Subject: [V3] Current RIPT drafts - TLD summary of all four and key points to know

From: Jonathan Rosenberg <[email-masked]>
Date: Fri, 14 Feb 2020 22:14:36 +0000

To help get discussion going - here are the four drafts that we've got submitted on this topic and some of the key design decisions which are likely to spark comment:

https://datatracker.ietf.org/doc/draft-rosenbergjennings-dispatch-ript/

The core protocol. Basically sends signaling, media and codec negotiation over http3.

Uses webtransport + fallback to a single transaction per media chunk to ensure no HOL blocking
Bidirectional event streams for signaling for calls using long-running GET and PUT (answered, proceeding, end, etc)
Auto-configuration for URIs and bearer tokens for sip trunking use cases
Caller ID ONLY via STIR passports - verifier role is not used because client gets a cert and inserts passport itself
Media negotiation is NOT offer/answer - its an advertisement/directive model where advertisement is relatively static, and server just tells client what to do (directive)
Only supports outbound calling, not inbound. Inbound calls supported by provisioning a 'terminal group' aka 'TG' (similar to trunk group) in reverse direction - for sip trunking
TG construct tells the client what phone numbers it can use as callerID and what numbers it can call outbound

https://datatracker.ietf.org/doc/draft-rosenberg-dispatch-ript-inbound/

Extension that focuses on single-user device cases - softphone, IP phone, video endpoint.

Assumes client gets push notifications out of band - not handled by this spec (so this is NOT like sip-outbound)
Extends core protocol to allow for events that support receiving calls and answering them
Multi-device (multiple phones for same user) is natively supported in the core protocol not via 'forking' but through server resource model
Description on how to handle common single-user device cases like call move, pull, remote-in-use, etc. which are all easy when state is on server

https://datatracker.ietf.org/doc/draft-rosenberg-dispatch-ript-sipdiffs/

This doc is basically "WTF is this RIPT thing, for SIP people". So if you've never heard of sip you don't need to read this doc.
Reviews the significant design chocies made by RIPT which differ from SIP (many of which are merely inherited by being an http app)
Analysis of how much of SIP specs are replaced by RIPT (incomplete)

https://datatracker.ietf.org/doc/draft-rosenberg-dispatch-ript-webrtc/

Sketch of thoughts on webRTC and p2p media with RIPT

Thx,
Jonathan R.

--
Jonathan Rosenberg
CTO and Head of AI, Five9

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