SIP Distributed Media Release

This section explains how to configure distributed media release (DMR). SIP DMR lets you choose whether to include multi-system (multiple Oracle® Enterprise Session Border Controllers) media release information in SIP signaling requests sent into a specific realm.

Overview

The SIP DMR feature lets RTP/RTCP media be sent directly between SIP endpoints (for example, SIP phones or user agents) without going through a Oracle® Enterprise Session Border Controller; even if the SIP signaling messages traverse multiple Oracle® Enterprise Session Border Controllers. It encodes IPv4 address and port information for the media streams described by the media, for example SDP.

With SIP DMR, the media realm and IPv4 address and port information from the UA's SDP is encoded into SIP messages (either in the SIP header or in the SDP) as they enter the backbone network. The information is decoded by a Oracle® Enterprise Session Border Controller from SIP messages that come from the backbone network. The decoded address and port information is put into the SDP sent the UAs in the access (private/customer) network.

This functionality lets the RTP/RTCP flow directly between the UAs in the access network without traversing the Oracle® Enterprise Session Border Controllers and without passing into the backbone network. The media can then flow directly between the two SIP endpoints in the same network, if it is serviced by multiple Oracle® Enterprise Session Border Controllers.

You can enable this feature on a per-realm basis and multiple realms can be supported.

Endpoint Locations

You can configure the Oracle® Enterprise Session Border Controller to release media when the source and destination of the call are in the same network, customer VPN, or customer LAN. In architectures that use DMR, the Oracle® Enterprise Session Border Controller is only part of the media path for traffic that originates and terminates in different networks.

If configured to do so, the Oracle® Enterprise Session Border Controller can release media:

Between endpoints supported by a single Oracle® Enterprise Session Border Controller
In the same network/VPN

In the same network behind the same NAT/firewall
Between endpoints supported by multiple distributed Oracle® Enterprise Session Border Controllers
In the same network/VPN

Location of the Encoded Information

Encoded media release information can appear in three different places:

SDP attribute
Media release data can be encoded into an SDP attribute in the SIP message body (for example, media-release=sdp;acme-media). The encoded data is placed into an acme-media attribute in the SDP:
```
a=acme-media:<encoded-media-interface-info>
```
SIP header parameter
Media release data can be placed in a header parameter of a SIP header (for example, media-release=Contact;acme-media). The encoded data is placed into an acme-media parameter in the Contact header:
```
Contact: <sip:1234@abc.com>;acme-media=<encoded-media-interface-info>
```
SIP header
Media release data can appear in a SIP header (for example, media-release=P-Media-Release). The encoded data is placed into a P-Media-Release header:
```
P-Media-Release: <encoded-media-interface-info>
```

Example Distributed Media Release

The following example shows the network diagram for DMR in a multiple-site VPN environment supported by multiple, distributed Oracle® Enterprise Session Border Controllers.

The Example Distributed Media Release diagram is described below.

As shown in the network diagram, UA A and UA B register with the softswitch through Oracle® Enterprise Session Border Controller A while UA C and UA D register with the softswitch through Oracle® Enterprise Session Border Controller B. Without DMR, the media for calls between UA A/UA B and UA C/UA D is steered through both Oracle® Enterprise Session Border Controller A and Oracle® Enterprise Session Border Controller B.

With SIP DMR, the media realm and IPv4 address and port information from the UA's Session Description Protocol (SDP) is encoded into SIP messages (either in the SIP header or in the SDP) as they enter the backbone (public/service provider) network. The information is decoded from SIP messages that come from the backbone network. The decoded address and port information is put into the SDP sent to the UAs in the access (private/customer) network. This functionality allows for the RTP/RTCP to flow directly between the UAs in the access network without traversing the Oracle® Enterprise Session Border Controllers and without passing into the backbone network.

Overview of SIP DMR Configuration

To configure SIP DMR:

Edit the SIP config element’s option field.

The media-release=”<header-name>[;<header-param>]” option defines how the SIP distributed media release feature encodes IPv4 address and port information. If the media-release parameter is configured in the options field but no header is specified, the parameter value of P=Media-Release will be used. This parameter is optional and is not configured by default.
Enable SIP DMR for the entire realm by setting the realm config element’s msm release field to enabled.

The media IPv4 address and port information is encoded into outgoing SIP messages and decoded from incoming SIP messages for all of the realms (in each realm-config element) with which the SIP distributed media release will be used.

Note:
You can also use the realm config element’s mm in network field to release the media back to a connected network that has multiple realms. This field is not specific SIP distributed media release and it is not required for the SIP DMR to work. However, if this field is set to enabled and the ingress and egress realms are part of the same network interface, it lets the Oracle® Enterprise Session Border Controller release the media.

SIP DMR Configuration

To configure media release:

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
```
Type session-router and press Enter to access the system-level configuration elements.
```
ORACLE(configure)# session-router
```
Type sip-config and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.
```
ORACLE(session-router)# sip-config
ORACLE(sip-config)#
```
From this point, you can configure SIP config parameters. To view all SIP config parameters, enter a ? at the system prompt.
Type options followed by a Space.
After the Space, type the media release information in the following format:
```
media-release=”<header-name>[;<header-param>]”
```
- header-name either refers to the SIP header in which to put the information or to the special header-name value of sdp to indicate the information should be put into the SDP.
- parameter-name refers to the header parameter name in which to put the information or, in the case of the special header-name value of sdp, to the SDP attribute name in which to put the information.
  
  For example:
```
ORACLE(sip-config)# options media-release=P-Media-Release
```
Press Enter.
Note:
If the media-release parameter is configured in the options field, but no header is specified, then the parameter value of P-Media-Release will be used. P-Media-Release is a proprietary header and means that the media will be encoded in the SIP header with this name.

The following example shows where the encoded information (for example, SDP data) is passed.
```
media-release=”P-Media-Release”
media-release=”Contact;acme-media”
media-release=”sdp;acme-media”
```

Configuring the Realm

You need to set the each realm config element’s msm release field to enabled for all the realms for which you want to use SIP DMR.

Although the mm in network field is not specific to the SIP distributed media release feature, it can be used to release the media back to a connected network that has multiple realms. This field does not need to be configured in order for the SIP distributed media release feature to work. However, if this field is set to enabled and the ingress and egress realms are part of the same network interface, it lets the Oracle® Enterprise Session Border Controller release the media.

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
```
Type media-manager and press Enter to access the media-related configurations.
```
ORACLE(configure)# media-manager
```
Type realm and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.
```
ORACLE(media-manager)# realm-config
ORACLE(realm-config)#
```
From this point, you can configure realm parameters. To view all realm configuration parameters, enter a ? at the system prompt.
msm-release—Enable DMR within this realm on this Oracle® Enterprise Session Border Controller. The default value is disabled. The valid values are:
- enabled | disabled
Repeat for each realm on which you want to enable DMR.