[137482] in North American Network Operators' Group
Re: Packet over SONET failback
daemon@ATHENA.MIT.EDU (Per Carlson)
Mon Feb 14 08:13:04 2011
In-Reply-To: <FB8B64B2-E05A-4200-97AC-D40FB6BBC9B9@lixfeld.ca>
Date: Mon, 14 Feb 2011 14:12:16 +0100
From: Per Carlson <pelle@hemmop.com>
To: nanog <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hi Jason.
>>> PoS failure detection happens in under 50ms
IMHO this is the most important part, fast *down* detection.
> It's not actually SONET all the way through. It's GigE from the router t=
o the SONET node, an unprotected OC192 wave to another node, out GigE to th=
e far end router.
If the gear manages to shut down the GE lasers within the 50ms, you
have no rights at all to complain :-)
> I'm not necessarily talking about forwarding of packets here, I'm talking=
simply about the time it takes the far side interface to come back up over=
a SONET node; layer 1. =A0Maybe this has nothing at all to do with SONET, =
I dunno :) =A0 It was gleaned that the next step might be to look at the SO=
NET node and see if it's waiting 15 seconds to turn the laser back on or so=
mething.
A 15 second wait before enabling the path is a good thing. Nothing
worse than switch back to a path and experience a second down event
(and thrid, forth etc.). If it's been up 15 secs, it probably is safe
to use.
--=20
Pelle
RFC1925, truth 11:
=A0Every old idea will be proposed again with a different name and
=A0a different presentation, regardless of whether it works.
