Applications such as video conferencing or data storage
using storage area networks (SANs) require a symmetric transmission channel.
File-sharing applications, as well as peer-to-peer traffic such as eDonkey, Kazaa, and
Napster (to name just a few of them), increase traffic symmetry since each connected
user simultaneously operates as network client and server, thus receiving and transmitting
on average the same amount of data. It was recently reported that the current
ratio of downstream to upstream traffic is approximately 1.4 to 1 [4]. The recent
advent of IPVideo services and video file hosting services i.e. YouTube seems to skew
this ratio again towards strong asymmetry (YouTube video sessions account for 20% of
overall HTTP transactions and 10% of the overall traffic observed on the networks) [5].
As a result of streaming audio and video in Web downloads, HTTP traffic constitutes
approximately 46% of all data transmitted over Internet, while the ratio itself has a
strong positive increase factor. For comparison, symmetric P2P traffic constitutes in
total roughly 37% of data being transmitted.
For some time, it has been expected that the traffic ratio would reach the full symmetry
condition (1 to 1), with downstream and upstream data flows more or less balanced.
Pages:
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446