Mailing List Archive: NANOG: users

Strip AS in BGP peer

Index | Next | Previous | View Threaded

sherwin.ang at gmail

Oct 28, 2009, 7:10 AM

Post #1 of 5 (938 views)
Permalink

Strip AS in BGP peer

Hello Nanog,

am not sure if i should have placed this on the cisco-nsp or the
juniper-nsp but someone may have a direct answer.

well here it goes. we'll soon form a new internet exchange and i
would like to suggest a model in the route-server wherein the
route-server would strip out it's own AS and give the neighbors/peers
the AS's of the members. I have seen this in Any2IX but i have no
idea on how to implement it as if i am the Any2 route-server.

if you could point me to the right direction or reading, i could take
it from there.

-Sherwin

adrian at creative

Oct 28, 2009, 7:19 AM

Post #2 of 5 (930 views)
Permalink

Re: Strip AS in BGP peer [In reply to]

Take a read of the quagga documentation. There's a BGP neighbor option
for stripping out the local AS when speaking eBGP.

Adrian

On Wed, Oct 28, 2009, Sherwin Ang wrote:
> Hello Nanog,
>
> am not sure if i should have placed this on the cisco-nsp or the
> juniper-nsp but someone may have a direct answer.
>
> well here it goes. we'll soon form a new internet exchange and i
> would like to suggest a model in the route-server wherein the
> route-server would strip out it's own AS and give the neighbors/peers
> the AS's of the members. I have seen this in Any2IX but i have no
> idea on how to implement it as if i am the Any2 route-server.
>
> if you could point me to the right direction or reading, i could take
> it from there.

kizmet at kizmet

Oct 28, 2009, 11:01 AM

Post #3 of 5 (895 views)
Permalink

Re: Strip AS in BGP peer [In reply to]

More specifically:
- neighbor *ip or peer-group* attribute-unchanged as-path

Cheers,
Cody

On Wed, 28 Oct 2009 22:19:54 +0800, Adrian Chadd <adrian [at] creative>
wrote:
> Take a read of the quagga documentation. There's a BGP neighbor option
> for stripping out the local AS when speaking eBGP.
>
>
>
> Adrian
>
> On Wed, Oct 28, 2009, Sherwin Ang wrote:
>> Hello Nanog,
>>
>> am not sure if i should have placed this on the cisco-nsp or the
>> juniper-nsp but someone may have a direct answer.
>>
>> well here it goes. we'll soon form a new internet exchange and i
>> would like to suggest a model in the route-server wherein the
>> route-server would strip out it's own AS and give the neighbors/peers
>> the AS's of the members. I have seen this in Any2IX but i have no
>> idea on how to implement it as if i am the Any2 route-server.
>>
>> if you could point me to the right direction or reading, i could take
>> it from there.

arnold at nipper

Oct 28, 2009, 11:51 AM

Post #4 of 5 (917 views)
Permalink

Re: Strip AS in BGP peer [In reply to]

On 28.10.2009 19:01 Cody Appleby wrote

> More specifically:
> - neighbor *ip or peer-group* attribute-unchanged as-path
>

To leave _everything_ unchanged (med and next hop which goes w/o saying
;-)) might even best. Hence go for

neighbor <ip> attribute-unchanged

Of course there are also other implemenations like OpenBGPD and BIRD
(http://bird.network.cz/) which also do support that feature.

You could even do per peer RIB to give each of your customer its own
view. Does work for small to medium sized IXP but has not yet proven to
run for really large IXP.

Best regards,
Arnold
--
Arnold Nipper / nIPper consulting, Sandhausen, Germany
email: arnold [at] nipper phone: +49 6224 9259 299
mobile: +49 172 2650958 fax: +49 6224 9259 333

Attachments:

signature.asc (0.25 KB)

andy at nosignal

Nov 20, 2009, 5:45 PM

Post #5 of 5 (828 views)
Permalink

Re: Strip AS in BGP peer [In reply to]

Sherwin Ang wrote:
> well here it goes. we'll soon form a new internet exchange and i
> would like to suggest a model in the route-server wherein the
> route-server would strip out it's own AS and give the neighbors/peers
> the AS's of the members. I have seen this in Any2IX but i have no
> idea on how to implement it as if i am the Any2 route-server.

Hi, Sherwin

Sorry for the late reply.

We (LONAP, London UK) have deployed our route-servers using BIRD and
OpenBGPd on unix servers, rather than traditional big iron hardware for the
following reasons :

- Availability of the 'stripped asn' feature as you describe.
- Multiple RIBs per BGP instance, so that route-server participants who
filter (on the route-server) can do so without causing shadowing of prefixes.
- Don't need the high-capacity forwarding - the route-servers swap
prefixes, not traffic.

As other posters in this thread have described, it's also possible to do
this with the Quagga software, but the current codebase appears to creak
(and then croak !) with scale, when multiple-ribs are enabled.

This email is pretty brief; the exchange community have been discussing
this and publishing talks on the subject since the beginning of the year,
as our understanding of the problems of running the common open-source so I
can point you to some resources that you may find interesting :

Our decisions and introduction to the LONAP service :
http://www.uknof.org.uk/uknof13/Davidson-LONAP_routeservers.pdf

INEX (Dublin, IE) describe the per-peer RIB problem and Quagga problems :
http://www.ripe.net/ripe/meetings/ripe-58/content/presentations/Hilliard-Why_use_Quagga_for_Route_Servers.pdf

LINX (London, UK) also describe the per-peer RIB problem and explain their
efforts to solve the Quagga problems :
http://www.uknof.org.uk/uknof13/Hughes-IXP_routeservers.pdf

EuroIX route server activity report from October :
http://www.ripe.net/ripe/meetings/ripe-59/presentations/hiliard-euroix-update.pdf
(Situation is more evolved now, but I don't know if more recent slides are
public)

The situation is likely to move quickly by the middle of next year, if
there is interest it sounds like a good operational BOF for N'49.

Andy

Index | Next | Previous | View Threaded

Interested in having your list archived? Contact Gossamer Threads