[Dime] RFC4006bis - Subscription-Id-Extension AVP

[Yuval Lifshitz <[e-mail]>]

Hi All,
As part of the RFC4006bis work there are several AVPs that we plan on making future proof (See also: https://trac.ietf.org/trac/dime/ticket/95). For example, Subscription-Id AVP cannot be extended to new types without changing the enumeration in Subscription-Id-Type AVP, which in turn requires a new application ID (something we really want to avoid).
To solve this issue we propose adding a new, extendable AVP. In this example:

Subscription-Id-Extension ::= < AVP Header: XXX >
                             [ Subscription-Id-E164 ]
                             [ Subscription-Id-IMSI ]
                             [ Subscription-Id-SIP-URI ]
                             [ Subscription-Id-NAI ]
                             [ Subscription-Id-Private ]
                            *[ AVP ]

When looking into Subscription-ID-Extension AVP  header flags I ran into a problem. The existing Subscription-ID AVP (and its sub-AVPs) are all marked with the M-bit as a "must", probably because they hold the subscriber's name which is critical information.
However, in order for a RFC4006bis CC client to be able to communicate with an RFC4006 CC-server, they will have to be marked as "may".

Would appreciate your point of view on that topic?

Best Regards,

Yuval