On Wed, 6 Feb 2013, Scott Helms wrote:
The cost difference in a single interface card to carry an OC-3/12 isn't significantly more than a Gig-E card. Now, as I said there is no advantage to doing ATM, but the real cost savings in a single interface are not significant.
There has always been a substantial price difference for ATM/POS compared to ethernet. But when designing ETTH networks, the cost saving is in the use of very simple devices. L2/L3 switches all the way. No tunneling, no fancy encap/decap Q-in-Q etc. Enough intelligence to do the BCP38 stuff to prevent spoofing, MitM-attacks, nothing more, but still deliver needed services over unicast and multicast. So as soon as the design contains any of the words L2TP, PPPoE/A, ATM, POS, OC-whatever, xPON or anything like it, you're incurring unneccessary cost, especially for high bw services. The most inexpensive device to L3-terminate 10GE worth of traffic from a few thousand customers is in the few thousand dollar range, what's the cost if you want to do the same using L2TP or PPPoE ? What about ATM? I don't even know if ATM on OC192/STM64 is even widely available. My guess is anyhow that you're not looking at a device that costs at least 5-10x the cost. Designing a fiber plant very much like the traditional copper plant, ie aggregating thousands of households in a single pop, and letting "anyone" terminate that fiber, is a very future proof and scalable approach. The fiber can be lit up using any technology (active p-t-p ethernet, or PON, or whatever is desired), this doesn't have to be chosen at time of actually drawing the fiber. Yes, it's a high initial cost but I firmly believe that over tens of years of lifetime of the fiber, this cost is lower than other solutions. -- Mikael Abrahamsson email: swmike@swm.pp.se