AltiGen MAXCS 7.0 Update 1 ACM Administration - Manual (Page 330)

Setting VoIP Codec Profiles
314 MaxCS 7.5 Administration Manual
SIP Transport
There are several SIP Transport options. Note that security options
TLS and SRTP can be configured for individual IP phone extensions
in the IP Phone Configuration screen. (For more information on
security settings, see “SIP Transport” on page 214.) Extension-level
configuration takes precedence over a codec profile that is assigned
in Enterprise Manager. See the next section.
UDP
– User Datagram Protocol is a communications protocol that
offers a limited amount of service when messages are exchanged
between computers in a network that uses the Internet Protocol (IP).
Note:
All SIP trunks must use UDP.
TCP – Transmission Control Protocol is a set of rules (protocol) used
along with the Internet Protocol (IP) to send data in the form of
message units between computers over the Internet. TCP is known
as a connection-oriented protocol, which means that a connection is
established and maintained until such time as the message or
messages to be exchanged by the application programs at each end
have been exchanged. TCP is responsible for ensuring that a
message is divided into the packets that IP manages and for
reassembling the packets back into the complete message at the
other end.
Note:
AltiGen phones do not use TCP.
SIP Transport
TLS – Secures SIP signaling messages using Transport Layer
Security. (Does not work for IP devices behind NAT; UDP will be
used, instead.)
TLS/SRTP
– Adds Secure RTP to Transport Layer Security to secure
SIP-associated media. (Does not work for IP devices behind NAT;
UDP will be used, instead.) (If this option is chosen, the voice stream
always goes through the server.)
Persistent TLS/SRTP
– Persistent TLS/SRTP for SIP signaling
messages.
Codec Parameter Description