit
>> mask. I want the local preference of the network 1.1.1.1 to be 250 in AS
>> 200(local-preference 100) with out making any changes in AS 200.
>> All's working fine between AS 100 and AS 200.
>> 
>> Please provide me a solution...
>> 
>> Nitin
>> 
>> 
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