Date: Sat, 29 May 2004 14:26:01 -0400
From: Matthew Crocker
The PSTN does guarantee a certain service level, latency,
call completion etc.
As do many Internet providers. (s/call completion/packet loss/)
Latency & Jitter are very important when dealing with sound &
video. Or anything realtime for that matter. The Internet
isn't just HTTP, NNTP, SMTP any more.
Nitpicking: Latency isn't that important with unidirectional
communication. However, VoIP users seem reasonably happy with
current latency and jitter -- and the Internet still is _largely_
xxTP, anyway... particularly if one ignores peer-to-peer file-
I remember quite a bit of packet loss when the last series of
As do I, but I consider that an exception, not part of standard
operation. Admittedly, that may well be an error on my part,
considering the increasing popularity of worms and viruses. The
PSTN doesn't have botnets of "pwned" phones making prank calls.
(Further note that MAE FDDI congestion was more frequent than the
current malware field days.)
However, I see this as a problem of securing machines, not one of
best effort delivery. Choke trunks are used to prevent radio
call-ins from overloading the PSTN.
Perhaps throttling bandwidth using a slow-moving exponential
decay, over a long averaging period, is a good idea. One could
allow short bursts of line-rate traffic.
End-user duty cycles are low. This is what facilitates current
levels of statmuxing, and why packet loss skyrockets when many
systems try to operate at line rate for extended durations.