I have some questions regarding an IX point. If I go to PacBell and sign the multilateral peering agreement it anyone and everyone can peer with me and I can peer with everyone else. Now if I buy a DS3 UBR port then my cells/packets have to contend with everyone else who is trying to egress out to an upstream provider. If there is contention then my cells can be dropped and my packets are unable to be reconstructed by the router. Does anyone know how this works at the Chicago NAP? Is my PCR for my ATM port set at line speed for DS3 OC3 and OC12. How do they prevent random cell discard at the egress port to upstream providers, is there a graceful discard so that cells are dropped to maximize good "packets". How does Pacbell ensure that there is a level of fairness for packet traffic. I understand that it will be UBR, but if Pacbell is sending only cells to upstream that randomly make it through the egress queues, there is really no way to ensure that ANY packets can get through. All the cells could be partial packet info. Any insight into this would be helpful so that I do not purchase a service that is worthless.
-----BEGIN PGP SIGNED MESSAGE----- At 03:08 PM 1/10/2001 -0500, Robbie Harrell wrote:
Does anyone know how this works at the Chicago NAP? Is my PCR for my ATM port set at line speed for DS3 OC3 and OC12. How do they prevent random cell discard at the egress port to upstream providers, is there a graceful discard so that cells are dropped to maximize good "packets".
All of our peerings at the Chicago NAP contend for access. Discard happens randomly. That is, we assume the Chicago NAP is a UBR service. The Chicago NAP publishes the line rate of each customer. We set our router to queue cells at the appropriate rate (DS-3, OC-3, whatever) for that peer. We also set our ATM switch to do ATM packet discard, of course. In practice this has worked quite well for us. === Bill Nickless http://www.mcs.anl.gov/people/nickless +1 630 252 7390 PGP:0E 0F 16 80 C5 B1 69 52 E1 44 1A A5 0E 1B 74 F7 nickless@mcs.anl.gov -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.8 for non-commercial use <http://www.pgp.com> iQCVAwUBOlzHxqwgm7ipJDXBAQEkoAP/RbNxPa6Qcre9bKHm59dF2wLYSmFVuX7z zWZr2b/j6PyP1MpANTJ5MgVRNwhuM9rRU+UjyeMPHTBR69KqG1jvVNBS4DYhPUR0 lI5h5pv/blyfcp6CXvR1GEUacmo8AQ0pvCSkGYp4MvYNuT+7q4qY6Jbk8XO9h/fU ri/nRwr7mG4= =lE4b -----END PGP SIGNATURE-----
participants (2)
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Bill Nickless -
Robbie Harrell