The Elite Gateway* enables the transmission of voice and fax traffic over any IP network by digitizing voice and fax signals, encapsulating the information within IP packets, and then sending the packets across the IP network

How the Elite Gateway Operates

1. The TIM (Telephony Interface Modules) inside the Elite Gateway digitizes analog voice signals at 8 Kbps.
2. Elite Gateway system software handles the:
   • Capture of telephone number presented as DTMF tones.
   • Mapping the telephone number to the IP address of remote Elite Gateway.
   • Setting up calls with remote Elite Gateways utilizing H.323 call control protocol.
   • Digitizing, compressing and encapsulating the voice into IP packets and transmission of the IP packets onto the Ethernet LAN.
3. A router attached to the LAN forwards the IP packets across the WAN, where they will be received by another Elite Gateway at the remote.
4. The process is reversed at the remote Elite Gateway.

ATPM
To allow you to easily dial a telephone or fax on the network, the Elite Gateway maps a series of dialed digits to the IP address of the remote Elite Gateway whose phone or fax you are calling. This mapping information is contained in a database inside each Elite Gateway called the dial plan.

Based on the dial plan, the Address Translation and Parsing Manager (ATPM) inside the Elite Gateway translate telephony numbers to IP addresses of remote Elite Gateways. The ATPM collects telephone number dialed by users, decides whether the dial string is part of the dial plan and, if it is, maps it a remote Elite Gateway. When the call is set up to the destination, a substring of the original dial string will be sent along to the remote Elite Gateway.

Destination
The destination is where a call is terminated. Typically, for inbound calls from IP network, the Elite Gateway terminals the call at one of the telephony ports. The destination for the call is the telephony port where the call terminated. For calls initiated from telephony ports, the Elite Gateway forwards the call to a remote Elite Gateway via IP network, and the remote Elite Gateway terminal the call. The destination of the call is the remote Elite Gateway.

Hunt Group
Instead of directly mapping a phone number to a destination, the ATPM first maps the phone number to a group of destinations known as a Hunt Group. A hunt group is a group of destinations that are equivalent. For example, the customer support group of a company might have 20 people who can handle support calls. Access to customer support is through a single phone number but the next available support person is actually connected upon each incoming call. These 20 phones would be configured as a hunt group. A hunt group consists of a phone number and a list of destinations (members of the group). When an incoming phone number matches the phone number of the hunt group, the Elite Gateway attempts to terminate the call at each of the destinations in the hunt group, one at a time until a call is successfully completed.

Every destination that can be reached by dialing a phone number is a member of at least one hunt group. When an address is presented to ATPM for lookup, the output is a hunt group ID number. As a second step, the hunt group ID is presented to ATPM to get the list of members. To effectively bypass the hunt group feature, simply make a unique hunt group for each destination and one member in each hunt group.

Dial Plan
The dial plan is a database inside the Elite Gateway for the ATPM to map telephony numbers users dialed to the IP address of remote Elite Gateways. The dial plan consists of the destination table, hunt group table and the address table. Users need to setup these tables, so that the Elite Gateway knows how to setup calls with remote Elite Gateways.

Address Table
The address table maps a phone number to a hunt group. The table contains entries that specify the following information:
• Telephone number
• The hunt group the phone number maps to.
• The minimum number of digits to collect before the ATPM starting address lookup.
• The maximum number of digits the ATPM collects before it considers the dial string is complete.
• Number of digits forward to the destination.

Address table sample:

Address Entry Hunt Grp_Id Min. Digits Max. Digits Prefix strip Prefix Address 200 1 3 3 0 None 201 3 3 3 0 None 899 11 3 3 0 None 8 11 3 3 0 None 0 5 1 1 0 None 03 5 10 10 2 "0"

Hunt Group Table
The hunt group table maps a hunt group to a list of destinations.

Hunt group sample:

Group id Type #Members Member ids 1 2 1 1 3 2 1 2 5 2 1 4 11 2 1 11

Destination Table
The destination table maps a destination to a telephony port or the IP address of a remote Elite Gateway.

Destination table sample:

Dest id Mode Destination 1 Local PORT = 0 3 Local PORT = 2 5 Local PORT = 4 11 H.323 Dest = 192.168.0.55/1720 TCP 12 DNS Dest = accel0021.dyndns.org /1720 TCP

The Elite Gateway handles DTMF relay per H.323 specifications. Certain third party VoIP devices may handle DTMF relay per IMTC standard. For the Elite Gateway to interoperate with those VoIP devices, users need to specify which remote VoIP devices uses IMTC conforming DTMF relay technique. Refer to CLI command Error! Reference source not found. on Chapter 8 for detailed information on how to select DTMF relay mode.

Voice Codecs
Voice codecs supported by the Elite Gateway include G.711, G.723.1 5.3kbps, G.723.1 6.3kbps and G.729 AB. When setting up a call, two Elite Gateway automatically negotiate with each other until an agreed upon codec is determined.

This applies to:

Elite Gateway*