[e2e] Why Buffering?

Arun Vishwanath arunv at ee.unsw.edu.au
Sun Jun 21 02:58:07 PDT 2009

Hello Everyone,

       We recently published a survey paper on the topic of router 
buffer sizing titled "Perspectives on Router Buffer Sizing: Recent 
Results and Open Problems". This appeared in the ACM SIGCOMM Computer 
Communication Review Editorial Zone, vol. 39, no. 2, April 2009.

       This is just for your kind information.


Detlef Bosau wrote:
> David P. Reed wrote:
>> Dave - This is variously known as Little's Theorem or Little's Lemma.  
>> The general pattern  is true for many stochastic arrival processes 
>> into queues.  It precedes Kleinrock, and belongs to queueing theory.
> Little's Theorem can be easily applied in wired networks where a link's 
> capacity is easily expressed as "latency throghput product", often 
> referred to as "latency bandwidth product" which is in fact a bit sloppy.
> The situation becomes a bit more complicated in wireless networks, 
> particularly WWAN, where the preconditions for Little's Theorem may not 
> hold, particularly the service time may not be stationary or stable.
> I sometimes wonder about papers who claim quite impressive "latency 
> bandwidth products" for wireless networks - and actually the authors 
> simply miss the fact that the transportation system is highly occupied 
> by local retransmissions and that we have a relationship between average 
> service, average throughput and the average amount of data  being in 
> flight.
> I even remember a paper which claims latency bandwidth products for GPRS 
> in the range of MBytes IIRC.
> At a first glance, I wondered where this huge amount of data would fit 
> onto the air interface ;-)
> So, we should be extremely careful in applying Little's Theorem on WWAN. 
> As a consequence, we should even reconsider approaches like packet pair, 
> packet train and the like and whether they really hold in WWAN or 
> similar networks with highly volatile line conditions.
> Detlef

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