User`s manual

SIP User's Manual 5. Web Management
Version 5.0 109 December 2006
¾ To configure the coder group settings, take these 11 steps:
1. Open the ‘Coder Group Settings’ screen (Protocol Management menu > Profile
Definitions submenu > Coder Group Settings option); the ‘Coder Group Settings’
screen is displayed.
Figure 5-22: Coder Group Settings Screen
2. From the 'Coder Group ID' drop-down list, select the coder group you want to edit (up
to four coder groups can be configured).
3. From the 'Coder Name' drop-down list, select the coder you want to use. For the full
list of available coders and their corresponding attributes, refer to Table 5-5.
4. From the 'Packetization Time' drop-down list, select the packetization time (in msec)
for the coder you selected. The packetization time determines how many coder
payloads are combined into a single RTP packet. The ptime specifies the
packetization time the gateway expects to receive. The gateway always uses the
ptime requested by the remote side for sending RTP packets.
5. From the 'Rate' drop-down list, select the bit rate (in kbps) for the coder you selected.
6. In the 'Payload Type' field, if the payload type for the coder you selected is dynamic,
enter a value from 0 to 120 (payload types of ‘well-known’ coders cannot be modified).
The payload type identifies the format of the RTP payload.
7. From the 'Silence Suppression' drop-down list, enable or disable the silence
suppression option for the coder you selected.
8. Repeat steps 3 to 7 for the second to fifth coders (optional).
9. Repeat steps 2 to 8 for the second to fourth coder groups (optional).
10. Click the Submit button to save your changes.
11. To save the changes so they are available after a power fail, refer to Section 5.10.2 on
page 205.
Notes:
• Each coder can appear only once.
• If not specified, the ptime gets a default value. The ptime specifies
the packetization time the gateway expects to receive. The gateway
always uses the ptime requested by the remote side for sending
RTP packets.
• If payload type is not specified, a default is used.
• For G.729 it is also possible to select silence suppression without
adaptations
• Only the ptime of the first coder in the defined coder list is declared
in INVITE / 200 OK SDP, even if multiple coders are defined.
• If coder G.729 is selected and silence suppression disabled, the
gateway includes the string ‘annexb=no’ in the SDP of the relevant
SIP messages. If silence suppression is enabled or set to ‘Enable
w/o Adaptations’, ‘annexb=yes’ is included. An exception to this logic
is when the remote gateway is a Cisco device (IsCiscoSCEMode).