User's Manual

Configuration Description Expected result Possible results
of time before attempting
to reconnect.
IP Deskphone:
UDP + TCP + TLS
Server: UDP + TCP
+ TLS
The IP Deskphone
attempts to contact
the server using
TLS first, because
TLS has higher
priority than TCP
and UDP.
The IP
Deskphone
registers
the same
as if it was
configured for TLS
only.
If the IP Deskphone is
unable to connect to the
server using TLS, it
attempts to connect using
TCP. If attempts to
connect using TLS and
TCP fail, the IP Deskphone
attempts to connect using
UDP. If attempts using
TLS, TCP, and UDP fail,
the IP Deskphone waits a
configured period of time
before attempting to
reconnect.
None: unsupported Unsupported Unsupported Unsupported
Note:
The server must be configured with the appropriate protocols enabled for the success
condition to be realized. Failure results are possible if the server configuration is changed
to disallow protocols.
Managing connection persistence
The IP Deskphone attempts to establish and maintain a persistent connection with the proxy
when
TCP and TLS are active protocols. After this connection is established, the IP Deskphone
sends all outgoing connections over this persistent connection.
SIP IP Deskphones and servers, which use UDP to communicate, listen for incoming
connections on known ports, and originate each request on a randomly selected UDP port.
Even if TCP is used, new requests can potentially be sent using a new source port unless the
connection between the IP Deskphone and proxy is kept active.
Connection persistence does the following:
• Keeps a connection established between a client and the outgoing proxy.
• Reuses the open connection for future incoming and outgoing requests.
TCP/TLS operation overview
SIP Software for Avaya 1200 Series IP Deskphones-Administration September 2013 283