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This guide provides general guidance for configuring VX for call routing, including concepts, where to start and the basics of configuring call routing with VX.

Call routing with VX requires several preparation steps:

Identifying Call Equipment Connections

To get started with configuring VX for call routing, make a list of the call equipment that is connected to your VX unit, including external telecommunications carrier lines (D1/T1, E1, PSTN) internal telecom equipment (PBX, desk phones) and computer networking equipment (Ethernet, VoIP servers). Use the attached VX Equipment Connections Worksheet to catalog your equipment connections. If there is more than one VX system in your environment, make note of the additional VX units as well on the worksheet.

VX Equipment Connections Worksheet

The VX Equipment Connections Worksheet helps you catalog the equipment that makes up your call network. In the top row of boxes, make a note of the equipment attached to your VX system that are a source of calls (inbound calls). In the bottom row of boxes, make a note of the equipment attached to your VX system that are a destination for calls (outbound calls). In most cases, the attached equipment should be listed in both rows since most call routing equipment can both send and receive calls. Make sure to include fax call systems and make note of other VX systems if you have more than one unit. If you are configuring more than one VX system as part of your call network, fill out a worksheet for each VX unit. Follow the descriptions below to fill out the fields in each box:

  • Name - An identifying name for this device, such as "AT&T ISDN" or "MS OCS".
  • TDM- Check this box to indicate that the equipment is connected via Time-Division Multiplexing, this includes digital voice and data lines from commercial telecommunications carriers and public switched telephone network (PSTN) lines. In addition, check one of the protocol options listed below TDM:
    • CAS - Channel associated signaling protocol
    • SS7 - Signaling system 7 protocol
    • ISDN - Integrated services digital network protocol
    • Analog - Plain old telephone service line (not digital or data service)
  • IP- Check this box to indicate the equipment is connected via Internet Protocol (usually through an Ethernet connection). In addition, check one of the protocol options listed below IP:
    • SIP - Session Initiation Protocol specified by the Internet Engineering Task Force
    • H.323 - ITU Telecommunications Standardization Sector recommended protocol for audio-visual communications over packet networks
    • BSP - NET proprietary communications protocol. This protocol is only used for communication between VX nodes.
  • Serial - Check this box to indication that the equipment is connected via serial connection. This type of connection requires a VX add-in card.
  • BRI - Check this box to indication that the equipment is connected via Basic Rate Interface connection. This type of connection requires a VX add-in card.
  • VX Slot - The VX slot where this line or device is connected. For equipment connected via IP, enter 15 for the VX virual slot. Leave this space blank for Serial and BRI connections.
  • VX Port - The VX port where this line or device is connected. For equipment connected via IP, leave this empty for now. Also, leave this space blank for Serial and BRI connections.
  • Trunk Group - Leave this blank for now. The Trunk Group name is determined in the next procedure.

Proceed to the next section after completing this worksheet.

Mapping Call Equipment to Trunk Groups

In the VX system, Trunk Groups are used as the logical representation of a physical equipment connection (such as an ISDN line) or a virtual connection (such as VoIP server connected via IP/SIP). Call routes in VX use Trunk Groups as sources and destinations for calls, and so Trunk Groups must be defined before defining a call route.

Within VXbuilder, call equipment connections are represented in a number of ways. TDM connections are represented in the VXbuilder configuration tree Chassis node as a Slot (expansion card) and Port (cable connection). IP connections are configured under the Networking node of the configuration tree (usually as an Ethernet Adapter), however for call routing purposes, IP connections are mapped to a virtual Slot (Slot 15) and then further defined as virtual Ports. (Serial and BRI connections are configured and represented differently in VXbuilder, and are beyond the scope of this article.)

Slots and Ports for TDM and IP Connections

In VXbuilder, TDM and IP connections must be configured as sets of Slots and Ports. Once the Ports are configured for these connections, they can be mapped to Trunk Groups so that these connections can then be represented in a Call Route.

Trunk Groups are set up as inbound (call sources) or outbound (call destinations), relative to the VX unit. This means that a call coming from an outside line through VX and into your local network is considered an inbound call. Calls coming from within your internal network through VX to outside lines are also considered inbound calls. This classification is important because VX call routing instructions assigned to the incoming Trunk Groups determine how a call will be routed, rather than outgoing Trunk Groups.

SIP Inbound Call Routes

Mapping SIP calls inbound to VX requires an additional configuration item beyond a virtual Slot and virtual Port: a SIP Inbound Call Route. This additional configuration item is required to map inbound SIP calls to a virtual Port into a Trunk Group. See the instructions below for creating a SIP Inbound Call Route.

To Create a Trunk Group

  1. In VXbuilder, select the Trunk Group node in the configuration tree (node-root > Telephony > Trunk Groups).
  2. Add a Trunk Group by selectnig Edit > Insert... and clicking OK.
  3. Double-click the new Trunk Group or select Edit > Edit... and adjust the settings as needed.

Trunk Groups must mapped to a Port or channel, otherwise no calls are routed to the Trunk Group.

To Map a Port to a Trunk Group

  1. In VXbuilder, add a Slot (Slot 15 for a virtual slot) in VXbuilder in the Chassis node in the settings tree (node-root > Chassis).
  2. Add a Port in the new Slot node (node-root > Chassis > Slot x: slot-name).
  3. In the configuration tree, select a Slot node (node-root > Chassis > Slot x: slot-name).
  4. Select a Port from the Slot x Ports list for that Slot.
  5. Edit the Port by double-clicking it or select Edit > Edit...
  6. In the Edit Slot x Port x dialog, in the TrunkGroup field, select the Trunk Group you created in the previous procedure.

