Slide 8 of 29
Macs 828, PCs 1357, Unix 649, Xterms 375, VMS 202 = total ~ 3500
Metcalfe’s law: bandwidth grows with square of number of devices connected
80/20 rule fails due partly to centralization, so growth at periphery may not be
as high as in center (e.g. on backbone or on Internet). Don’t see video
driving bandwidth needs (compression helping, difficulty of use, questionable
need for talking heads). Expect more from more sophisticated applications,
audio/video clips (e.g. in email & Web), and further out streaming video.
Do not expect NetPC/NCs to challenge PCs.
Significant driver for increased periphery bandwidth is the increased
number of high performance PCs. # increasing by ~ 30% per year. Processor
speed doubling every 18 months ( => 100,000 MIPS in 2011 - Andy Grove).
Data storage doubling/year. However need balance with memory and I/O access,
which is lagging. PCs cannot keep up with Gbps today so do not see it going
to periphery for a while, so expect copper to desktop to dominate for a while.
Network is lightly loaded (e.g. FDDI backbone has a average of 5% utilization)
and 5 minute peaks seldom exceed 35%. This over-engineering is by design to
keep away from the edge of the envelope, reduce management costs and the
critical factor is NOT the utilization of the link but the ability to get work done
(e.g. typical car gets is only used for 5% of the time).