Iscom
Guest
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 Posted:
Thu Nov 24, 2005 3:26 pm Post subject:
confusion about xDSL performances |
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Hi,
I've been working at my doctoral thesis by realizing some performance
tests on VDSL systems.
Now I'm trying to understand the main differences in terms of "bit-rate
vs.reach length" of several xDSL standards in a real deployment
scenario (that means in presence of impairments like crosstalk, radio
frequency intereference, and so on).
Of course I found a lot of informations on the web, but they are almost
always "wrong".
For example, I often read that VDSL can offer bit rates like 52 Mbps or
even 100 Mbps on short loops. This is not correct: the ETSI VDSL
standard (Technical Specification 101-270) defines some service
classes, and the fastest among them is about 28 Mbps in both
transmission directions. By measuring the real performance in presence
of crosstalk, even this speed is not sustainable (my measurements and
other similar tests that one can find in the same ETSI Recommendation
confirm this).
Anybody knows about analogous standard-compliant tests on other
technologies (ADSL2, Re-ADSL2, ADSL2+,...) so that I can do a serious
comparison?
thanks in advance! |
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