Re: DSL over Frame Relay [7:76443] posted 09/30/2003
- Subject: Re: DSL over Frame Relay [7:76443]
- From: "Howard C. Berkowitz" <hcb@xxxxxxxxxxxx>
- Date: Tue, 30 Sep 2003 12:42:34 GMT
At 10:45 AM +0000 9/30/03, nrf wrote:
>""Steven Meier"" wrote in message
>> I must be thick......or having a blonde day...but DSL over frame relay is
>> impossible as they are 2 different hardware transport platforms.
>> DSL is ATM and uses completely different hardware than a frame relay
>> which uses PVC's etc whether permanent or semi permanaent.
>> The packet structure is different as well.
>> or am I completely blonde.
>I don't want to comment on your hair-color, but you can indeed have DSL over
>frame-relay. It's rare, but some DSLAM vendors support it. While DSL is
>usually backhauled through ATM, this is not necessarily so - any backhaul
>mechanism can be used in theory. It all depends on what the vendor supports
>and how the service-provider wants to build the network.
Well, I confess to being confused by this thread, even though I'm
more hair-challenged. I have no difficulty understanding the use of
DSL as a first-mile access technology to FR, as ISDN, dial and even
X.25 have been used for years.
But DSL, to the best of my knowledge, is a physical layer
specification, full of modulations, medium requirements, etc., that
feeds bit streams into a DSLAM, which may pass along bit streams on
ATM, or, if the DSLAM contains layer 2 or 3 functionality, pass
frames or packets. ADSL, SDSL, ISDL, VHSDL, etc., don't specify
frames, to the best of my knowledge.
We speak glibly of Ethernet-over-whatever, but we really are speaking
there of 802.3 frames, not Manchester-encoded baseband signals or
optical or broadband equivalents, or the OC-192 PHY for 10 GE.
DSL-over-whatever sounds like the equivalent of Manchester over
frame, essentially an analog-to-digital process.
Have people been using sloppy terminology or am I missing something
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