Optimize and design more effective voice / IP telephony networks with this definitive guide. Benefit from author's vast experience in designing and building large VoIP networks. Learn how to avoid deployment pitfalls through real-world examples and case studies, and understand various VoIP feature sets and their benefits to optimize a service provider network. Improve large-scale VoIP network design to better meet customers' voice application needs. 63% of 500 large enterprise-scale corporations responded to a May 2005 indsutry survey conducted by Network World that they have already implemented Voice over IP (VoIP), or are planning to implement within 2 years. The primary driver for the rise in VoIP adoption are the cost-savings and business productivity gains VoIP provides. "Deploying and Operating a Voice over IP Network" offers real-world examples and case studies related to planning and designing a large-scale VoIP network for either enterprise network or service provider considerations. To design a high-quality VoIP network, network designers must have a thorough understanding of numerous IP and VoIP protocols and the complex features and roadmaps associated with Cisco products and solutions. This title details the functions of these protocols and features and outlines the benefits they can provide when deployed in the live network. The authors provide a comprehensive overview of existing VoIP protocols and solutions, such as H.323, SIP, and MGCP, and progresses to discussions on designing, optimizing, and troubleshooting a large-scale H.323 VoIP network in a service provider environment. Readers gain details on the various components of H.323 VoIP network design and management and benefit from extensive examples of VoIP network design and optimization according to Cisco best practices. Evan Zeng, CCIE No. 4933, joined Cisco in 1998 as a senior project engineer for the Professional Services Team and is currently a design consultant for the Advanced Services Team in China. In this position, Evan's focus is on the design and deployment of new converged data/voice networks that provide telecommunication services using SS7, ISDN, R2, H.323, MGCP, and SIP protocols. During his tenure, Evan designed and installed the world's largest VoIP network for China Unicom.