Help understanding VDSL

[gmail2]

Hi all

I'm trying to understand how VDSL works and need some help. I've just done a site survey & discovered 2 of these connections, Ive been told they are "LAN extenders" (running between 2 factory buildings). I presume they are a cheaper alternative to fibre

But what I'm wondering is, are they just point to point between the 2 buildings ? Or is each end connected to the Telco & therefore the traffic between the 2 sites goes through the telco ?

If they are connected directly to each other, does this mean there are no recurring monthly costs (normally) & that the only cost is the initial setup ?
Also, if it's not a direct connection between the 2 buildings, how does the ISP route the traffic between the 2 buildings ? Is there some "tagging" sone by the VDSL device at each end so that the Telco knows whre to route the traffic between the 2 buildings ?

Final question ... I presume these "LAN Extenders" work at layer 2, therefore the LAN at both buildings can share the samesubnwt ? Can somebody clarify for me ?

Thanks in advance for any help

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[Stelios]

Hi,

Since VDSL is another flavor of DSL technology there must be a DSLAM somewhere around the neighborhood.
VDSL modem should be connected on the copper pair running from each factory to the DSLAM.
Maximum available bit rate is around 50Mbps and is achieved at a range of about 1.2Km, then the DSLAM should be close by. Probably in a cabinet (owned by Telco ) on a pavement.

Yes probably it is cheaper from fiber.

But will it be ok in an industrial area? i'm not sure about that. Industrial Areas are known to have voltage spikes and surges and a lot of interference from electric machines.
But perhaps these problems are filtered somehow.

Traffic may go through Telco or not.
This depends on the capabilities of the DSLAM. If it can give you layer 2 between the 2 copper lines then traffic does not go to Telco.see VLAN-per-service.

LAN at both buildings would be connected through this service, like if you had a long Ethernet cable.
But it all depends on the down/up speeds of this service

i don't see the same bandwidths in many documents
Somewhere it says 55 Mbps down/15 Mbps up, elsewhere says 100 Mbps downstream and 50 Mbps upstream.

BTW, VDSL2 has speeds of 100 Mbps downstream and 100 Mbps upstream

For more links check the following links that explain VDSL and VDSL2.

http://www.ericsson.com/ericsson/corpinfo/publications/review/2006_01/files/vdsl2.pdf

http://www.ericsson.com/ericsson/co...ate/archive/2009/issue_2/articles/vsdl2.shtml

http://www.broadband-forum.org/downloads/About_DSL.pdf

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Stelios