Introduction

Migration from legacy private branch exchanges (PBXs) and voice messaging systems to IP telephony systems is a challenge for many organizations. It would be unrealistic to expect any organization looking to deploy IP-based voice systems to immediately replace all of its installed legacy voice systems when the decision is made to implement an AVVID solution. Therefore, we can expect that we will face the challenge of integrating legacy systems with the respective AVVID components.

In addition to making the proper physical connections, system applications and user features must also be preserved. This preservation can be achieved with different levels of compatibility, depending on the method of integration that is available. Selecting the best migration strategy involves understanding the capabilities of the existing equipment and the AVVID components, as well as understanding what features and applications are most important to users. Some features may be unavailable during migration, while others may not be possible even after the migration is complete. Most organizations consider their phone system as a whole to be mission-critical, and they will not tolerate any loss of functionality during a system migration. Therefore, it is important for system designers to be aware of any caveats up front and set user expectations accordingly. In this chapter, we will investigate the possible options and evaluate the trade-offs...