Overview:

The IMG already supports receiving 3xx Redirection messages. Feature 1442 will add the ability to initiate a SIP Redirect by sending a 302 message back to the originating gateway with information of other IMG's in the route list or route table that the originating gateway can send the invite message to.

 

Related Topics:

SIP Redirect IMG Initiated 302 - Example

 

SIP Redirect Diagram:

 

DG_IMG_SIP_Redirect10.5.1.png

 

 

Before the Redirect feature was added a call came in on SIP GhGrp1 above and the TDM resources on that IMG were all busy then the IMG would send out a 486 Busy Here message and the call would be dropped. With the SIP Redirect feature the call will get passed on to the second and third IMG. SIP Redirect is in response to an INVITE message from a SIP Gateway. The Originating Gateway sends an INVITE message to IMG 0. The call signaling then gets passed to the TDM side. If for some reason IMG 0 has all its TDM resources being utilized, IMG 0 will send a 302 response back to the originating gateway with contact information to IMG 1 and IMG 2. The Originating Gateway will then send an INVITE message to IMG 1 and the signaling will get passed to the TDM side. If all TDM resources on IMG 1 are being utilized then IMG 1 will send a 302 response back to originating gateway with contact information of IMG 2 and IMG 0. Finally IMG 2 accepts the INVITE and the call is processed. The Redirect feature allows multiple IMG's to be configured as one large gateway.

 

There are two ways two enable the Redirect feature the first is by enabling a field in the Route Table. The other way of enabling the Redirect feature is to create a route list. Within that Route List will be multiple channel groups. Within these Channel Group entries will be a field named 'Channel Group Type' which will enable the redirect feature for that channel group within the route list.

 

Note: There must be multiple channel group entries under the Route List with Redirect enabled for the feature to function properly.

 

Below shows the two ways to enable the Redirect feature. See Related Items Heading below for more information and examples on how to configure the Redirect feature.

 

Configuration:

The Redirect Feature is configured in either the Route Table or Route List. See Below

 

Route Table:

  1. Right Click on IMG EMS object tree and select New Routing Configuration. This will create a Routing Configuration object.

  2. Right Click on Routing Configuration object in object tree and select New Route Tables this will create a Route Tables object.

  3. Right Click on Route Tables object in the object tree and select New Route Table. A Route Table Pane like below will appear. Within this Route Table Pane is a field which states 'Would you like to Redirect call'. To enable the Redirect feature, select Yes

    SC_SIP_RouteTable_RedirectCall.png
     

  4. Once the Route Table is configured it will be accessible to the Channel Groups Route Table field.

 

Route List:

  1. Right Click on IMG EMS object tree and select New Routing Configuration. This will create a Routing Configuration object.

  2. Right Click on Routing Configuration object in object tree and select New Route Lists this will create a Route Lists object.

  3. Right Click on Route Lists object in object tree and select New Route List. A Route List Pane like below will appear. Fill in the applicable fields.

  4. Right Click on the Route List object and select New Channel Group. A Pane like below will appear. Within this pane will be a selection for 'Channel Group Type'. The drop down menu will allow you to select Redirect. See Below.

    SC_SIP_Redirect_RouteListPane.png
     

  5. At this point whichever Channel group selected will have the SIP Redirect Enabled on it.

 

 

Additional Information:

Refer to Diagram above:

 

Related Topics:

SIP Redirect IMG Initiated 302 - Example