Multimedia Call Routing

The H.223 and H.245 protocols are used to establish multimedia calls between endpoints over circuit switched networks. These protocols come into play after successful call completion between the multimedia endpoints. The initial SS7/ISDN call setup messages contain an octet that indicate that the call will utilize H.223/H.245. Multimedia Call Routing supports routing calls based on the presence of this specific octet. Thus with this feature, routing is configured using the new routing criteria type Multimedia Call.

The feature will make use of the existing IMG 2020 routing capability. The analysis in this document will identify the relevant bit values and their locations within initial call setup messages that identify a call as a multimedia call.  It will describe the routing criteria that the IMG 2020 needs to set in the route entries when this feature is selected in the configuration. The route action rule portion in the route entry remains the same as for the other existing route options. That is, once the multimedia call is identified and matched with the route entry, the action of routing is the same as for other configurable call criteria. Note that having committed the Multimedia Call criteria a total of six route table entries are sent to the switch.

Indication

For SS7, the User Information Layer 1 Protocol parameter forms part of the User Service Information IE which, when set as Recommendation H.223 & H.245 along with Layer 1 Identity and extension bit gives the octet a hex value of 0xa6. This parameter may appear in different locations within the information element due to the presence of other octets.  The User Information Layer 1 Protocol parameter may also be presented in the Low Layer Compatibility IE as part of the Access Transport IE in which, again the User Information Layer 1 Protocol parameter may be presented in different locations within the information element due to the presence of other octets and other information elements.

For ISDN the  User Information Layer 1 Protocol parameter forms part of the Bearer Capability IE or part of the Low Layer Compatibility IE.  Again, the User Information Layer 1 Protocol parameter may be presented in different locations within the Information Elements due to the presence of other octets.

The IMG 2020 will scan the incoming initial message for the Recommendation H.223 & H.245 value of the User Information Layer 1 Protocol where ever it is located and will route the call on this criteria

User Information Layer 1 protocol

The value highlighted in above table will be set in the routing criteria in the route table entries.

Below is table displaying the format of the User Service Information/Bearer Capability IE.

Below is table displaying the format of the Low Layer Compatibility IE.

The format of this IE can change based on values in each of the octets. For example, octet 2a is required if octet 2 indicates multirate(64 kbit/s base rate); otherwise it shall not be present. For this reason there can be multiple locations for the User Information Layer 1 protocol parameter coming from ISDN/SS7. For the IMG 2020 to route on a Multimedia call, it must be able to match on the required parameters to specify the H.223/H.245. The possible combinations are displayed below.

Option 1: Routing Criteria for User Information Layer 1 Protocol in User Service Info IE with no Rate Multiplier octet 

Option 1: Routing Criteria for User Information Layer 1 Protocol in User Service Info IE with Rate Multiplier octet

Option 2: Routing Criteria for User Information Layer 1 Protocol in Low Layer Compatibility IE with Negotiation Indicator/Spare and Rate Multiplier octets

Option 3: Routing Criteria for User Information Layer 1 Protocol in Low Layer Compatibility IE with Negotiation Indicator/Spare octet and with no Rate Multiplier octet

Option 4: Routing Criteria for User Information Layer 1 Protocol in Low Layer Compatibility IE with no Negotiation Indicator/Spare octet and with Rate Multiplier octet

Option 5: Routing Criteria for User Information Layer 1 Protocol in Low Layer Compatibility IE with no Negotiation Indicator/Spare octet and no Rate Multiplier octet.

Configuration

Below are instructions on how to configure the IMG 2020 to route calls dependant on whether call is categorized as multimedia. Before proceeding with the instructions below, verify that the following functionality has been initially configured on the IMG 2020.

• Basic Configurations. Configures initial functionality such as Profiles, DS-1's/DS-0's, IP spans, and interfaces.

• Configure SS7. Configures SS7 stacks, links, linksets, etc. Configuring SS7

The procedure below will start from the Routing Configuration Pane within the Web GUI. The following configuration example will demonstrate the configuration needed to accept a call coming from an SS7 Network and route it based on the routing criteria Multimedia Calls.  

