SUBSCRIBE_ERROR

A publisher sends a SUBSCRIBE_ERROR control message in response to a failed SUBSCRIBE.

SUBSCRIBE_ERROR Message {
  Type (i) = 0x5,
  Length (i),
  Request ID (i),
  Error Code (i),
  Error Reason (Reason Phrase),
  Track Alias (i),
}

• Request ID: The Request ID of the SUBSCRIBE this message is replying to Section 8.7.

• Error Code: Identifies an integer error code for subscription failure.

• Error Reason: Provides the reason for subscription error. See Section 1.3.3.

• Track Alias: When Error Code is 'Retry Track Alias', the subscriber SHOULD re-issue the SUBSCRIBE with this Track Alias instead. If this Track Alias is already in use, the subscriber MUST close the connection with a Duplicate Track Alias error (Section 3.4).

The application SHOULD use a relevant error code in SUBSCRIBE_ERROR, as defined below:

• Internal Error - An implementation specific or generic error occurred.

• Unauthorized - The subscriber is not authorized to subscribe to the given track.

• Timeout - The subscription could not be completed before an implementation specific timeout. For example, a relay could not establish an upstream subscription within the timeout.

• Not Supported - The endpoint does not support the SUBSCRIBE method.

• Track Does Not Exist - The requested track is not available at the publisher.

• Invalid Range - The end of the SUBSCRIBE range is earlier than the beginning, or the end of the range has already been published.

• Retry Track Alias - The publisher requires the subscriber to use the given Track Alias when subscribing.

• Malformed Auth Token - Invalid Auth Token serialization during registration (see Section 8.2.1.1).

• Unknown Auth Token Alias - Authorization Token refers to an alias that is not registered (see Section 8.2.1.1).

• Expired Auth Token - Authorization token has expired Section 8.2.1.1).