Codec Policy Configuration
When configuring transcoding, you must create a codec policy and associate the policy to a realm.
In the codec policy, you specify:
- Which codecs to allow and which codecs to deny within a realm.
- Which codecs to add to the SDP m= lines for an egress realm.
- The preferred order of codecs shown in an SDP m= line.
- The packetization time to enforce within a realm for transrating.
ACLI Configuration Instructions
The parameters that you can configure are name, allow-codecs, add-codecs-on-egress, order-codecs, and ptime. The following section provides brief explanations of how these parameters work, and how you configure each of them.
Note:
A single codec policy can be reused for any number of realms.To access the configuration parameters for codec policies:
Naming Codec Policies
The codec policy’s name is important not only because it uniquely identifies the policy, but because it is the name you will enter into your realm configuration’s codec-policy parameter. It is important to apply the correct policy to the appropriate realm.
To set the codec policy’s name:
Removing Allowing and Adding Codecs
The Oracle® Enterprise Session Border Controller removes and allows codecs using the allow-codecs parameter. Refer to the Codec Policy Definition section of this chapter for configuration information.
- allow-codecs—The allow-codecs parameter takes a list of codecs that you want to pass through the Oracle® Enterprise Session Border Controller and can explicitly allow them to remain in the SDP for the next step; codecs not matching the items on this list are removed. This parameter is required.
- add-codecs-on-egress—The
add-codecs-on-egress parameter sets the codecs that the
Oracle® Enterprise Session Border Controller adds to an offer if that codec is not already there. This parameter applies only to the egress policy.
For allow-codecs, order-codecs, and add codecs to codec policies:
You can configure and edit these two transcoding parameters as ACLI lists, meaning that there are add and delete commands associated with each. You type the name of the parameter, choose the operation you want to perform on the list (adding or deleting), and then specify the data that you want to add or remove.
The examples in the procedure that follows show you how to add to the lists you are configuring. To remove items from the allow-codecs list, simply replace the add command you see in these example with delete and the items you want to remove.
If you want to overwrite previous values, you can enter the command, a Space and the items in the list enclosed in quotes (“).
Ordering Codecs
Codec policy can specify the order that codecs appear in the SDP offer or answer.
To configure an order which codecs appear in the offer:
Transrating Configuration
The following procedure explains how to configure transrating for a codec policy. This codec policy must be applied as an egress codec policy.
To configure forced ptime for a codec policy:
Applying a Codec Policy to a Realm
Once you have configured a codec policy, you apply it to a realm by configuration name.
To apply a codec policy to a realm:
Secure DTMF Cancellation
For security and privacy reasons, you can remove all Dual-Tone Multi-Frequency (DTMF) information that the
Oracle® Enterprise Session Border Controller (E-SBC) processes by enabling
secure-dtmf-cancellation within the codec-policy. For example, you might want to cancel all DTMF tones when processing credit card numbers, debit card numbers, PIN numbers, and other DTMF-based passwords that you want to remove from the media stream. When an incoming call requires DTMF cancellation, the
E-SBC uses the built-in detection and cancellation mechanism to completely remove all sixteen DTMF tones on ingress making the tones undetectable on egress. (0-9, *, #, A,B,C,D)
In contrast to standard DTMF cancellation, which leaves some residual signal energy at the beginning and ending of each DTMF digit,
secure-dtmf-cancellation removes all signal energy from the media stream by adding an extra 10μs to the leading and trailing edges of the DTMF tones. The result is silence for the entire duration of each DTMF digit because the system mutes all audio when you suppress DTMF tones with
secure-dtmf-cancellation.
- PCMU
- PCMA
- G.726-32 (and higher)
- G.722
Secure DTMF cancellation supports hardware transcoding only. You must own the transcoding license and you need transcoding resources, such as a Digital Signal Processor (DSP). In addition to enabling
secure-dtmf-cancellation in the codec policy, you must enable
dtmf-in-audio in the codec policy. You can enable
secure-dtmf-cancellation and
dtmf-in-audio in the ACLI and the Web GUI.
Note:
An endpoint configured as secure at the session startup stays in the secure mode throughout the call because you cannot re-configure the DTMF cancellation mode during the call.Enable Secure DTMF Cancellation
When you want to completely remove all traces of Dual-Tone Multi-Frequency (DTMF) information that the Oracle® Enterprise Session Border Controller (E-SBC) processes, enable secure-dtmf-cancellation to make the DTMF tones undetectable.
Secure-dtmf-cancellation requires that you also enable dtmf-in-audio. If dtmf-in-audio is not already enabled, you can enable both attributes in the following procedure.
