Cisco SPA301 Administration Manual page 39

Getting Started
Ensuring Voice Quality
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide
—Multi-Party Calls: When there is multi-party conference call, the report is sent for
the session between the reporting endpoint and each remote endpoint for which
there was an RTP session during the call.
—Multi-Segment Calls (Call hold and Call transfer): For a call hold, no SIP PUBLISH
is sent out, but during call transfer as there is session termination, SIP PUBLISH will
be sent out.
—Call termination: If a call is terminated before the first RTCP-XR packet is sent
out, SIP PUBLISH will be sent for session termination with some parameters
retrieved from RTCP-XR filled with default values.
The Cisco SPA IP phones resend the SIP PUBLISH messages with the voice
quality report once per 5xx response with a valid Retry-After header.
A valid time value in seconds is a positive integer from 0 to 65536. A SIP message
with a Retry-After time value of 0 is treated as a 500 Server Internal Error
message. A time value less than 0 is ignored.
The following is a summary of the 5xx messages with Retry-After header that the
phone supports:
5xx SIP Response
500 Server Internal Error
503 Service Unavailable
Description
An unexpected server condition prevents the
fulfillment of request.
The server is unavailable due to a temporary
overload or maintenance.
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