> For the complete documentation index, see [llms.txt](https://www.conserver.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.conserver.io/extensions/sip-signaling.md). # SIP Signaling Shows how to keep SIP call identifiers, raw signaling and STIR/SHAKEN data with the recording, so a vCon can be matched to carrier logs and caller authentication can be checked later. **Draft:** [`draft-howe-vcon-sip-signaling-00`](https://datatracker.ietf.org/doc/draft-howe-vcon-sip-signaling/) ยท **Extension token:** `sip-signaling` ## Purpose of the extension A vCon built from a SIP call keeps the audio and the parties, but core-04 only has room for the party `sip` and `stir` values and the dialog `session_id`. Call-IDs, dialog tags, CSeq numbers, the raw INVITE, the SDP and the STIR certificate chain are lost. That data is what you need to match a vCon to carrier logs, investigate fraud, or check caller authentication under rules such as the TRACED Act. This extension adds optional party and dialog parameters and a set of attachment `purpose` values to carry it. The extension is Compatible (draft Section 3.1). A vCon that uses any of its parameters or purposes SHOULD list `sip-signaling` in `extensions`. The token MUST NOT be listed in `critical`. ## Example A reduction of the draft's Appendix B.1, updated to core-04 (`"vcon": "0.4.0"`, `uuid`, `created_at`, a `sip:` scheme on party `sip`) and with a lawful basis attachment added: ```json { "vcon": "0.4.0", "uuid": "01a1125f-3397-860d-832a-bc92ac6830cd", "created_at": "2026-01-15T14:30:00Z", "extensions": ["sip-signaling", "lawful_basis"], "parties": [ { "tel": "+12025550100", "sip": "sip:alice@example.com", "name": "Alice", "stir": "eyJhbGciOiJFUzI1NiIsInBwdCI6InNoYWtlbiIsIn...", "sip_contact": "sip:alice@pc33.example.com", "sip_user_agent": "ExamplePhone/2.1", "sip_display_name": "Alice A." }, { "tel": "+12025550199", "sip": "sip:bob@biloxi.example.com", "name": "Bob" } ], "dialog": [ { "type": "recording", "start": "2026-01-15T14:30:05.200+00:00", "duration": 312.5, "parties": [0, 1], "mediatype": "audio/x-wav", "url": "https://example.com/recordings/call-1.wav", "content_hash": "sha512-GLy6IPaIUM1GqzZqfIPZlWjaDsNgNvZM0iCONNThnH0a75fhUM6cYzLZ5GynSURREvZwmOh54-2lRRieyj82UQ", "sip_call_id": "a84b4c76e66710@pc33.example.com", "sip_from_tag": "1928301774", "sip_to_tag": "a6c85cf", "sip_cseq": 314159 } ], "attachments": [ { "purpose": "sip-invite", "start": "2026-01-15T14:30:00.000+00:00", "party": 0, "dialog": 0, "mediatype": "message/sip", "encoding": "base64url", "body": "SU5WSVRFIHNpcDpib2JA..." }, { "purpose": "sip-response", "start": "2026-01-15T14:30:05.200+00:00", "party": 1, "dialog": 0, "mediatype": "message/sip", "encoding": "base64url", "body": "U0lQLzIuMCAyMDAgT0sN..." }, { "purpose": "lawful_basis", "start": "2026-01-15T14:30:00Z", "party": 0, "dialog": 0, "mediatype": "application/json", "encoding": "json", "body": { "lawful_basis": "legitimate_interests", "expiration": null, "purpose_grants": [ { "purpose": "recording", "granted": true, "granted_at": "2026-01-15T14:30:00Z" } ] } } ] } ``` The `stir`, `body` and `content_hash` values are truncated or placeholder values, as in the draft. The draft's B.1 example still says `"vcon": "0.0.2"` and writes party `sip` without the `sip:` scheme; core-04 defines `sip` as an RFC 3261 addr-spec, which includes the scheme. ## Party parameters All optional (Section 4). They supplement the core `sip` and `stir` parameters. | Parameter | Type | Value | | ------------------ | ------ | ------------------------------------------------------------------- | | `sip_contact` | String | addr-spec from the Contact header, scheme included | | `sip_user_agent` | String | Full User-Agent header value | | `sip_display_name` | String | Display name as claimed in From or To, which may differ from `name` | ## Dialog parameters All optional (Section 5). When both are available, include `session_id` and `sip_call_id`. | Parameter | Type | Value | | -------------- | ----------- | ------------------------------------------------------------------------------------------------------------- | | `sip_call_id` | String | Complete Call-ID header value. Repeat it on every dialog from the same SIP dialog | | `sip_from_tag` | String | `tag` parameter of the From header | | `sip_to_tag` | String | `tag` parameter of the To header. May be absent if the dialog was never established | | `sip_cseq` | UnsignedInt | Sequence number from the CSeq of the dialog-creating request, as an integer (`314159`, not `"314159 INVITE"`) | ## Attachment purposes Signaling attachments SHOULD carry `purpose`, `start`, `party`, `dialog` and `mediatype` when available (Section 6). Note that core-04 requires `start`, `party` and `dialog` on every attachment; some of the draft's examples leave them out. | `purpose` | Contents | `mediatype` | | -------------------------- | ---------------------------------------------------------------------- | -------------------------------------------------------------- | | `sip-invite` | An INVITE request | `message/sip` | | `sip-response` | A provisional or final response | `message/sip` | | `sip-ack` | An ACK request | `message/sip` | | `sip-bye` | A BYE request | `message/sip` | | `sip-cancel` | A CANCEL request | `message/sip` | | `sip-update` | An UPDATE request (RFC 3311) | `message/sip` | | `sip-refer` | A REFER request (RFC 3515) | `message/sip` | | `sip-message-trace` | The full message sequence as JSON (`version`, `call_id`, `messages[]`) | `application/json` | | `sip-sdp` | An SDP body | `application/sdp` | | `sip-headers` | Selected headers as a JSON object | `application/json` | | `stir-certificate` | The certificate or chain that signed the PASSporT | `application/pkix-cert` or `application/pem-certificate-chain` | | `stir-verification-report` | A STIR verifier's result, including attestation level `A`, `B` or `C` | `application/json` | | `stir-passport-extended` | A PASSporT beyond the compact one in the party's `stir` | `application/passport` | Store whole SIP messages in wire format, with `encoding: "none"` for UTF-8 text or `base64url`. JSON bodies use `encoding: "json"` with the object as the value. ## SIPREC [`vcon-siprec-adapter`](https://github.com/vcon-dev/vcon-siprec-adapter) ([tool page](/tools/vcon-siprec-adapter.md)) receives SIPREC sessions and writes vCons that use this extension. ## See also * [Field reference](/vcons/field-reference.md) for core party and dialog fields. * [Certifying a conversation](/use-cases-studies/patterns.md#certifying-a-conversation) for the STIR/SHAKEN background. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://www.conserver.io/extensions/sip-signaling.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.