Cisco AVVID and IP Telephony Design and Implementation

by Wayne Lawson

Overview

Corporate demand for AVVID solutions is rapidly increasing - engineers will need this book Cisco AVVID (Architecture for Voice, Video and Integrated Data), the latest development from Cisco Systems, is redefining the way businesses communicate. AVVID allows businesses to transmit voice, data, and video over a single integrated architecture called a "multiservice" or "converged" network.

Cisco AVVID Design and Implementation is designed to be a complete desk-reference for network administrators and engineers responsible for a complicated AVVID network. Covering history, protocols, hardware, servers, switches, bridges, routers, and discussions about implementation issues, realities of cost, requirements and network limitations. Engineers will learn how to design and build a comprehensive Cisco AVVID network infrastructure.

Product Details

ISBN-13:	9781928994831
Publisher:	Elsevier Science
Publication date:	01/04/2002
Pages:	560
Product dimensions:	6.00(w) x 9.00(h) x (d)

About the Author

Wayne A. Lawson II (CCIE # 5244) currently with iPexpert, Inc., formerly a Systems Engineer with Cisco Systems in Southfield, Michigan. With over 9 years of experience in the IT industry, his certifications include the Cisco CCIE, CCNA, & CCDA, Nortel Networks NNCSE, Certified Network Expert (CNX) Ethernet, Microsoft MCSE, Novell CNE, and Banyan Systems CBE. His core area of expertise is in the Routed Wide Area Network (WAN) arena as well as the Campus Switching arena.

Read an Excerpt

Introduction to IP Telephony
IP telephony is a term used to describe a suite of products and solutions used to transport voice traffic over a data network. Utilizing Internet Protocol (IP) as a transport mechanism, IP telephony allows you to create a converged network in which all communications (voice, video, or data) share the same infrastructure. There are numerous benefits to this type of infrastructure, including simplified administration, cost savings on telecommunications fees, and unified messaging services.

Simplifying Administration

Almost every mid- to large-sized corporation has a large data infrastructure and along with it, they probably have a large infrastructure built for voice-based traffic. These networks, while both crucial to the organization, share no common thread. Although they may share the same cabling, and even in some cases the same protocols (such as IP), they are still very different types of infrastructures. Two different groups within the corporation administer them, they utilize the equipment of different vendors, both require separate leased lines or plain old telephone service (POTS) lines, and funding for both probably come from different budgets. With the IP telephony solution, these two infrastructures are collapsed into one IP-based network, allowing all communications to share the same administration, ultimately saving time and money for the corporation.

As we discussed earlier, an organization typically has two groups, a voice group and a network group. Under the old world telephony solutions, these two groups perform very different functions, and in a figurative sense, almost speak different languages. With the IP telephony solution,these groups are collapsed into a single resource pool. Voice and data, while still very different types of traffic, are administered by the same group. Customer service and satisfaction will also benefit from this type of infrastructure. Instead of an end-user having to call the network group for one problem and the voice group for another, the user has a single point of contact for their communication needs.

Utilizing Toll Bypass

One of IP telephony’s key features is also one of its most enticing benefits, a feature known as toll bypass. Toll bypass allows an organization to utilize its existing data infrastructure to make calls within the organization. Imagine a multinational organization with branch offices spread throughout the world. In the old-world solution, any time one office placed a call to another, the telephone systems of each office would employ the services of telecommunications service providers to place a call within their own organization. If you have ever traveled, you may have experienced the sting of how expensive international calls can be. I placed a call on a business trip from a branch office in Moscow to their headquarters in Cleveland; the call lasted around 40 minutes, and the bill turned out to be $300.00. So you can imagine how expensive international telecommunications must be for the day-to-day operations of a multinational organization. Now imagine that same scenario using IP telephony, placing that same call from the branch office in Moscow to headquarters in Cleveland, this time utilizing the IP telephony solution. Instead of utilizing the telephone company’s services and infrastructure, you would employ the existing leased data lines between the two sites. Now the only price you are incurring is the fixed price you pay each month for the leased line that was already there. As I am sure you can see, IP telephony has the potential to save an organization a great deal of money.

Linking Communications with Unified Messaging

Unified messaging is both one of the goals and benefits of a truly converged network. It links an end-user’s voice-mail, e-mail, and fax solutions so they are essentially one entity. With IP telephony, a user could listen to his e-mail, review his voice-mail via software on his PC, review e-mail or listen to voice messages on an IP telephone. Cisco, as well as other vendors, have, and are, developing software applications to utilize unified messaging. We will discuss some of these solutions in the sections to come. Choosing to Implement IP Telephony

IP telephony sounds great, right? Shouldn’t every organization have implemented it by now? Well, first of all, you should keep in mind that voice traffic and regular IP data traffic are two completely different solutions. Regular Transmission Control Protocol/IP (TCP/IP) data traffic is very resilient. It can be forgiving of slow wide area network (WAN) links, lost packets, and the reception of packets out of sequence. In fact, TCP/IP operates in just that way, taking data and segmenting it into several packets and transmitting the data via the best possible path. It is not concerned with the order in which the data is received, or the path it takes to get there, because the end device is responsible for the reassembly and resegmentation of the data. Voice traffic, on the other hand, is not so forgiving, nor as resilient. Even though the voice traffic is being converted to IP packets, it is still voice traffic. IP telephony depends on packets being received in the same order in which they were sent; if a packet is lost, then it should remain lost, as retransmitting the packet would only confuse the person on the receiving end of the call. In order to accomplish this, you must incorporate several new features on your routers and switches, such as Queuing and Real-Time Transport Protocol (RTP). In fact, in order to make IP telephony a reality, your infrastructure is going to need quite a few enhancements. There are several components that must be added to your infrastructure. These components include, but are not limited to, specialized router interfaces, specialized local area network (LAN) switch modules and interfaces, IP telephone handsets, Cisco CallManager servers, and Cisco Unity Mail, as well as other unified messaging solutions. In addition to the required hardware, there are several applications that will also help you to realize the benefits of IP telephony. Applications such as Cisco’s WebAttendant, AutoAttendant, and Personal Assistant, as well as third-party software should also be incorporated into your IP telephony solution.

IP Telephony Components

The components that must be added to your infrastructure in order to facilitate IP telephony are what really blur the line between the traditional voice infrastructure and your data infrastructure. Here we cross a line into a new realm of devices—but are they voice or are they network? The answer, of course, is that they are both. I think an important point to remember when considering a converged infrastructure is that no matter what we are dealing with, voice, video, or data, it is all communications. This is the information needed for the end-user to effectively carry out his or her business. Perhaps we should begin to consider ourselves communications engineers as opposed to using the traditional network engineer or voice systems administrator titles that have helped to separate the different disciplines for decades. In this section, we will discuss some of these components and their features.

Table of Contents

Chapter 1: Old World Technologies

Chapter 2: New World Technologies

Chapter 3: AVVID Gateway Selection

Chapter 4: AVVID Clustering

Chapter 5: Voice and Video Gatekeeper Design

Chapter 6: DSP Provisioning

Chapter 7: AVVID Applications

Chapter 8: LAN/WAN QoS in AVVID Networks

Chapter 9: AVVID Dial Plans

Chapter 10: Single Site Solutions

Chapter 11: Multi-Site Solutions

Chapter 12: Solutions Fast Track

Appendix A: AVVID Protocols

Appendix B: IP Phone Services