The first chapter should have given you an understanding of the evolution of data and voice networks and the various components of IP telephony (IPT) networks. IPT merges separate voice and data networks into a single, converged network. This change requires fine-tuning the existing network infrastructure.
To facilitate a successful IPT rollout in an organization, you should follow the planning, design, implementation, operation, and optimization (PDIOO) methodology. This widely accepted procedure, outlined in this chapter, ensures the smoothest, most efficient path to a successful IPT deployment. In fact, the best practice is to follow the PDIOO methodology while deploying any new technology. Technologies that are deployed without following the PDIOO methodology usually end up in broken, unscalable, and unoptimized networks. To avoid the time delays that increase the total cost of the project, make a decision from day one to follow the PDIOO methodology while deploying IPT.
As a network design engineer who is engaged in the PDIOO of IPT networks, you should have a solid understanding of packetized voice technology, voice products, TDM network inter-actions, and IPT technology and components.
This chapter discusses each stage in the PDIOO methodology and explains how this approach can help you to achieve your goals and smoothly migrate the legacy telephony network to an IPT network. Figure 2-1 shows the complete PDIOO methodology to deploy the IPT network and various subtasks within each phase.
As shown in Figure 2-1, the whole project typically starts with the customer issuing a Request for Proposal (RFP). IPT vendors respond with the IPT network proposal based on the requirements given in the RFP. The planning phase starts immediately after the customer decides on a particular vendor solution. Chapter 3, “Large-Scale Enterprise Requirements for IP Telephony,” presents the sample RFP (this task is shown in dotted lines in Figure 2-1) for a fictitious customer, XYZ, Inc. The subsequent chapters in this book cover the various tasks shown in Figure 2-1 within the PDIOO phases to roll out IPT at XYZ, Inc. Figure 2-1 shows the PDIOO tasks for deploying the IPT solution in the dotted lines. Note that Figure 2-1 shows the ommonly followed tasks to deploy IPT by following the PDIOO methodology. However, depending on the type of the business and requirements, you might have to add extra tasks within each phase.
Planning is the first phase in the PDIOO lifecycle. A thorough execution of the planning phase tasks lays a solid foundation for the design of an IPT network.
One of the first important tasks in the planning phase is to understand the end customer’s expectations and requirements. These fall into two main categories:
Business expectations and requirements
Technical expectations and requirements
Note
The customer usually provides the business and technical expectations and requirements in the RFP document. You should use the information presented in the RFP first and then consult the voice network architecture group, IT groups, or other groups in the customer’s organization to obtain additional information.
From the business expectations and requirements point of view, you should understand the company’s goals and vision and analyze how these relate to the future IPT network. More particularly, information that might help you to execute the project in a timely manner and complete it within the projected budget includes the company’s goals for expansion in the next 4 to 6 years, its capital expenditures (CAPEX), its operational expenditures (OPEX), its return on investment (ROI), and its expectations regarding how long the project should take to plan, design, and implement.
From the technical expectations and requirements point of view, you should understand the company’s current and future needs regarding IPT network features and functionality. These expectations and requirements include general features that are required in the IPT network, such as network redundancy, high availability, convergence, security, network management, application requirements, utilization, performance, scaling requirements, and so forth.
After you understand these high-level business and technical expectations and requirements, the next phase is to conduct a site survey. One of the most important tasks in the site survey is to meet the right groups of people (i.e., LAN group, WAN group, IP network group, legacy PBX and voice-mail network group, applications group, etc.). Establishing the right contacts helps you to quickly obtain accurate information pertaining to the network.
While conducting the site survey, you need to obtain details regarding the following:
Existing LAN infrastructure, such as the LAN topology, equipment deployed, and current LAN QoS policies
WAN infrastructure, such as the WAN architecture, WAN equipment deployed, existing QoS policies, traffic flows, bandwidth assignments, and link utilizations
Layer 3 and Layer 2 infrastructure
IP addressing scheme, including how network services such as Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS) are deployed
Directory and messaging architecture
Layer 3 routing and routed protocols used in the network
Legacy telephony and voice-mail infrastructure and telephony features such as paging, operator, night bell, call center, Music on Hold, etc. deployed in the network
Legacy dial plan configurations
Current utilization and performance for voice and data networks
Current day 2 support and operations support process
After you collect the information by conducting the site surveys, you should perform a detailed network infrastructure assessment to ensure that the network will support IPT, that new systems and applications will be compatible with existing systems and devices, and that the new IPT system will perform as planned. The infrastructure assessment should include details regarding gaps in the infrastructure that need to be filled to support IPT and recommendations to strengthen the infrastructure to support the converged network.
