Donald Neal wrote:
Alastair, you know that telco "five nines"
tends to apply to a subset of
the network, not necessarily to a single customer connection.
Yes, that's correct. Although there are many telcos that define
explicitly how their SLA is measured, and on what components it affects.
I've personally signed contracts with a few telcos that make mention of
access SLAs vs. the core SLAs.
Are you sure there's a good reason to deploy 48V
DC to customer premises
beyond that being needed for the SDH kit? A chain of devices with
customer premises mains supply at one end adds single points of failure
for the connection. Is the improvement in power quality worth it?
I never suggested it was a good reason or should be done - but that
perhaps the MetroE providers should look at how telcos have delivered
high availability (whether it's five nines or not) in high value
services. Whether MetroE costs a little or a lot, many people are
placing high *value* on it - and part of that value should be around
"how do we make sure it works as close to all the time as possible".
It's been said that UPS' don't scale (even I agree with this), yet
somehow the telcos have managed to deploy many services with active
electronics at the customer end, where they have also deployed their own
power protection systems.
Perhaps there's a market for Cisco and other vendors to introduce MetroE
switches/NTUs with batteries built in.