Subject: [GSMP] Opinion requested: Restoration functionality

From: avri <[email-masked]>
Date: Fri, 20 Jun 2003 21:15:44 +0900

Section 2.8 of draft-ietf-gsmp-reqs-06 references
OXC restoration capabilities.  I am finally working
on the update of the base spec.

Is the restoration info specific to optical technology or
would it be useful as a general part of the base spec.

i.e. are technologies outside of optical likely to use
the protection mechanisms?

Answers to the list please.

thanks

a.

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From: "Stephen Shew" <[email-masked]>
Date: Fri, 20 Jun 2003 09:29:55 -0400

Protection functions are not exclusively found in transport switches.  For
example, ITU-T recommendation I.630 defines ATM protection.  One could also
consider backup next hops in an IP forwarding table a form of restoration.

In transport architecture there is a difference between protection and
restoration. Generally speaking, protection involves the repair of a link
connection without affecting the endpoint of the circuit.  Restoration
involves the repair of a circuit that includes changing the endpoint (like a
dropped telephone call followed by redialing).  The draft only addresses
protection.

Protection mechanisms can apply to circuit based switches (TDM, SDH, etc.).
I don't think they are fully applicable to packet based switches (IP, ATM).
For example, in 1+1 protection the source switch sends traffic down both
working and protection paths.  I don't know of any packet service that does
this between the same source and destination.

So, I think that protection has some general and some specific technology
application.  It doesn't not seem to apply though to packet switching.

-----Original Message-----
From: avri [mailto:[email-masked]] 
Sent: Friday, June 20, 2003 08:16
To: [email-masked]
Subject: [GSMP] Opinion requested: Restoration functionality

thanks

a.