System information

Configuring Voice
Configuring Voice Settings
Cisco SPA100 Series Phone Adapters Administration Guide 91
4
SIP Settings
Network Jitter Level Determines how jitter buffer size is adjusted by
the ATA. Jitter buffer size is adjusted dynamically.
The minimum jitter buffer size is 30 milliseconds
or (10 milliseconds + current RTP frame size),
whichever is larger, for all jitter level settings.
However, the starting jitter buffer size value is
larger for higher jitter levels. This setting controls
the rate at which the jitter buffer size is adjusted
to reach the minimum. Select the appropriate
setting: low, medium, high, very high, or
extremely high. Default setting: high.
Jitter Buffer Adjustment Choose yes to enable or no to disable this
feature. Default setting: yes
Field Description
SIP Transport The TCP choice provides “guaranteed delivery”,
which assures that lost packets are
retransmitted. TCP also guarantees that the SIP
packages are received in the same order that
they were sent. As a result, TCP overcomes the
main disadvantages of UDP. In addition, for
security reasons, most corporate firewalls block
UDP ports. With TCP, new ports do not need to
be opened or packets dropped, because TCP is
already in use for basic activities such as Internet
browsing or e-commerce. Options are: UDP, TCP,
TLS. Default setting: UDP.
SIP Port Port number of the SIP message listening and
transmission port. Default setting: 5060.
SIP 100REL Enable To enable the support of 100REL SIP extension
for reliable transmission of provisional responses
(18x) and use of PRACK requests, select yes.
Otherwise, select no. Default setting: no.
EXT SIP Port The external SIP port number.
Field Description