Service Providers
Polycom, Inc.
38
device allows as long as 5 seconds to wait for the response from all the candidates, and selects the highest
priority candidate that has a response. Once ICE completes successfully, the device further applies
symmetric RTP to determine the peer’s RTP address (that is, sends them to the address from which the
peer’s RTP packets are coming).
ITSP Driven Distinctive Ringing
The device offers 10 ring and 10 call-waiting tone patterns in each ring profile. These patterns are numbered
from 1 to 10. Each pattern also comes with a configurable name. You can assign a different default ring to
each trunk on the device.
An ITSP can tell the device which ring to use by name for a call routed to SP1/SP2 by inserting an Alert-Info
header in the SIP INVITE sent to the device. The Alert-Info must include a URI. For example:
Alert-Info:
http://www.xyz.com/some-folder/bellcore-dr4
When the device receives this, it looks for a ring tone name or call-waiting tone name in the ring profile that
matches the Alert-Info URI. Ring tone names are not case sensitive. If a match is found, the device plays
the corresponding ring or call-waiting tone. Otherwise, the device plays the default ring.
RTP Statistics – the X-RTP-Stat Header
When ending an established call, the device can include a summary of the RTP statistics collected during
the call in the SIP BYE request or the 200 response to the SIP BYE request sent by the peer device. The
summary is carried in an X-RTP-Stat header in the form of a comma-separated list of fields. The reported
fields are:
●
PS
= Number of Packets Sent
●
PR
= Number of Packets Received
●
OS
= Number of bytes sent
●
OR
= Number of bytes received
●
PL
= Number of packets lost
●
JI
= Jitter in milliseconds
●
LA
= Decode latency or jitter buffer size in milliseconds
●
DU
= Call duration in seconds
●
EN
= Last Encoder Used
●
DE
= Last Decoder Used
For example:
X-RTP-Stat:PS=1234,OS=34560,PR=1236,OR=24720,JI=1,DU=1230,PL=0,EN=G711U, DE=G711U
To enable the X-RTP-Stat feature, set the
ITSP Profile X – SIP
::X_InsertRTPStats
parameter to YES (or
TRUE).
Media Loopback Service
The device supports the media loopback draft as described in
draft-mmusic-media-loopback-13.txt
. The
device supports the following media loopback features:
●
Loopback modes:
loopback-source
and
loopback-mirror
