The Qos PipeDream [Was: RE: Two Tiered Internet]

Sun Dec 18 19:28:31 UTC 2005

Chris Woodfield wrote:

> 
> One thing to note here is that while VoIP flows are low volume on a  
> bits-per-second basis, they push substantially more packets per  kilobit 
> than other traffic types - as much as 50pps per 82Kbps flow.  And I have 
> seen cases of older line cards approaching their pps  limits when 
> handling large numbers of VoIP flows even though there's  plenty of 
> throughput headroom. That's not something LLQ or priority  queueing are 
> going to be able to help you mitigate at all.
> 
> -C

In that vein, and not quite on this topic, it would be real nice if voip 
applications made an effort to stop abusing networks with unneccessarily 
large pps.

Something about intelligent edges? The payload length of voip 
applications often has a lot to do with rtt. Adapting payload length to 
the actuall average rtt could have a positive effect on pps throughput.