To Map Inbound SIP Calls to a Trunk Group

  1. In the VXbuilder configuration tree, select the SIP Inbound Call Routing node (node-root > Telephony > SIP Inbound Call Routing).
  2. Add a SIP Inbound Call Route by selecting Edit > Insert... and clicking OK.
  3. Edit the Inbound Call Route by double-clicking it or select Edit > Edit...
  4. In the dialog, enter an Address/FQDN and Mask for the SIP-based call equipment.
  5. In the Trunk Group field, select your inbound SIP Trunk Group.

For the purposes of explanation, the following VX configuration is assumed for the call routing examples. In this minimal configuration, VX is connected to a TDM / ISDN via a card in a VX chassis slot #1 with 2 ports and a IP / SIP connection (via Ethernet) to a SIP-based PBX which is represented by virtual Slot 15 and virtual ports 1 and 2.

Ports Mapped to Trunk Groups 1-4

In this example, Trunk Groups are mapped directly to Ports for the sake of simplicity, but VX is not limited to this configuration. More than one Port can be mapped to the same Trunk Group and the bandwidth (Channels) of a single Port can even be divided among two or more Trunk Groups, if required by your call routing environment.

Creating Call Routes

In VX systems, call routing logic is captured in one or more Call Routes. Call Routes are contained in Call Route Tables which are assigned to Trunk Groups. Calls coming into a Trunk Group are processed using the Call Route rules contained in the attached Call Route Table, and passed to the appropriate outbound Trunk Group, as show in the illustration below.

Call Routes and Trunk Groups

Before creating a Call Route, you must first create a Call Route Table. The Call Route Table (along with its Call Routes) are then assigned to a Trunk Group.

To Create a Call Route Table

  1. In VXbuilder, connect to the VX node to get its current configuration.
  2. In the configuration tree, select the Call Routing node (node-root > Telephony > Call Routing)
  3. From the menu, select Edit > Insert...
  4. Review and update the insert parameters and click OK.

Call Routes Tables require at least one Call Route Entry in order to effectively route calls. VX call route routing logic is composed of three primary elements:

  1. Incoming Trunk Group - The source of the call which may be from external call network sources (PSTN, ISDN) or an internal call network (PBX).
  2. Number Matching Rule- A rule for identifying called numbers (call destination) so that the call may be routed a particular way, for example, a rule for all numbers starting with the area code 510.
  3. Outgoing Trunk Group- The destination of a call, which is typically another call routing system, such as a PBX, a public telephone network or other voice call processing system.

To Create a Call Route

  1. In VXbuilder, navigate to the Call Routing node of the configuration tree (node-root > Telephony > Call Routing).
  2. Select a Call Route table under the Call Routing node.
  3. Select Edit > Insert...
  4. Review and update the insert parameters and click OK.

Example ISDN to SIP Call Route

The following is an example of a very simple call route for the incoming ISDN Trunk Group illustrated in the previous section. This call route captures all incoming calls, regardless of the called number, and routes them to the SIP PBX via the SIP outbound TrunkGroup.

Simple ISDN inbound Call Route

The critical settings in this Call Route are as follows:

  • Match Rule - This setting matches all called numbers, regardless of their pattern, so this call route will apply to all inbound calls on this Trunk Group. For more information about creating and using Match Rules more selectively, see Phone Number Matching and Translation.
  • Translation Rule - This setting takes the called number and appends the IP address of the SIP PBX for proper routing. For more information about creating and using Match Rules more selectively, see Phone Number Matching and Translation.
  • Destination  (o) Other - This setting routes the call to an existing Trunk Group.
  • TrunkGroup - This setting specifies the Trunk Group where the call is routed.

The final step in applying this Call Route is to apply it to an inbound Trunk Group. In this example, the Call Route will be applied to the ISDN inbound Trunk Group.

Assigning Call Routes to Trunk Groups

Call Route Tables must be assigned to a inbound Trunk Group in order to be applied to calls coming into a VX system. After a Call Route Table is assigned to a Trunk Group, any calls that come into VX from that Trunk Group are processed according to the Call Routing rules in the assigned Call Route Table.

Call Routes for Outbound Trunk Groups

Call Route tables are attached to both inbound and outbound Trunk Groups. However, VX only processes call routing instructions for calls coming into the VX chassis, so call routing instructions are processed only for inbound Trunk Groups and ignored for outbound Trunk Groups.

To Assign a Call Route Table to a Trunk Group

  1. In VXbuilder, select a Trunk Group node in the configuration tree (node-root > Telephony > Trunk Groups).
  2. Double-click the Trunk Group where you want to set the Call Route Table.
  3. In the Inbound Call Only Settings, Route Table setting, select a Call Route Table.

Example Trunk Group with Call Route Table Assigned

The following example shows an inbound ISDN Trunk Group with the ISDN inbound Call Route Table assigned.

Example Trunk Group with Call Route Table Assigned

The important setting in this Trunk Group is the Inbound Call Only Settings, Route Table setting. This setting specifies the Call Route Table that is used to process inbound calls on this Trunk Group.

For more information on Call Routing, see the following topics:

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