Planning channel groups

When you know how your applications are going to use the telephony environment, you can plan how to assign the trunk channels to channel groups. This is necessary if you cannot obtain the called number from the switch, but you want calls for different voice response services to be handled by different applications. Assigning channels to channel groups might also be necessary if other differences in signaling characteristics are required.

How many channel groups do you need?

  1. Determine how many channel groups will satisfy the requirements of your applications.
    1. Determine which line signaling protocols (for CAS, E&M Wink Start, FXS Loop Start, and so on) are required to establish switch connectivity for each channel group. Think about the switch facilities and other characteristics that are required by the applications you plan to make available (see your “Planning Checklist” in the Blueworx Voice Response for AIX: General Information and Planning information). Compare these with the Signaling type templates. Make a note of the templates that best match your requirements and choose the most suitable for each application.
      Note: Some ISDN protocols do not support call transfer. If it not available with your protocol, think about using CAS protocols on some channels, for applications that need to offer call transfer.
    2. CAS only: Determine whether channels are to allow incoming or outgoing calls, or both. This is known as direction. If you want to restrict some channels to either incoming or outgoing, you will need at least two channel groups. Although your applications might receive incoming calls only when in production, you might need to make outgoing calls while the applications are under development.

      To specify direction on CCS protocols you must configure the switch lines on the switch side.

    3. You can use a channel group to specify the same area code for several channels.
    4. For each direction, area code, and protocol, you need one channel group.
  2. Decide how many channels to dedicate to each application.
  3. Allocate the channels on each trunk to channel groups. 30 channels are available on an E1 trunk, and 24 channels are available on a T1 trunk. The total number of channels is limited by your Blueworx Voice Response license. To maximize availability, you might want to divide the channels between trunks for a specific application.
  4. Assign channel identification (phone numbers) to each channel.

Figure 1 shows an example of steps 1 to 3, with 24 T1 channels on two trunks. Figure 2 shows an example of how applications are allocated to channels in one of the channel groups.

Figure 1. Example of assigning channels to channel groups
This example shows nine applications divided into four groups. Group 1 consists of applications 1 and 2 and needs a total of 12 channels to run these applications. Group 2 consists of applications 3, 4, 5 and 6 and needs a total of 30 channels. Group 3 consists of just application 7 and needs 3 channels. Group four consists of applications 8 and 9 and needs 3 channels. All nine applications need a total of 48 channels, this means that two T1 trunks of 24 channels each are required. Trunk 1 has channels 1 to 6 allocated to group 1 and channels 7 to 24 allocated to group 2. Trunk 2 has channels 1 to 6 allocated to group 1, channels 7 to 18 allocated to group 2, channels 19 to 21 allocated to group 3 and channels 22 to 24 allocated to group 4.
Figure 2. Example of allocating applications to channels
This example shows the channels in group 1 (from the example in figure 5) with telephone numbers assigned. Both applications in group 1 have the same area code (123). The telephone number 8881234 is assigned to half the channels in the group and the application profile 1238881234 is associated with application 1. The telephone number 8885555 is assigned to the other channels in the group and the application profile 1238885555 is associated with application 2.