# Summary of 3GPP Technical Document S4-260117

## Document Information
- **Specification:** TS 26.113 v19.1.0
- **CR Number:** 0015
- **Category:** F (Correction)
- **Release:** Rel-19
- **Work Item:** iRTCW-TEI (Interactive Real-Time Communication Web - Technical Enhancement and Improvement)
- **Source:** Qualcomm Inc.

## Purpose and Rationale

The CR addresses an ambiguity in the SWAP (Streaming and WebRTC API) specification regarding the handling of the accept message in response to a close operation. Currently, the specification is unclear about whether the answer field (containing SDP answer) should be included in the accept message when responding to a close message, leading to potential implementation confusion.

## Technical Changes

### Accept Message Handling (Clause 13.2.4.4.5)

#### Description Updates (13.2.4.4.5.1)
- **Previous behavior:** Accept message always contains answer SDP when replying to connect or update requests
- **Clarification added:** 
  - Accept message shall contain answer SDP when responding to connect or update messages
  - Accept message shall NOT contain SDP when responding to close messages
  - Explicitly separates the two use cases for the accept message

#### Parameter Definition (13.2.4.4.5.2)
- **answer parameter:** Changed from mandatory to optional
  - Modified to "This parameter, **when present**, shall contain the answer SDP"
  - Makes it clear that answer is conditionally included based on the triggering message type

### Update Message Clarification (13.2.4.4.6.1)
- Reinforces that update message is for partial media teardown (half-close)
- Distinguishes from close message which performs full session termination
- Note added emphasizing the use of close message for full session termination

### Close Message Clarification (13.2.4.4.8.1)
- Explicitly states that accept message response shall be "without an SDP payload"
- Clarifies session teardown procedure: accept message triggers resource release
- Note added distinguishing close (full termination) from update (partial teardown)

## Impact

The changes ensure proper protocol behavior by:
1. Removing ambiguity in accept message structure based on context
2. Preventing unnecessary SDP exchange during session termination
3. Clearly delineating between partial media teardown (update) and full session termination (close)