[e2e] Traffic Burstiness Survey

[Anoop Ghanwani]

On Sun, Sep 9, 2012 at 3:39 PM, Craig Partridge <craig at aland.bbn.com> wrote:
>
> I'll make a quick answer in the hopes that someone on the list will provide
> a better one.
>
>> 1) =91Bursty=92 is a word with no agreed meaning. How do you define a burst=
>> y
>> traffic?
>
> I don't know of a widely agreed upon definition.  Generally when people say
> "bursty" traffic they mean non-isochronous traffic -- namely traffic where
> transmissions are not evenly spaced.

I agree with this definition.  Traffic gets to be bursty because of
the "on/off" nature of sources.

>> 2) If you are involved with a data center, is your data center traffic
>> bursty?
>>     -- If yes,
>>         -- Do you think that it will be useful to supress the burstiness in
>> your traffic? (For example by pacing the traffic into shorter bursts)
>>     -- If no:
>>         -- Are you already supressing the burstiness? How?
>>          -- Would you anticipate the traffic becoming burstier in the
>> future?

While I'm not a data center operator, I think I can safely
say that most would categorize their traffic as bursty.
Do they regard it as a problem?  Yes and no.  Yes, because
it impacts the amount of buffering needed in devices.
No because it can largely be solved by overprovisioning
the network and bandwidth is cheap.  Avoiding/mitigating
bursts typically involves shaping and that is expensive and
introduces additional latency.

In general, there are many data center applications --
storage, compute (e.g. hadoop, map reduce), etc. -- and
the traffic patterns for each of those would have to be analyzed
separately.

Anoop