Re: [nsp] Oversubscription....What are the ratios you are seeing...

From: Rodney van den Oever (RvdOever@chello.nl)
Date: Wed Feb 21 2001 - 10:44:45 EST


Oversubscription....What are the ratios you are seeing...> What sort of
oversubscription ratios are you using for DSL?
> Is there any rule of thumb being applied or is it just how much
> oversubscription can the clients tolerate?

Internal or external traffic? Do you have local content like caching, news
etc.? In my current situation we use 4:1 (at least on the DSLAM level).

Most DSL operators appear to operate in the wholesale model and carry
PPP-sessions across an ATM-backbone towards one or more ISP's. Traffic is
therefore always carried between CPE and PPP-termination endpoint, with no
traffic between POPs. This means you cannot really overbook again for
traffic across the backbone.

This model also makes it difficult (read impossible) to distribute content
(caching, new) closer to the users.

100 users / T1 has been mentioned before as a general guideline for external
traffic. But in my view this is way too low. Something like this seems much
more reasonable:

access-speed (say 1Mbps) x 50% (online-concurrency) x 15% (traffic) =
75kbps.

--
Rodney van den Oever / KeyID 0x0A6CCE53
'OIR - On Insertion Reload'



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:29 EDT