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Port 0 rejects a stream

Port 0 refuses the stream in that slot. The m-line stays, with a protocol and a format list.

Learn in 5 minutes

  1. Write a rejection as port 0
  2. Keep the rejected line in order
  3. Refuse a stream that has no codec in common

Visual

Second stream refused · study drawing · cyphermonkeylabs.com AliceCarrier INVITE 100 200 ACK

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The second stream is unused. It is still the second m-line.

Worked example

See a zero port Negotiate an offer of two audio lines. The answer accepts the first and zeros the second.

  1. Press Negotiate.
  2. Read m-line 1.
  3. Read the port on m-line 2.

Fault

A re-INVITE offers m=audio 0 RTP/AVP 8 in the second slot. The peer answers m=audio 40002 RTP/AVP 8 and media appears on a stream that was supposed to be gone.

RFC 3264 requires a zero offer port to be rejected.

Quiz

Which answer port rejects a stream?


A rejected m-line still includes


No shared codec on one m-line means


An offer that already uses port 0


Appending a new stream


Removing a rejected line from the answer


Ecosystem

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

CRM Screen pop uses data the contact center already has: ANI, DNIS, case id. Those values may arrive in SIP headers or in a CTI event after the call is up. The CRM is not a SIP element.

Glossary · Ecosystem map · Ports · Troubleshooting

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