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RFC 7118: the sip subprotocol

The handshake must offer sip. Via uses WS or WSS. The URI transport parameter added by the RFC is ws.

Learn in 5 minutes

  1. Read Sec-WebSocket-Protocol: sip
  2. Tell Via WSS from a Contact transport=ws
  3. Say why a browser example uses a .invalid host

Visual

Register on WSS, with the example's .invalid host · study drawing · cyphermonkeylabs.com BrowserRegistrar GET 101 REGISTER 200

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These are the names the RFC adds. They are not new SIP methods.

Worked example

Read the REGISTER This synthetic REGISTER uses a .invalid host, Via WSS, and transport=ws. It is a study message, not a copy of the RFC example.

  1. Open the dissector.
  2. Find the Via transport.
  3. Find the Contact transport parameter.

Fault

The Request-URI is sips. The browser opened ws:// on port 80. The registrar accepts the socket.

Section 9.2 requires a secure WebSocket when the sips path uses one.

Quiz

Sec-WebSocket-Protocol must include


Via over a TLS WebSocket uses


The URI transport parameter RFC 7118 adds is


A SIP WebSocket client must implement UDP and TCP


The section 8 registration example uses .invalid because


A sips path that includes WebSocket


Ecosystem

Glossary, sister systems, and the integration seam for this room.

Quality management and recording QM scores interactions. The standardized way an SBC forks a session to a recorder is SIPREC.

Glossary · Ecosystem map · Ports · Troubleshooting

Sources and go deeper