Table of Contents:

Definition and Overview

1. Introduction

2. Softswitch Architectural Overview

3. Network Element Failure Scenarios in the Network Office

4. High-Availability Techniques for the Network Office

5. Software Failure Analysis

6. Conclusions

Self-Test

Glossary

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Softswitches communicate with and control a combination of media gateways or integrated access devices (IADs) (via media device control protocols, such as media gateway control protocol [MGCP]), session initiation protocol (SIP) phones, H.323 devices, and with application servers. (see Figure 2).

Figure 2. Softswitch Network Diagram

A typical network will include a number of softswitches, each comprised of several elements with specific requirements for communication between those elements. Softswitch elements are distributed across multiple networked computing platforms. Some of these elements include the following:

• Call control
• Signaling gateway
• Call routing
• Billing
• System management

In order to achieve a highly available solution, it is essential to consider hardware and software failures as well as situations arising from the networked operation of softswitch elements.