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Re: [EFM] Network timing, ATM, ADSL/VDSL and EFM


I and my customers would prefer "smart pipes" to either "fat pipes" or 
"smart switches".  One of the problems that the transmission service 
providers have created is a level of support transparentcy that most people 
are unaware of.  On of the reasons that ATM is so complex is that trys to 
emulate the functionality that is inherent in the service provider Tx 
framing.  Like 802.3, most people take it for granted that transmission 
"circuits" are "plug and play" at the physical connectivity level.  They do 
not know that the vast majority of that plug and play functionality is 
because of the physical coding and signal standards.  T1/E1 etc, have a 
coding similar to what was done for 64/66 in 10GbE.  Every x number of bits 
"revenue traffic", an additional bit is added.   Unlike 10GbE, the 
additional bits in T1/E1 coding are also used to carry 
information.  Network "timing" synchronization, customer service 
labels,  remote problem resolution, and a low bandwidth comm function are 
embedded in the T1/E1 "out-of-band" overhead created by those bits.  This 
works so well and so transparently, that even the shared service people 
such as the ISPs are unaware of how the physical connectivity is maintained 
and supported.

It is also inexpensive.  A  T!/E1 CSU today costs less that what a GbE SMF 
PCI card does.  If it had the commodity market that 10/100Mb Ethernet does, 
it would probably have much the same pricing, or lower.

Thank you,
Roy Bynum

At 08:53 PM 9/30/01 -0400, Fletcher E Kittredge wrote:
>On Fri, 28 Sep 2001 15:58:14 -0700  Moshe Oron wrote:
> > I agree to what Matt wrote about QoS mechanisms being crucial mostly when
> > resources get congested. This is why the argument that ATM is 
> inefficient as
> > it involves the cell tax is not a good one. Over-engineering the link 
> to the
> > extent that prevents congestion and thus eliminates the need for QoS might
> > involve a much higher tax.
>Correct!  The key question is which is cheaper: fat pipes or smart
>switches and CPEs?  This would be a question for the market-place.