Re: [PWE3] Mandatory Control Word

Stewart,

	I agree with your suggested limitations to new PW types
and suggestion to recommend its use for existing PW types.

	However, the observation about deployed systems - when
taken together with what appears to be a growing impression
that use of the control word with all PW types may be a good 
idea - seems to argue that we would (eventually) need a BCP
that specifies use of the control word, and possibly we may
even have to publish a "non-use of PW control word considered 
dangerous" RFC.

	I don't see a way to avoid this, assuming that is where
we are headed, but it might be good to be clear on whether or
not that _is_ where we are headed.

	It also causes me to wonder if there are implementations
deployed in the field where use of the control word is not a
configurable capability.  Certainly, if deployed equipment is
all capable of being configured to always use control words,
then it is not unrealistic to suggest that configuring things
that way would simplify future implementations.

--
Eric

-----Original Message-----
From: pwe3-bounces@ietf.org [mailto:pwe3-bounces@ietf.org] On Behalf Of Stewart Bryant
Sent: Tuesday, October 26, 2010 1:24 PM
To: pwe3
Subject: [PWE3] Mandatory Control Word

From

draft-delregno-pwe3-mandatory-control-word/

=======
2.  Mandatory Control Word

    The Control Word SHALL be mandatory for all PWE3 encapsulations.  The
    use of the sequence number remains OPTIONAL.

    As a result of the Control Word being Mandatory, all implementations
    of the PWE3 encapsulations SHALL follow Section 6.1 of [RFC4447]
    wherein the "PWs MUST have c=1".  This requirement SHALL remain until
    such time, if ever, RFC4447 is superceded and the support for Control
    Word negotiation is removed as a result of this mandate.

======

Given the reality of network deployments I do not see how we can
talk about removing the requirement to negotiate the CW in any
realistic time frame.

It's fine to require the CW for all new PW types, and it's
probably OK to RECOMMEND operation with the CW, but it's
unrealistic to remove the option given the extent of the deployed
systems.

- Stewart

_______________________________________________
pwe3 mailing list
pwe3@ietf.org
https://www.ietf.org/mailman/listinfo/pwe3