How communication works
Cisco TelePresence Movi Administrator Guide (4.1)
Page 18 of 29
How communication works
This section includes general information on Movi's main types of communication and is essential for the
subsequent section, which describes specific messages.
SIP communication
Movi communicates with the Cisco VCS using the Session Initiation Protocol (SIP). Subscribing,
registering, presence querying, call invites—all communication except video and audio, is done in SIP.
SIP messages are sent using TCP, with or without TLS encryption depending on the
Transport
configuration in the
Advanced
settings.
The default SIP listening ports used on the Cisco VCS are
n
5060 (unencrypted)
n
5061 (encrypted)
These are both configurable. Go to
VCS Configurations > Protocols > SIP > Configuration
to
change the listening ports.
Note:
If you change the SIP listening port number on the Cisco VCS, you must also configure the Movi
clients to contact the Cisco VCS on this port. See Advanced settings for more information.
Movi itself will use ephemeral TCP ports for this communication. These ports are handed over to the
Movi client by the TCP stack and are not configurable.
To enable communication with endpoints and other devices that rely on H.323 and do not support SIP,
interworking on the Cisco VCS can be used.
Media communication
Media data is transferred through up to nine UDP links (ports). There are at most five media streams:
n
Audio
n
Primary video
n
Secondary video (presentation sharing)
n
BFCP (management of presentation sharing/duo video, see below)
n
Far end camera control (FECC)
With the exception of BFCP, each of these streams requires two links: one link for RTP packets and one
link for RTCP packets. The SRTP protocol is used if encryption is enabled.
Port ranges
The default port range for Movi to receive media is 21,000-21,900. This range is configurable in Cisco
TMS:
1. Go to
Systems > Provisioning > Directory
.
2. Add (or select) the configuration's Media Port Range Start and Media Port Range End.
Note:
A minimum range of 10 ports must be configured, or Movi will revert to default.
The default port range used on the Cisco VCS is 50,000-52,399. To configure:
