MCI WorldCom has a fiber cut in White Plains, NY, as of 0902 EDT this
morning. MFS service seems to be decimated, although the Brooks network
is totally intact.
At least one wireless provider (OmniPoint) has no inbound service
available to customers in the area.
No ideas as to where exactly the outage is or how long it will take for
service to be restored.
scottd@cloud9.net (Scott Drassinower) writes:
MCI WorldCom has a fiber cut in White Plains, NY, as of 0902 EDT this
morning. MFS service seems to be decimated, although the Brooks network
is totally intact.
i guess fibre is just not being laid in rings any more? why on earth should
a single backhoe cut be able to take ANY circuit out?
for the "exchange level peering" PAIX and Ames are setting up, PAIX is using
NextLink as the dark fibre provider. but PAIX is not buying a path, we are
buying a strand. it's ~250 miles long and goes all the way around the Bay.
we're going to interrupt it in two places (PAIX and Ames) with Sonet-capable
gear. when the inevitable backhoe comes, only one of the two ways around this
ring will be sliced. my hope is that we can restore that cut before the other
backhoe comes and slices at the other radian.
but i've got to say, i didn't invent this topology -- it's what i've been told
is the only way to do something like this, so i'm doing it like i was told to.
apparently noone told MFS that this was the only way to do something like this?
why pay the complexity and cost overhead of SONET if you're not building rings?
(Chuckle) When I first started looking into SONet back in'92, and later
with the Milan (Michigan) cut that took out so many "redundant" paths,
I learned that the "redundant" "ring" part of SONet was "intended" to be
preventative against an electronics failure, so that a single transceiver
failure won't kill the circuit. This is the same reason that they provision
"Automatic Protection Switching" (APS). But the two paths on the ring (and
the APS circuits) are usually both in the same fiber bundle.
For a educational network I was consulting on, they actually ran the pair of
bundles between buildings in two liner sleeves within a single duct. Saved
on right of way. So, even when you have a firm contract and circuits
specified, and it looks like a ring on paper, you have no way of knowning
that they actually gave you geographically diverse paths, without walking
the couple of hundred miles and inspecting them yourself.
APS is really a useless feature. Even when you get the contract to say there
are diverse paths, they will later groom the circuits to put them in the
same bundle.
Paul A Vixie wrote:
why pay the complexity and cost overhead of SONET if you're not building rings?
WSimpson@UMich.edu
Key fingerprint = 17 40 5E 67 15 6F 31 26 DD 0D B9 9B 6A 15 2C 32
[snip]
APS is really a useless feature. Even when you get the contract to say there
are diverse paths, they will later groom the circuits to put them in the
same bundle.
Quite right that grooming is a constant threat. Depending on the carrier,
one safeguard: when you write a contract in which you pay for facility
diversity, write in a provision that lets you audit the Data Circuit Layout
Record (or whatever the specific carrier calls it) periodically -- perhaps
every 30 to 60 days.
While they may groom both paths into a single cable, they will document
this. By Murphy's Law, of course, they will tend to groom just after
you've audited the documentation, but it's some help.
I'm trying to remember the details, but I believe it was MCI in the Chicago
or Florida area (not to single them out, just an example) that was sued
successfully for not diversifying media for which facility diversity was
specified, even though there was no actual outage.
In a IP backbone, we prefer to have 2 diverse path's to IP use, than one
with protection, this gives a better overall utilisation, and more
control of what happends.
/Jesper