Neither it is a bad phenomenon per se -- it reflect shifing of Internet
being add-on service to being a core business of facilities based
telecom companies. The ultimate win will be a network which is a lot
more useful, with solid and sustainable business model.
--vadim
Of course there are those that simply see the PSTN as just one more way to
move IP packets about. Lets see; radio, wireless, sat-link, cable, lans,
PSTN, avian-carrier, seismic-wave... lots of ways to move IP packets about.
the PSTN is one, but not the only one. And its not clear there is enough
capacity in the PSTN to carry all the bits about. Its not clear to me that
ATM will continue to work at terabit rates.. SAR may be a bit tough to do
at OC768-ish rates. And then there is all that PSTN infrastructure that will
have to be replaced... push all that back on the rate payers? you bet.
I though that ATM cell sizes were so small in order to better support
real-time voice and video. We are already getting to the point where
1500 byte IP packets can be transmitted end to end in the same or less
amount of time as the original ATM networks were planned to be. When data
rates get this high, is there any good reason to shred packets, other than
maintaining compatibility with obsolete ATM gear?
Michael Dillon - Internet & ISP Consulting
http://www.memra.com - E-mail: michael@memra.com
The bottom line is track record. Not track tearing. Not track derailing.
But pounding the damn dirt around the track with the rest of us worms.
-- Randy Bush
I though that ATM cell sizes were so small in order to better support
real-time voice and video.
The original ATM compromise was designed to avoid screwing up echo
cancellation on the last mile loops which is very sensitive to delay and
hard to adjust since it is old fashioned analog hardware and not digital.
That is one of the more difficult aspects of the new xDSL technology is
dealing with echo cancellation and crosstalk in those crummy old two-wire
circuits.
We are already getting to the point where
1500 byte IP packets can be transmitted end to end in the same or less
amount of time as the original ATM networks were planned to be. When data
rates get this high, is there any good reason to shred packets, other than
maintaining compatibility with obsolete ATM gear?
In a word "No". However, there is no good reason to fix the length at 1500
bytes. We could set the maximum to 1500 bytes and allow these cells to be
shorter. We could come up with a connectionless addressing scheme, perhaps
one that the hardware manufacturers can administer. Let's be generous and
say 48 bytes long.
What? Oh, right, IEEE already did that with 802.3 MAC. Never mind.
--Kent
~~~~~ ~~~~~ ~~~~~ ~~~~~ Note new area code ~~~~ ~~~~~ ~~~~~ ~~~~~ ~~~~
Kent W. England Six Sigma Networks
1655 Landquist Drive, Suite 100 Voice/Fax: 760.632.8400
Encinitas, CA 92024 kwe@6SigmaNets.com
Experienced Internet Consulting ~~~~~ ~~~~~ ~~~~~ ~~~~~ ~~~~~ ~~~~
(If you can't reach me using 760 area code, use the old 619 instead.)
bmanning@ISI.EDU writes:
And its not clear there is enough
capacity in the PSTN to carry all the bits about.
The hard part is stringing fibre around, followed by
figuring out clever ways of lighting it up.
North America is Geographically Challenged in that respect
compared to the greater number of shorter rights-of-way
among large customer bases in other parts of the world.
For now there is some coasting going on in the U.S. and
Canada particular since the traffic crunch is mostly
north-to-south. However ultimately trunking east-to-west
will fill and that is a much harder bottleneck to widen,
and provides interesting opportunties to people deploying
things other than fibre in the U.S. Of course, such
deployments strike me as unstable economically principally
for scaling and failure-avoidance-and-recovery reaosns
compared to modern fibre technology.
Of NANOG relevance, there are ample war stories of
weather-sunspot-and-bat-releated outages on high-bandwidth
alternatives to terrestrial paths. *I* wouldn't use a
non-fibre (and ideally non-SONET) path where one were
avialable if losing connectivity (or alot of capacity)
when it stops working were an issue.
Sean.