Hi Lorenzo, Thank you so much for your prompt reply and the suggested setup. I think the setup should be adequate for our experiments, except that for a given prefix we generally need to advertise the prepended routes to some (e.g., 1) upstream ASs and unprepended routes to others. Can the setup that you suggested enable us to do that (through an access list, or different peer sessions, or community but which is not supported by the announcer you provided, or peer to more than one RRC)? In the meantime, we will set up a BGP speaker here with the announcer. But if the announcer is not adequate for announcing prefixes with different prepending lengths to different upstream ASs, we may need to use some software routers. We are planning to submit a paper to the IMC conf, and the deadline is late May. If you are interested, you are welcome to join our work. Best regards, Samantha http://www.comp.polyu.edu.hk/~cssmlo/ cssmlo@comp.polyu.edu.hk Phone: +852-27764901 Fax: +852-27740842 Lorenzo Colitti said the following on 3/13/2006 11:19 PM:
Samantha Lo wrote:
Dear Lorenzo,
Thank you for your kind consideration. We are looking forward to your favorable reply.
Hi Samantha,
we have looked into this and we have determined that we do not have the resources to do what you have requested. However, we would like to suggest an alternative.
We can set up an IBGP peering session between a BGP speaker of your choice and one of our RRCs (RRC07). You would thus be inside AS12654. You could then announce the two prefixes 84.205.73.0/24 and 84.205.89.0/24, which are RIS beacons, with AS-paths of the form "12654 <AS path of your choice> i". These paths will be announced to the transit peers of RRC07.
Note that if you use your own AS in the AS-path, it might get filtered out since our peers might filter on origin AS. However, you could prepend AS 12654 multiple times.
If you do not have software to generate IBGP announcements, you can use the "announcer" tool [1] to do this. I wrote this tool and have used it successfully for other research work [2]. Combined with a cron script, it should be sufficient for your needs. (If it's not, let me know what it's missing!).
If you think this would be useful to you, please provide us with a few lines describing your experiment and what kind of paths you will announce so that we can inform our upstream peers. If our peers agree, we can then discuss the dates on which we will set up the peering and on which you will perform your experiments.
Regards, Lorenzo
[1] http://www.dia.uniroma3.it/~compunet/bgp-probing/announcer/ [2] Colitti et al., "Investigating prefix propagation through active BGP probing", to appear in Proceedings of IEEE ISCC 2006.