DSL Standard On Track
(05/20/98; 1:02 p.m. EST)
By Salvatore Salamone, InternetWeek
techweb.com
International standards for digital subscriber line
technology remain on track. At least, that is the news
from last week's meeting in Sophia Antipolis, France, of
the International Telecommunications Union study
group in charge of drafting the standards.
According to reports from attendees, 84 people
representing 45 organizations met for three-and-a-half
days and ironed out some of the remaining obstacles to
international DSL standards. The group plans to have
the standards technically complete, which is what the
ITU calls "determined," by the next meeting in late
October.
All told, the study group made progress on five
DSL standards. These include:
G.dmt, an Asymmetric DSL standard that uses
discrete multitone encoding for transmission rates up
to 8.192 megabits per second downstream (from the
service provider to the user) and 640 kilobits per
second upstream (from the user to the service
provider).
G.hs, (G.handshake), which like handshaking
techniques used with modems, defines a start-up
procedure that allows support of different DSL versions.
G.lite, a lower data rate version of G.dmt. The data
rates being considered for G.lite are up to 1.5 Mbps
downstream and up to 512 Kbps upstream. DSL
systems using G.lite are expected to be less costly to
install than products based on other DSL technologies
because G.lite does not require the service provider to
install a splitter in a user's home. A splitter separates
the low frequency voice traffic from the higher frequency
DSL data traffic.
G.ploam, (physical layer operations administrations
and maintenance), which gives service providers the
ability to manage and provision DSL systems.
G.test, a standard that will be used by equipment
vendors to ensure compatibility of different vendors'
products.
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