VERMOUTH for MARTINI SIP MARTINI Variant of 'Event-package for Registrations‘ for Managed Open-ended Username Target Handling (VERMOUTH) draft-kaplan-martini-vermouth-00 Hadriel Kaplan

The Problem GIN gives us reg-event for PBX side, but… It’s also useful for Martini in the SSP side –For systems to learn when the IP-PBX is registered and its path/contact info –For the IP-PBX et al to verify/learn what AoRs the SSP associates with it –For SSP to Notify IP-PBX of adds/removes But the usernames may be open-number-plan or Local Numbers –Each actual possible username is unknown to SSP –And it may be a very big list if it is known

Mismatched provisioning: a real problem When SSP and PBX AoRs don’t match, bad things happen: –Calls fail to reach PBX –Calls loop (badly) Sometimes the error is caught quickly, but usually not until it’s actually called It takes time to troubleshoot, and reducing that time saves money and customer frustration

Possible Solutions 1.Use reg-event, define a syntax to handle open/wildcard usernames for AoRs in reg- event 2.Subscribe to something new (not reg- event) to learn about provisioned AoRs 3.Use PUBLISH to push from SSP to PBX VERMOUTH currently does #1, but it’s tempting to go for #2

Proposed Solution in Draft Define a new “Bulk-AoR” for reg-event –Uses new “range” user param to indicate range –E.g.: bulk-aor-user = user ";range=" expansion expansion = exp-char-set exp-char-count exp-char-set = digit-char-set / any-char-set digit-char-set = dsc-begin "-" dsc-end dsc-begin = DIGIT dsc-end = DIGIT any-char-set = "." exp-char-count = "(" exp-min "," exp-max ")" exp-min = DIGIT exp-max = DIGIT

Why not regex? Some common regex characters are not allowed in SIP URIs and would need to be escaped –^, [, ], {, } Regex patterns are good for figuring out if a given string matches the pattern, but not what all possible strings matching it are –E.g., you can tell if matches, but not that and also match –In other words, it’s hard to tell if the SSP thinks more usernames belong to the PBX than the PBX does There are numerous patterns which match the same strings

Example reginfo XML <reginfo xmlns="urn:ietf:params:xml:ns:reginfo" xmlns:xsi=" version="0" state="full"> <registration id="as9" state="active"> <contact id="76" state="active" event="registered" duration-registered="7322" q="0.8"> sip: ;bnc <contact id="77" state="terminated" event="expired" duration-registered="3600" q="0.5"> sip: ;bnc

Subscribing The current 00 draft has the SSP process Subscribes to the AoRs, but GIN now does the opposite: normal Subscribes go to the PBX –GIN wins, so VERMOUTH draft will change The question is what URI syntax to use for the PBX to subscribe to the SSP for the data –E.g.,

Choosing Option-2 It’s tempting to define a new bnc-reg-event package –Can be made more efficient, because all AoR’s share same contact/path info –Don’t need to create a Bulk-AoR format as a URI – just do it as explicit XML –New package name lets SSP route it to appropriate server in SSP

Questions Is this a problem worth solving? Is there interest to do so in this WG?

Open Issues

Bulk AoR format Should we just use regex and escape illegal characters? Since the URI user type is of a specific type, should we create a new ‘user’ param enumeration value? –E.g., “;user=bulk” similar to user=phone

What about -style AoRs? Currently VERMOUTH includes this in the range syntax –E.g., “ ” But in practice they probably won’t work this way and would need to be enumerated, possibly leading to large sets –And reg-event’s XML schema is inefficient for that case