Cisco.IP.Telephony.Planning.Design.Implementation.Operation.and.Optimization [Electronic resources] نسخه متنی

Customer Requirements

This section lists the XYZ IPT network requirements. As mentioned at the beginning of this chapter, customers usually provide this information in the RFP.

While reviewing the existing voice network infrastructure, system administrators at XYZ have identified the following limitations in the current system:

Because of the multivendor PBX systems that exist in the network and the use of nonstandard, propriety signaling mechanisms and interfaces on the PBX systems, XYZ cannot interconnect the PBX systems to save the communications costs on the interoffice calls.

Some PBX systems and key systems are old and lack the functionality and the call features required.

Nonavailability of empty slots on the PBX systems is preventing the expansion plans.

Because the equipment is old, cost of replacement parts is high.

Costs incurred in maintaining the PBX and voice-mail systems by external vendors have increased substantially over the years, resulting in more recurring expenditures.

Coordinating with external vendors to implement the changes or additions is causing an extra delay and impacting negatively on the company productivity figures.

Moves, adds, and changes cost $200 to $250 every time a staff member relocates to a new office. This cost is for the PBX engineer to reprogram the PBX systems and the cable contractor to install the new connection. This whole process sometimes takes up to two business days for completion, which impacts overall company productivity.

These system limitations and extra costs have forced the administrators of XYZ to consider the migration to IPT solutions. The following sections provide the minimum requirements for the proposed IPT network.

System Architecture

XYZ has been expanding its operations rapidly because of growing demand for its products. To protect the investments made and to achieve quicker expansion, XYZ requires a scalable call-processing system that

Requires minimal redesign in case of an expansion.

Provides redundancy and load balancing.

Optimizes bandwidth utilization on the WAN links for voice traffic.

Supports keeping the call control at the central sites and providing local call processing capability on the WAN routers at the branch sites during WAN link failure.

IP Phones

At XYZ, the IP phones can be categorized as follows:

Employee phones

Assistant/secretary phones

Conference/meeting room phones

Lobby/break room phones

The employee and assistant/secretary phones must support headsets. Assistant/secretary phones usually have multiple lines. The phones and headsets are required to work with hearing-impaired users. High-quality conference phones are required in meeting rooms for conference calls. Lobby/break room phones do not require; PC connectivity from the phones.

The phones must obtain power from the wiring closet switches and, if required, must work with other vendors' networking equipment by taking advantage of interoperable standards.

Integration and Replacement of Legacy PBX Systems

All the sites currently have either PBX systems or key systems. These systems are not interconnected. A phased migration to the new IPT system is required for the San Jose site because of the large user presence. The PBX system at the San Jose site requires integration with the new IPT system. At all other locations, the PBX lease periods are ending; hence, IPT systems can replace legacy PBX systems.

Integration and Replacement of Legacy Voice-Mail Systems

There are two Avaya Octel voice-mail systems, one each at San Jose and Sydney. The Octel system at San Jose has mailboxes for all the employees in the United States. Similarly, the mailboxes for all the users in Australia reside on the Octel system in Sydney.

As a part of the new technology deployment, XYZ would like to deploy a new voice-mail system that supports unified messaging. The proposed voice-mail system architecture should have high availability and redundancy. The proposed voice-mail system should be able to leverage the already deployed messaging infrastructure.

In the initial deployment, the international office (Sydney, Melbourne, and Brisbane) users' mailboxes are migrated from the Octel system to the new voice-mail system. The Octel voice-mail system at the San Jose Headquarters site will continue to exist.

The new proposed voice-mail system at Sydney must be integrated with the existing Octel voice-mail system at the San Jose central site. The networking of the Octel and new voice-mail systems is a requirement to route voice mails between the two systems.

Voice Gateways

Every location requires a voice gateway to connect to the local PSTN and must support T1/E1 PRI trunks. Each site routes local calls via a PSTN connection that is terminated on the local gateway.

The remote branch gateways should provide call-processing functionality to the connected devices in case of WAN link failure. The IP phones that are attached to the local voice gateways should use the local conferencing resources as a first preference and the central site conferencing resources as a secondary choice.

XYZ wants to deploy Fax over IP across its entire network. Hence, voice gateways must support analog ports to connect the fax machines.

Quality of Service

XYZ requires good voice quality with its IPT network. Integrated voice and data networks require an intelligent network infrastructure that can properly interpret the QoS markings set by the IPT endpoints.

The XYZ network does not have QoS enabled currently. The XYZ network requires the following:

The endpoints that can mark real-time frames and packets for QoS

The infrastructure that can give preference to the marked frames

Call Routing

Despite the low cost of national long-distance service charges within the United States, to save costs on the calls made between the offices within the United States, XYZ would like to use the IP-WAN for routing voice calls. The following are the requirements of call routing in the new IPT system:

Calls should be routed via IP-WAN as the first choice, where available, and then via PSTN trunks if bandwidth is not available or a WAN link has failed.

Automatic failover must be provided for all IP-WAN routing.

Within the site, users should use four digits to dial other extensions. Site-to-site dialing also should use four digits.