Create Channel Groups

The first step would be to create an SS7 Channel Group. The SS7 Channel Group would receive an incoming call from the PSTN and route the call to a Route Table which would then send call to a Route Table Entry.

Create SS7 Channel Group

• Right click on the Dialogic object and select New Routing Configuration. The Routing Configuration object is a parent or container object and no configuration is needed here. Refer to the Routing Configuration topic for more information on this object.

• Right click on Routing Configuration and select New Channel Groups. The Channel Groups object is a parent or container object and no configuration is needed here. Refer to the Channel Groups topic for more information on this object.

• Right click on the Channel Groups object and select New Channel Group. A Channel Group object will appear. Either enter a Name that identifies this channel group or accept the default name already entered.

• Select SS7_ISUP from drop down menu in the Signaling Type field. Refer to the Channel Group topic for more information on configuring the SS7 Channel Group.

• Right click on the Channel Group object created and select New Circuit Group. Select from the drop down menus the Node that the CICs will reside on as well as the Starting and Ending DS-1/DS-0 that the CICs will be configured on. Create as many CIC or Circuit Groups needed.

Create SIP Channel Group

• Right click on the Channel Groups Object and select New Channel Group. A Channel Group Object will appear. Either enter a name that identifies this channel group or accept the default name entry.

• Set the Signaling Type field to SIP. The Incoming Channel Group in this example will be a SIP Channel Group and be named ChGrp_SIP. Refer to the Channel Group topic for more information on configuring the individual fields.

• Once the Channel Group configuration has been achieved, click back onto the Channel Groups object. This object will now display an exclamation point in the icon indicating the configuration has not been sent to the IMG 2020. Click on the Download Resource Tables button and the configuration will be sent to the IMG 2020.

Create Route Tables and then Route Table Entries

The routing for this feature will now be accomplished. The next few steps will configure the objects needed to route the call.

Create Route Table and Route Table Entry

• Right click on the Routing Configuration object and select New Routing Tables. The Routing Tables object created is a container object which will allow multiple individual Routing Tables to be created beneath it. Refer to the Routing Tables topic for more information.

• Right click on Routing Tables and select New Table. A Route Table object will get created. Either accept the default name in the Name field or enter a name that identifies this Route Table. In this example the name will be RouteTable1. Click on the entry Multimedia Call in the Routing Criteria Order field and move it to the uppermost position. See screen capture below. This will give Multimedia calls the highest priority. Refer to the Route Table for more information on configuring the Route Table Object.

Open

• Create a Route Entry under the Route Table by right clicking on Route Table and select New Entry. A Route Entry screen will appear. Click in the Routing Criteria Type field and a drop down menu appears. Select Multimedia Call from the list. Refer to screen capture below.

• In the Outgoing Channel Group field of the Route Entry object select which channel group to send call out on. In this example, the SIP Channel group was selected. Refer to screen capture below.

Open

• Finish configuring the Route Entry. Refer to the Route Table Element topic for more information on this object.

• Once the Route Table and Route Entry's has been configured, click back onto the Route Table object. This object will now display an exclamation point in the icon indicating the configuration has not been sent to the IMG 2020. Click on the Download Routing Table button and the configuration will be sent to the IMG 2020.

Configure Channel Group to access Route Table configured

• Once the Route Table and Route Entry are configured, go back to the incoming Channel Group created. Select the Route Table configured above from the drop down menu in the Route Table field. By selecting the Route Table, the rejected call with the Cause Code configured will be sent out this Channel Group. See Below.

• Click on the Channel Groups object again. Click on the Download Resource Tables button and the updated Channel Group configuration will be sent to the IMG 2020.

Additional Information

• When Multimedia Calls is selected as the routing criteria type, six separate route entries are sent to the IMG 2020 . The standard is to have one route entry sent for each route entry created. Since six route entries are sent when Multimedia is selected, this will reduce the number of total entries supported in IMG 2020 by six.

• Of the six entries sent, each entry will have a different routing criteria as displayed in the six options above.

• The Web GUI supports creating one Multimedia Call object per Route Table.