Introduction
Key Features
How This Application Works
Component List

Introduction

This application permits the TDM infrastructure used to network TDM PBXs to be replaced with an IP infrastructure. Doing so permits you to take advantage of the cost savings provided by toll bypass networks, and can offer important services such as policy-based routing, centralized dial plan provisioning, and tandem PBX replacement. All DPNSS and QSIG features are supported transparently.

The Cisco EGW 2200 allows TDM PBXs to be IP-enabled through use of a voice-enabled router, also referred to as a DPNSS or QSIG media gateway. For TDM PBX to PBX calling, signaling is backhauled to the Cisco EGW 2200 which performs the call setup. Unlike networking TDM PBXs with Cisco CallManager, this application does not require DPNSS or QSIG interworking. Instead, it uses transparent transmission of the signal from one PBX to another over the IP network. The Cisco EGW 2200 performs the call setup between the TDM PBXs on the IP network, and can also provide centralized dial plan and policy-based call routing that simplifies PBX dial plans.

The TDM PBXs can be DPNSS or QSIG, but not a mix.

Figure 1. Tandem Signaling and Toll Bypass Application

For more information on a component in the illustration, point to it. To go to a detailed description, click on it. Click a connector line for information on the interfaces and connections between components.

Key Features

• Toll Bypass using IP-based infrastructure
• DPNSS or QSIG feature transparency
• Centralized dial plan administration
• Policy-based call routing

How This Application Works

TDM PBXs are IP-enabled through use of a voice-enabled router, also referred to as a DPNSS or QSIG media gateway. The PBX is connected to an E1 interface on the media gateway, and the gateway interfaces with the IP network through one of its Ethernet ports.

The media gateway packetizes DPNSS or QSIG TDM call control signaling and backhauls it over the IP network to the Cisco EGW 2200. The Cisco EGW 2200 performs the call control required for call setup between the TDM PBXs on the IP infrastructure. The media gateway also packetizes all voice transmission on the network for calling between the PBXs.

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Components List

This application uses the following components. See the Component Chart for hardware and software specifications and see component details for links to overviews and detailed requirements and recommendations for each component.

• Cisco EGW 2200, in either a single or dual (active/standby) configuration
• At least one Cisco DPNSS or QSIG media gateway for each PBX

Component Details

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