Proper execution of the planning phase will lead to the following:
Realistic expectations of the scalability, performance, and features of the new IPT system
A network infrastructure that is able to support the IPT traffic
Identification of proper resources to accelerate the rollout of the IPT deployment
An IPT network that is aligned with business needs
Successful integration with legacy PBX and voice-mail systems or complete migration to an IPT network
Deployment of IPT applications and their integration with existing applications
Chapter 4, “Planning Phase,” covers the planning phase and various tasks involved. Appendixes B, “IPT Planning Phase: Network Infrastructure Analysis Questionnaire,” and C, “IPT Planning Phase: Telecom Infrastructure Analysis Questionnaire,” include Network Infrastructure and Telecom Infrastructure Analysis Questionnaires, respectively, that you can use to collect the information required in the planning phase and to perform the network infrastructure assessment and gap analysis.
After you complete the planning phase, you should begin working on the design phase of the IPT network. The goal of the design phase is to propose an IPT network design by using the information that is collected in the planning phase and the information that is provided by the customer in the RFP. You also need to collect additional information that is specific to IPT feature requirements. (Refer to Appendixes D, “IPT Design Phase: IP Phone Selection Questionnaire,” and E, “IPT Design Phase: IPT Requirement Analysis Questionnaire,” for the IPT Design Phase Questionnaires).
You should consider several different design alternatives before arriving at the final design. This proposed design should cater to the company’s current and future IPT needs.
The design phase consists of the following high-level tasks, through which different critical areas of the network are designed based on IPT network needs:
Network infrastructure design
Design of call-processing infrastructure and applications
Software version evaluation
Design validation
As shown in Figure 2-1, the goal of the design phase is to complete the preceding four design phase tasks and provide the design document that proposes an IPT network design that satisfies the customer’s needs. The design document should include the proposed IPT network architecture diagrams, recommended configurations for voice gateways, QoS recommendations for LAN/WAN, etc. Chapters 5, 6, and 7 cover the preceding four tasks involved in the design phase and explain the individual tasks with the help of the case study.
IPT network designers should review this design document with the voice network architecture team and infrastructure groups in the customer’s organization to ensure that the proposed design meets their requirements.
The first task of the design phase is to enable the existing network infrastructure to support IPT. Chapter 5 discusses the network infrastructure design tasks and focuses on the following design areas:
Choosing the IPT deployment model
Designing an IP addressing scheme, voice VLANs for IPT network devices, and IP routing
Evaluating and selecting Cisco IP phone models
Designing DHCP and TFTP services for Cisco IP phones and other IPT endpoints in addition to the use of DNS services
Designing quality of service (QoS) in the LAN
Choosing the in-line power standard and determining the additional hardware needs on the switches and the power requirements
Designing the LAN and WAN infrastructure for resiliency
Sizing the WAN links and design of QoS in the WAN
The second task of the design phase is to choose and size the IPT components, review and make recommendations to integrate or migrate current telephony applications with or to new IPT applications based on customer’s telephony requirements. Chapters 6 and 7 discuss the following design tasks:
Sizing the CallManager clusters
Sizing the voice gateways and gatekeeper
Preparing the IPT system to integrate or access the corporate Lightweight Directory Access Protocol (LDAP) directory
Choosing the right design steps to migrate or integrate with the legacy systems (PBX, key, voice mail, or unified messaging system)
Incorporating the fax and modem requirements in the IPT network
Deploying the conferencing and transcoding resources and sizing them based on the requirements
Recommending the security and network management solutions
Customizing and sizing the IPT applications such as Auto Attendant (AA) and call center application IP-ICD (Integrated Contact Distribution)
Designing and customizing the voice mail system
As with any other products, the Cisco IPT products have undergone many software revisions. New versions include bug fixes to the old versions and many new features. The heart of the Cisco IPT solution is Cisco CallManager. It interfaces with other applications as described in the preceding section to provide additional features and capabilities. You should refer to the Cisco CallManager Compatibility Matrix available on Cisco.com to ensure that all the software versions on the other IPT endpoints—such as IP Phones, voice gateways, and applications—are compatible with the CallManager version chosen for the deployment. The Cisco CallManager Compatibility Matrix is available at http://www.cisco.com/univercd/cc/td/doc/product/voice/c_callmg/ccmcomp.htm.
The final task of the design phase is to validate the proposed design by building a proof of concept (POC) lab and conducting the acceptance testing. The POC lab topology that you design should emulate the proposed network and must contain all the different IPT components that are proposed in the actual design.
This acceptance testing is necessary for a smooth rollout of IPT throughout the entire network. To ensure this, you, along with the customer technical team, should develop a test plan that clearly defines various unique test scenarios and then execute the test plan. Typical scenarios include testing the following:
Internal and external phone calls
Conference calls
IPT features that are deployed
Failover scenarios
Calls between the sites across the WAN
WAN circuit failure conditions
Recovery times for failures within the LAN
Access to voice mail and message notification
Voice-mail/PBX integration
Call routing and calling privileges
System restoration from the backup data
While you are going through this exercise, the time that you devote must be reasonable enough to cover all the test scenarios described in the test plan. Following are some clear advantages of going through this exercise:
Fix problems such as functionality issues, configuration errors, and design flaws that are discovered during the testing.
