From: Michel Gaspard (mgaspard@xxxxxxxxx)
Date: Tue Apr 03 2001 - 10:12:09 GMT-3
Alan,
I just worked out a BGP config with local-AS and no-export communities.
Basically, it seems to work as expected. Here is my setup:
R1 (AS200, confed 1010)
|
|
R2 (AS200, confed 1000)------R2 (AS200, confed 1000)
|
|
R3 (AS 100)
|
|
R4 (AS300)
1) When I inject routes in BGP process in R1, and tag them with Local-AS OR no-
export
=> I can see them in R2, but not int R3 nor R4
R2#sh ip bgp 33.33.33.0
BGP routing table entry for 33.33.33.0/24, version 5
Paths: (2 available, best #2, not advertised outside local AS)
Not advertised to any peer
(1010)
154.10.5.5 (metric 1563) from 154.10.5.5 (154.10.5.5)
Origin IGP, metric 0, localpref 100, valid, confed-external, ref 2
Community: local-AS <<< community is transferred
(1010)
154.10.5.5 (metric 1563) from 154.10.4.4 (154.10.4.4)
Origin IGP, metric 0, localpref 100, valid, internal, best, ref 2
Community: local-AS
There were no update from R2 to R3, following the community property.
2) When I inject a route into R2, and tag it outgoing (route-map out) with comm
unity "no-export", R3 sees it, but do not export it to R4, as expected.
3) When I inject a route into R2, and tag it outgoing (route-map out) with comm
unity "local-AS", and the same happens: visible in R3, but not in R4.
R3#sh ip bgp 21.21.21.0
BGP routing table entry for 21.21.21.0/24, version 17
Paths: (1 available, best #1, not advertised outside local AS)
200
154.10.3.3 (metric 1563) from 154.10.3.3
Origin IGP, localpref 100, valid, external, best
Community: local-AS
So for me "local-AS" and "no-export" are similar. Anybody has another idea?
One important point was that I had to put the "neighbour send-community" everyw
here, even INSIDE the confederation, otherwise the community was stripped off.
If you still see that problem, check the community at the different routers, an
d make sure it is present (sh ip bgp <IP address>)
Regards,
Michel
> From nobody@groupstudy.com Wed Mar 28 18:36:37 2001
> Date: Wed, 28 Mar 2001 10:03:49 -0600
> From: Alan Basinger <abasinge@swbell.net>
> Subject: BGP no-export or local-as
> To: ccielab@groupstudy.com
> Importance: Normal
> Sender: nobody@groupstudy.com
> Reply-To: Alan Basinger <abasinge@swbell.net>
> X-Status:
> X-Keywords:
> X-UID: 1263
>
> While working on a BGP lab last night to get ready for my upcoming lab on
> 4/2-3. I wanted to increase my speed and understanding of non-transit AS
> commands in a confederation environment with route-reflectors other than
> using AS-PATH manipulation. While looking up the topic on the CD (also have
> been using it for last week and a half to get better instead of books) I
> noticed this statement. Which one is used in conjunction with Confederations
> and which isn't?
>
> no-export---Do not advertise this route to EBGP peers.
>
> local-as---Send this route to peers in other sub-autonomous systems within
> the local confederation. Do not advertise this route to an external system.
>
>
> So I created a route map with the local-as attrib and noted that internal to
> my confederation I was not seeing the routes and external to the
> confederation I was seeing all the routes???
>
> This being the opposite of what I expected I changed the route-map to
> no-export and guess what?? I could see all the routes inside my
> confederation and none of them external to the confederation.
> Now this makes me wonder about the answer above cut and pasted from the doc
> CD???
>
> It seems as if the answers above are exactly opposite of what the real
> answer is as least in my lab configs.
>
> Alan
>
> **NOTE** All LAB SWAP messages should now be sent to the
> LAB SWAP Message board on groupstudy.com.
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