[c-nsp] T3 or Ethernet delivery?

[Seth Mattinen]

One of my carriers has given me a choice for a new circuit delivery: T3
or Ethernet. My outside world circuit experience is all non-Ethernet, so
I have a few questions the sales group wasn't able to answer. I'd love
to hear some real world experience. The cost difference between the two
is not significant enough to be the sole deciding factor and I'm not
using pure-Ethernet platforms so it's just a matter of adding the right
interface card.

How do you detect a "down" condition on Ethernet? My experience is that
the interface could be up/up because Ethernet doesn't know about
anything further down the line and ends up throwing packets into a
magical black hole. Or worse, secret packet loss.

Can you even troubleshoot Ethernet? Normally if I'm seeing something
like out of frame errors or AIS, I can say "hey, there's a problem and
it's X". It scares me to think of opening trouble tickets as "it's
broken and I can't really tell you why".

With a T3 I can be fairly certain that if there aren't any alarms that
my end is happily talking to the other end. How does one accomplish the
same with Ethernet? A periodic "ping" seems rather ambiguous as a health
check.

Since this is an outside world connection (i.e. I'm not in a colo) the
slightly lower cost and convenience factor of Ethernet doesn't override
my desire to stick with a T3 for its management properties and the
sleeping good at night feeling I get knowing there are no alarms. My gut
tells me to stick with it even though Ethernet delivery is what all the
cool kids are doing these days, so any insight is appreciated. Thanks!

~Seth