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restoration time requirement (was Re: Last Call on RSVP Label Allocation for Backup Tunnels)

  • From: Curtis Villamizar <curtis@workhorse.fictitious.org>
  • Date: Sun, 08 Apr 2001 22:36:33 -0400
  • cc: "'neil.2.harrison@bt.com'" <neil.2.harrison@bt.com>, raszuk@cisco.com, mpls@UU.NET, ccamp@ops.ietf.org


In message <31236E6272C7D2119F1C0000C0A8E4F40324083D@nj0200po04.bm.att.com>, "L
azer, Monica A, NNAD" writes:
> Voice switches will drop the connections after 2.5 seconds. A large number
> of dropped calls will cause FCC reportable events, which is something that
> US carriers need to avoid. So restoration within this time frame is needed
> for support of trunks carrying voice traffic.
> 
> Monica A. Lazer
> Advanced Transport Technology and Architecture Planning
> 
> 908 234 8462
> mlazer@att.com


Monica,

We're off topic, so I changed the subject.

Thanks for providing the 2.5 second figure.

I've heard carrier transport people grumble about SONET equipment
they'd be please to get rid of that will shut down even when used as
linear SONET with no protect path and as a result would require
<100msec restoration.  Since there is enough of this SONET gear, the
carriers can't really get rid of it although it will probably
disappear over time and so they will make fast restoration a
requirement of people they buy from.  To be safe, the request for
<50msec has been made.

If you are not blessed with such equipment or you are able to work
around it when doing VoIP, then you are among the fortunate.

Then again, this is second hand, so I could be completely wrong.  This
is not a measurement I've made myself and the SONET equipment is not
something I'm familiar with such that I could say with confidence that
it could not be configured to hold on longer or to not shut down at
all if there was no protect.

OTOH there are those who (claim to) want to configure SONET on some
links but not on others and don't want a fast restoration.  They want
to be assured that restoration will occur only after it is safe to
assume that SONET restoration is not available.

Curtis