[LARTC] Using HTB as an ISP "provisioning engine"

[Brian Capouch <brianc@palaver.net>]

I am new to shaping but not to routing; forgive me if this request is 
inappropriate for this list.

I am a very small ISP and would like to use HTB to enforce contractual 
bandwidth limits on my customers.  I am trying to think through one 
aspect of this that is vexing me.  I'm sure it's no great secret that 
many ISPs oversell their bandwidth, and in our case we have a 
combination of accounts that total approximately 2.2Mbs on our feed, 
which is 1.2Mbs. (Concentrating right now on our download stream)

How could something like this be accomodated?  The documentation says 
that the total bandwidth allocations of a set of subclasses should total 
that assigned to the class.

But my understanding is that if I bump up the bandwidth on the primary 
class to a value greater than my actual bandwidth, then I'm going to be 
filling up queues at the upstream ISP and negatively affecting my 
performance.

I'm sure there is something I'm missing, but I've discussed this with a 
couple of fellow network engineers and neither was able to posit how 
such thing might work, although they both said they were sure that it is 
a common scenario.

Thanks.

B.

_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/