IETF 70 BLISS WG meeting

1. IETF 70 BLISS WG meeting Automated Handling draft-elwell-bliss-ach-analysis-00draft-elwell-bliss-dnd-01

2. Topics • draft-elwell-bliss-ach-analysis (automatic call handling analysis) • draft-elwell-bliss-dnd-01 (do not disturb) • Discussion

3. draft-elwell-bliss-ach-analysis • Identifies many examples of conditions that can give rise to ACH • Identifies various actions that can be taken when conditions are met (typically forward elsewhere or reject) • Discusses a number of problem areas • Identifies questions that BLISS needs to answer to take this topic further

4. ACH problem areas • Interactions between proxy and UA • Which “wins” depends on whether call ever reaches the UA • Also depends whether proxy can figure out what UA has done and override with own action • Conflict between UAs • Depends whether serial or parallel forking (latter less deterministic) • Proxy determination of what has happened at UA • Are response codes precise enough (e.g., for DND)? • Informing the calling user • Similar to above, but privacy may play a part • Redirection versus retargeting

5. ACH problem areas (continued) • Scope of conditions • Does a proxy wait for all UAs to respond, or act when first UA reports a given condition? • Scope of 6xx response • Does it include voicemail? • Does it include forwarding to a different AoR? • Configuring the proxy • Several different ways (e.g., web page, web service, CSTA, CPL upload) • Related issue of whether UA and user can view what is configured at proxy

6. ACH - other points discussed • Proxy versus UA • Lot’s of good reasons for doing ACH at the proxy • But can be particular reasons for UA-specific ACH • May be different considerations for enterprise and residential environments • Avoiding inconsistent configurations • Use of configuration framework to ensure consistency, whilst still allowing UA-specific behaviour where required • Possible approach is to download policy to UA indicating whether proxy is responsible for ACH

7. ACH – questions identified • Do we need to make any recommendations on proxy-based versus UA-based ACH? • Is provisioning (e.g., using SIP config framework) a suitable solution for ensuring consistency between UAs and between UAs and proxy? • Do we need to make any recommendations on response codes and other information in responses between UAS and proxy?

8. ACH – questions identified (continued) • Do we need to make any recommendations concerning meaning and use of 6xx response codes? • Do we need to specify a recommended or default method for a UA or PDS to configure its proxy and discover how its proxy is configured? • To what extent is it necessary to make recommendations concerning keeping the calling UA informed of what has happened?

9. draft-elwell-bliss-dnd-01 • Changes from 00: • additional means of invoking DND (casual, based on sensing a user's current activity) • distinction between conveying DND to a proxy and conveying the condition to the caller • problem of indicating DND to a caller when the condition does not relate to the original called party (e.g., the call was forwarded first) • whether to wait for all branches to respond or act immediately a branch reports DND • Further work will depend on general ACH work (but not a total overlap, e.g., presence aspects of DND)