IMG 1010 - Vocoder Entry

Description:

Each VoIP Bearer port can have up to seven individual Codecs configured under it. Once created under the IP Bearer Profiles object, the IMG’s IP signaling stacks will negotiate their use in the order in which they appear in the GUI. The order which the vocoders are negotiated can be modified by selecting one of the vocoder entries and using the Up/Down arrows in the ClientView menu toolbar. The Codec Entry Pane specifies a payload type such as G.729A etc. Maximum, Minimum, and Preferred payload types can be changed through the drop down menu.

Accessing this Pane

Dialogic IMG EMS > IP Bearer Profiles > IP Bearer Profile > Supported Vocoders

Maximum Objects

Up to seven Codec entries per IP Bearer Profile.

Related Topics

IMG 1010 - Overview of VoIP

IMG 1010 - Configuring IP Bearer Profiles

IMG 1010 - Setting Host Flags

IMG 1010 - SIP Codec Negotiation

IMG 1010 - SIP Codec Negotiation Priority Selection

Technical Notes:

When configuring a Supported Vocoder, the following happens:

The Supported Vocoders are added to memory. Once the user clicks on the Save Profiles button in the IP Bearer Profiles object, this data and the data from each of the IP Bearer Profile objects is placed in a table and sent to each of the Logical IMG's.

ClientView Pane:

Field Descriptions:

Entry ID:

This field is automatically populated with the next available ID and specifies the ID of the Codec. To change the ID, click in the Entry ID field and select a different ID from the drop down menu. Up to seven entries can be added to each Bearer Profile object and the ID's range in value from 0-6.

Payload Type:

Select from drop down menu from a list of all the payload types supported by the IMG. Below is a list of the supported Codecs and their payload sizes.

Preferred Payload Size (ms):

The Preferred Payload Size field specifies the desired payload size for the selected Payload Type. The preferred payload size can be changed by using the drop down menu in that field. See Codec/Payload Selection and SIP Codec Negotiation Priority selection in the Related Topics section above for more information on Codec/Payload Size Negotiation

Minimum Payload Size (ms):

The Minimum Payload Size field specifies the minimum payload size for the selected Payload Type. The minimum payload size can be changed by using the drop down menu in that field. See Codec/Payload Selection and SIP Codec Negotiation Priority selection in the Related Topics section above for more information on Codec/Payload Size Negotiation

Maximum Payload Size (ms):

The Maximum Payload Size field specifies the maximum payload size for the selected Payload Type. The maximum payload size can be changed by using the drop down menu in that field. See Codec/Payload Selection and SIP Codec Negotiation Priority selection in the Related Topics section above for more information on Codec/Payload Size Negotiation

Default Payload Type:

If the payload type is static then it must be used. If the payload type is dynamic then it is selectable in ClientView. Below are the Codecs that currently support a dynamic payload type.

Annex B Support: (G.729A and G.729E only)

Annex B Support selection in this menu only applies to how the SIP SDP will use the “annexb=” string during codec negotiation.  This is a SIP-specific parameter.  By the RFC standards 3555/4856, “annexb=” can be used for G.729A and G.729E vocoders to negotiate silence suppression usage (see the following table for all negotiation scenarios), but at the RTP media level “Annex B” defines the silence suppression algorithm for G.729A (hence G.729A/B) while “Annex G” defines the silence suppression algorithm for G.729E (hence G.729E/G).

In this drop down menu, the user can decide how the SIP/SDP “annexb=” string will be utilized. The selections are Annex B=No, Annex B=Yes. This option is currently supported only in G.729A and G.729E, when SIP is the IP signaling protocol. When configuring the G.729A or G.729E codec in ClientView the Annex B field is defaulted to Yes. See Below for more information.

• If the user selects No in the drop down menu then the media attribute Annex B=no is sent by the IMG in the SDP portion of the SIP message when enforcing the use of the G.729 payload type. In this case, the silence suppression algorithm is not added to the G.729A codec.

• If the user selects Yes in the drop down menu then the Annex-B message will not be displayed in the SDP portion of the SIP message. This value is implied when unspecified in the SDP. In this case, the silence suppression algorithm is added to the G.729A codec.

• If G.729 Codec is not being used then ClientView will disable the Annex B support field and it will not be visible.

Annex B Ingress: (10.5.3 SP4)

When configuring G.729A or G.729E codec the manner in which the Annex B Parameter is handled has been redesigned to allow for many different Annex B negotiation behaviors. Starting in software version 10.5.3 SP4 a field labeled Annex B Ingress was added to allow for the selection of several possible behaviors. When G.729A or G.729E is selected, the Annex B and Annex B Ingress field will be opened. Use the table below to select how SDP negotiation will behave.

 Table below displays all possible combinations of Annex B support.