avg at exigengroup.com
Sat Nov 16 23:03:18 UTC 2002
On Sat, 16 Nov 2002, Petri Helenius wrote:
> >In any case, TV (of all things) does not have problems with latency or
> >jitter below 10s of seconds. All TV content is pre-packaged.
> Live events and interactive show's are not.
"Live" events are typically delayed by a minute or so to give time to
editors to decide on course of action if something goes wrong with "live"
feed. In any case, nobody cares about another half-minute of delay.
The same pretty much goes for "interactive" shows - which all have
interaction loops of minutes, not sub-second response which is hard to do
over the regular Internet.
> In some cases you start to suffer if your latency goes to
> multiple-seconds range. That's quite rare anyway, >500ms network
> latency is quite rare and add few hundred codec and de-jitter latency
> and you'll find that excessive jitter is your enemy, not the latency
Excessive jitter is easily converted into latency by having bigger buffers
at the receiving end.
So far, the only mass applications which have real need to have low
latency are telephony (including video kind) and on-line gaming. Those
are relatively low-bandwidth, and so don't contribute much to long-haul
Of course, hauling bits over long-distance circuits costs more than doing
the same over local exchanges - but the current routing technology makes
having hundreds of local exchanges somewhat infeasible.
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