System information

Configuring the Voice Settings
PSTN (LINE Port)
Cisco SPA232D Administration Guide 119
4
SIP Settings
RTP ToS/DiffServ
Value
ToS/DiffServ field value in UDP IP packets carrying RTP
data.
Default setting: 0xb8
RTP CoS Value CoS value for RTP data. Valid values are 1 through 7.
Default setting: 6
Network Jitter
Level
Determines how jitter buffer size is adjusted by the ATA
device. 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: low
Jitter Buffer
Adjustment
Controls how the jitter buffer should be adjusted. Select
the appropriate setting: up and down, up only, down only,
or disable.
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.
O p t i o n s a r e : U D P, T C P, T L S . T h e d e f a u l t i s U D P.
Default setting: UDP
SIP Port Port number of the SIP message listening and
transmission port.
Default setting: 5060
Field Description