Obihai OBi110, Administration Manual

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Copyright 2010-2012 Obihai Technology, Inc. 90
RTP Statistics – the X-RTP-Stat Header
When ending an established call, OBi 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, the parameter ITSP Profile X – SIP::X_InsertRTPStats must be set to YES (or TRUE).
Media Loopback Service
The OBi supports the media loopback draft as described in draft-mmusic-media-loopback-13.txt . The following media
loopback features are supported by the OBi device:
- Loopback modes: loopback-source and loopback-mirror
- Loopback types: rtp-media-loopback and rtp-packet-loopback
- Loopback packet formats:: encaprtp, loopbkprimer
When acts as a loopback mirror, OBi device always sends primer packets so that incoming packets can get through
NAT/Firewall. The media loopback feature is controlled by the following parameters (under PHONE Port – Calling Features
section):
- AcceptMediaLoopback – Enable device to accept incoming call that requests media loopback. Default is YES.
- MediaLoopbackAnswerDelay – The delay in millis before the OBi answers a media loopback call. Default is 0.
- MediaLoopbackMaxDuration – The maximum duration to allow for an incoming media loopback call. Default is 0,
which means the duration is unlimited.
Note that the device will reject incoming media loopback call if:
- PHONE port is off hook.
- PHONE port is ringing.
- PHONE port is onhook with a call on hold.
Device will terminate an inbound media loopback call already in progress when:
- PHONE port is off-hook.
- PHONE port is ringing.
To make an outgoing loopback call, user can dial one of the following star codes before dialing the target number:
- *03 – Make a Media Loopback Call.
- *04 – Make a RTP Packet Loopback Call.
Note that outbound Media Loopback Call is not subjected to call duration limit; it will last until the user hangs up or until
the called device ends the call.