From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Sat Jun 01 2002 - 22:09:47 GMT-3
Joe,
That seems to be a real cool feature.
However its implemented in 12.2,and I was actually after some route-map
match/set behaviour to acheive conditional advertisement.
I havent read thru completely (nor have I labbed it up) about this inject
feature, but I suspect it will be the same as advertise-map & non-exist map
feature.
rgds
Nick
-----Original Message-----
From: Joe Jia <ellenjjl@rogers.com>
To: Nigel Taylor <nigel_taylor@hotmail.com>; ccielab@groupstudy.com
<ccielab@groupstudy.com>
Date: Sunday, 2 June 2002 10:43
Subject: Re: BGP conditional Advertisement
>Hi,
>
>This link maybe useful?
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/12
2
>t/122t4/ftbgpri.htm
>
>
>----- Original Message -----
>From: "Nigel Taylor" <nigel_taylor@hotmail.com>
>To: <ccielab@groupstudy.com>
>Sent: Saturday, June 01, 2002 6:44 PM
>Subject: Re: BGP conditional Advertisement
>
>
>> Nick,
>> I understand what it is you're trying to accomplish by trying
to
>> find another way to perform BGP conditional route advertising.
>> However, as Howard points out the question would be why? I've looked at
>the
>> scenario you've posted and based on the information
>> you provided, I don't see how we can get the BGP process in RtrC to
>> conditionally source the Y/24 network, without some type of
>> tracking of routes in the BGP table. You mentioned the goal is to
>> accomplish this without specifically using the
>> "advertise-map & non-exist-map" neighbor command. The only other options
>> left would be using filter-list, distribute-list, and route-maps
>> which would be static configurations.
>>
>> I did some thinking and it came to me that maybe the only other way I
>could
>> think of to accomplish this would be to, identify the X/24 route being
>> received from RtrA at RtrC using a route-map and setting a community
>string
>> on the X/24 route. Then under the bgp process of RtrC you could
>> use the "network" command with a "route-map" to set another community
>string
>> for the Y/24 route. Lastly you could set and outbound route-map
>> to RtrB(on RtrC) using the 'no-advertise" attribute to filter the Y/24
>route
>> based on if the X/24(community) route is present or not.
>>
>> Nigel
>>
>>
>> ----- Original Message -----
>> From: "Howard C. Berkowitz" <hcb@gettcomm.com>
>> To: <ccielab@groupstudy.com>
>> Sent: Saturday, June 01, 2002 2:54 PM
>> Subject: Re: BGP conditional Advertisement
>>
>>
>> > At 7:08 PM +1000 6/1/02, Nick Shah wrote:
>> > >Nigel,
>> > >
>> > >All routers are running in different AS's
>> > >
>> > >No IGP's running between all of the 3 routers.
>> > >
>> > >X/24 is being originated from RtrA
>> > >y/24 is to be *conditionally * originated by RtrC (if RtrC stops
>> receiving
>> > >X/24 from RtrA)
>> >
>> > I, too, don't quite have enough detail to give a definitive answer,
>> > particularly as to where y/24 is and how router C knows about it.
>> >
>> > What is the address relationship between x and y? What problem are
>> > you trying to solve? This doesn't seem a plausible backup scenario,
>> > unless y is an alternate address that will be tried in recovery by a
>> > host connected to rtrB.
>> >
>> > Approaches that might be considered include making the next hop in C
>> > for y primarily dependent on the reachability of a next hop in A.
>> > Another approach might be to use outbound route filtering in B to C,
>> > in which B tells C not to advertise y as long as it is receiving x
>> > originated by A.
>> >
>> > >
>> > >thanks
>> > >Nick
>> > >-----Original Message-----
>> > >From: Nigel Taylor <nigel_taylor@hotmail.com>
>> > >To: ccielab@groupstudy.com <ccielab@groupstudy.com>
>> > >Date: Saturday, 1 June 2002 3:43
>> > >Subject: Re: BGP conditional Advertisement
>> > >
>> > >
>> > >>Nick,
>> > >> I have a couple of questions?
>> > >>
>> > >>1. What AS's are the 3 routers in? could you be more specific.
>> > >>2. The X and Y routes where do they originate? both from RtrA, X
from
>> > >RtrA,
>> > >>Y from RtrC?
>> > >>3. Are there any IGPs running between all the routers.
>> > >>
>> > >>Nigel
>> > >>
>> > >>----- Original Message -----
>> > >>From: "Nick Shah" <nshah@connect.com.au>
>> > >>To: <ccielab@groupstudy.com>
>> > >>Sent: Friday, May 31, 2002 11:11 PM
>> > >>Subject: BGP conditional Advertisement
>> > >>
>> > >>
>> > >>> Guys,
>> > >>>
>> > >>> I am trying to achieve a behaviour similar to BGP conditional
>> > >>advertisement
>> > >>> *without* using non-exist-map and/or advertise-map. Basically ...
>> > >>>
>> > >>> RtrA ------- RtrC-----------RtrB
>> > >>>
>> > >>> RtrA advertises route X/24 to RtrC under normal circumstances,
when
>> RtrC
>> > >>is
>> > >>> receiving X/24 from RtrA it suppresses the advertisement of Y/24
>> (doesnt
>> > >>> advertise) to RtrB.
>> > >>> But if RtrA stops sending prefix X/24 to RtrC, RtrC starts sending
>> Y/24
>> > >to
>> > >>> RtrB.
>> > >>>
>> > >>> All this to be done *without* using advertise-map & non-exist-map
>> > >>>
>> > >>> Ideas..
>> > >>> Nick
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