Make necessary changes in the design depending on the types of problems discovered.
Modify or adjust the procedures used to build the servers, deploy phones, migrate users, etc. based on the results. This ensures that the final deployment process is smooth and helps to make the IPT rollout faster.
Fine-tune and adjust the server configuration parameters during the testing phase to achieve minimal telephony service disruptions by conducting failover tests.
Ensure that all the critical elements are in proper working order.
Ensure smooth transition/migration to the proposed IPT design.
After you have documented the design phase on paper, the next vital phase in the PDIOO lifecycle is implementation. This phase helps to ensure that the deployed network delivers all of its desired functionality. This phase involves developing the implementation strategy and procedures.
In large networks, the company might subcontract some of the implementation tasks, such as physical deployment of IP phones, configuring the IP phones in the CallManager, and so forth. Hence, defining the process is important so that subcontractors can leverage this process and follow the methodology developed. This ensures timely resolution of any problems that are encountered during the implementation.
A good strategy for implementing the IPT rollout in large networks is to divide the whole project into small phases. Choose a small section of the network in the initial phase of the deployment. After you successfully complete the IPT deployment for the first phase, move to the other parts of the network in an orderly fashion.
You should monitor the network utilization statistics and the functionality of the newly deployed network at every stage. Keep a log of the problems reported by the users and modify the implementation procedures to ensure that users of the future IPT rollout do not face the same issues. At any given stage, resolve any unexpected behaviors and conduct thorough research on the root cause of the problems before further deployment.
An implementation strategy should have at minimum the following steps clearly defined and documented:
Identify the implementation team responsible for provisioning the new IPT system into the production network.
Identify and standardize the implementation tools that are useful in deploying IP phones and other IPT endpoints.
Document clearly the installation and configuration steps for various devices.
Define the migration user groups and timelines for the migration.
Inform users about the new phone system and plan for end-user training on using the new phone features.
Communicate routinely with telephone companies (telcos) to coordinate the configuration changes required on the central office switches and the support required for cutover to the new IPT system.
Provide updates to the PBX/voice-mail system and other telecom engineers and ensure that they perform the changes required on these systems for successful migration/integration of them to/with the new IPT system.
Prepare a telephone number management system to track the phone number allotments and changes.
Ensure that constant communication occurs between the implementation team and the design staff to exchange the problems faced in the field and solutions to the problems.
Define the escalation procedures to address the feature and functionality faults or network tuning requirements as discovered during implementation.
Provide the organization with a technical review for IPT-related field alerts that might affect the customer’s current implementation.
Communicate to the executive team and to the users if there is any downtime that could be caused by this deployment.
Depending on the customer’s organization and type of business, you might need to define additional strategic steps to successfully deploy the IPT network. Chapter 9, “Operations and Optimization,” covers the detailed implementation steps for deploying various IPT components and applications and introduces you to some of the implementation tools.
The last phase of the PDIOO life cycle is operation and optimization.
As opposed to traditional telephony networks, IPT networks have less need for expensive services and provisioning tools for moves, adds, and changes. Nevertheless, a solid support plan is essential to attain operational excellence for high availability and seamless quality.
Operation planning protects the networking investment and provides the operations staff the capability to proactively monitor the network to reduce problems. The following are the important steps that organizations should plan to execute for successful operation of the IPT network:
Provide training and hands-on expertise to the support staff on the IPT products operational tools, and network management tools.
Involve the key operational staff in the planning and implementation stage of the IPT project.
Define escalation procedures and provide resources such as the tools required and product, vendor contacts to troubleshoot user-reported problems and product issues.
Define a process to perform the software and hardware upgrades. The process should outline when to perform the software/hardware upgrades, who should be notified when performing the upgrades, etc.
Define procedures for managing configuration change requests.
Define the backup and restore procedures and backup schedules.
Establish a service and support contract with the IPT product vendor.
The optimization phase involves executing steps that help the network to deliver the best possible performance, thus decreasing network issues and reducing revenue losses caused by outages.
To optimize the network, the support staff should have a solid understanding of the available operation, monitoring, and optimization tools. Chapter 9 provides detailed information on various tools that are available in Cisco IPT products and optimization techniques.
These tools and procedures simplify network expansion, ensure the quality of the network and its applications, focus staffing and training needs, facilitate problem solving, and lower the total cost of ownership.
Following the PDIOO methodology ensures that the converged network solution is successful and cost effective throughout its life cycle.
This chapter briefly introduced you to the PDIOO methodology and tasks performed at every phase. After reading this chapter, you should have a solid understanding of IPT technology and the tasks involved in the PDIOO of an IPT network. Chapter 3, “Large-Scale Enterprise Requirements for IP Telephony,” examines the network of an organization that is planning to migrate to an IPT network and describes how to collect its IPT requirements as part of the PDIOO lifecycle.