>>On Thu, 04 Oct 2012 09:20:07 -0700, Jeff Liebermann <je...@cruzio.com>
>>wrote:

>>>Not bigger network, but different network.  The definition of a router
>>>is a device that connects two DIFFERENT networks at the IP layer (ISO
>>>layer 3).  One port is connected to the greater internet network.  The
>>>other port is connected to a local area network, that uses
>>>non-routeable IP addresses.

>>I mostly agree with your distinction on the difference between modem and
>>router.

>It's an oversimplified definition, which falls apart on devices like a
>brouters (bridge-router) and using a DSL modem to simultaneously
>connect to multiple services.  Simple definitions never seem to stay
>simple.

>>>My definitions, which might be different than yours:

>>>DSL Modem:  DSL (actually ATM) to ethernet bridge.  Everything done at
>>>the MAC layer (ISO Layer 2) with no involvement with IP layer (ISO
>>>layer 3) except for configuration management.

>>I do not think that what is appearing at the DSL end user terminals is ATM
>>but closer to VT45 or VT135 with highly compressed data.  Moreover you are
>>looking at data likely being a shared service with a much more broadband
>>(TV) type service on the same pair.

>>?-)

>Ok, you got me.  What is V45 and V135?  Google wasn't particularly
>helpful by suggesting that VT meant vacuum tube.  Are you thinking of
>AT&T U-Verse IPTV service which uses VDSL?  If so, I know nothing
>because AT&T doesn't offer it in my area.

>The DSL modem with diagnostics include "ATM Ping" which should be a
>clue.  Articles on how DSL works always mention ATM as the underlying
>virtual circuit mechanism to connect to the DSLAM (ATM switch) which
>does the IP packet reassembly from the tiny ATM pieces.
><http://www.eetimes.com/electronics-news/4140135/ADSL-Technology-Expla...>
>See section "ADSL and ATM".