Tail-End Hop-Off (TEHO) is enabled where legally allowed and bandwidth permits. Transporting voice calls across the existing WAN links requires additional bandwidth. Hence, the proposed IPT system must clearly specify the amount of additional bandwidth required in such cases and provide an optimized solution to conserve it.

Note

In certain countries, transporting the voice call across the IP WAN links to another location before terminating the call on a PSTN is illegal.

The remote sites in each global region must use the local gateways to route the local calls and use the gateways at the central sites as an alternative if the local PSTN connection is not available.

A mechanism must be included to control the number of calls that traverse the IP-WAN considering the traffic utilization on the WAN links.

Classes of restrictions must be provided based on the phone type (e.g., a lobby phone versus an employee phone).

For the initial deployment, branch sites will have a single PRI or multiple PRI circuits where needed. The IPT system must be flexible enough to make new changes and must be easy to troubleshoot.

Emergency Services

All small branch sites have direct connectivity to the PSTN, and the billing number is associated with the street address of each branch site. All the emergency calls need to be routed via the PSTN connections from the branch sites. This avoids the emergency service calls being accidentally routed via the TEHO and connecting to an incorrect public safety answering point (PSAP). All the remote sites have a single T1/E1 PRI connectivity to the PSTN. Where possible, you should provide backup circuits to route the emergency calls if the T1/E1 PRI links are unavailable.

Within the United States, the IPT system must comply with Federal Communications Commission Enhanced 911 (E911) regulations. For more information on E911, go to http://www.fcc.gov/911/enhanced/.

Note

To determine if a particular state's law requires businesses to comply with E911, go to the following website:

http://www.nena9-1-1.org/9-1-1TechStandards/state

Based on this website, the three states in which the U.S. locations resideCalifornia, Texas, and Washingtondo not require businesses to comply with E911.

There are currently no requirements for E911-equivalent functionality in Australia.

IPT Features and Applications

The "Customer Requirements" section, earlier in this chapter, mentioned the limitations of the current voice network infrastructure at XYZ. The management staff of XYZ is looking for an IPT solution that can remove those limitations and provide the following additional features and applications that were not possible with the legacy infrastructure:

Attendant Console Provides a centralized attendant operator for each site that has a web-based GUI that can be used to answer the incoming calls and direct them to the right user within the company.

Manager/Assistant (Boss/Secretary) Feature Allows assistants to receive/transfer calls received for managers. Managers can designate more than one assistant to handle their calls.

IP phone services The following services should be provided:

Corporate directory lookup from IP phones

A corporate directory lookup application allows IP phone users to search against the XYZ corporate Active Directory for a user's phone number. Applications of this type improve employee productivity.

Calendar and other useful services

Multiple line appearances Provides more than one line appearance on the phone and is especially useful for call center agents who need one line that is specifically used for handling incoming customer support calls and another line for making other calls.

Mobility Some users at XYZ frequently travel between the sites, and XYZ company policy encourages telecommuters. The IPT system should enable such users to log in from any phone and personalize the phone with their extension number, speed dials, and other settings. This allows the users to work from any phone and still receive the calls as if they were at their desk phone.

Help desk support for 25 agents XYZ requires the IPT application that provides Automated Call Distribution (ACD), wherein the external/internal callers are directed to the right skill group agent to handle the customer support calls for the following two groups:

Internal IT help desk group

Customer support group

IP SoftPhone support for mobile users A SoftPhone is an application that is installed on a user's computer/laptop and emulates the real IP phone. This type of application is especially useful for mobile users because they can carry the phone with them.

Conferencing support Currently, XYZ uses an external provider to provide the conference bridge services. With the deployment of IPT, XYZ wants to deploy self-manageable conferencing resources that can support up to ten participants per conference call and that enables conference calls to be scheduled and managed via a web-based GUI.

Security

With the integration of voice and data solutions, the call-processing servers and the telephony endpointssuch as gateways, media resource devices, and IP phoneswill be part of the data network. Security plays a critical role in achieving the high availability of the IPT networks. XYZ has the following basic security requirements:

Multiple administration levels for the administrative and operations staff to configure the call-processing servers

Intrusion detection system

Antivirus software support

Logging of user login attempts and configuration changes

Secure call-processing and application servers through the use of firewalls

Redundancy and High Availability

XYZ requires this solution to provide redundancy and fault tolerance at every level. A failure of a server, gateway, gatekeeper, switch, or any other critical resource should not affect end users. The failure must be transparent to end users.

The IPT solution should provide 99.999 percent uptime for all the IPT devices and infrastructure.

Network Management

XYZ has a global network operations center (NOC) located in San Jose that monitors all the existing networking devices. XYZ is looking for a complete network management solution to monitor the IPT components covering all the following aspects:

Fault management

Configuration management

Accounting

Performance management

Security management

Change management

Return on Investment

ROI analysis takes into account cost of technology ownership and the strategic value of the IT initiative. For effective maximization of ROI, you need to understand how your overall cost of network ownership (voice, video, and data) will be lower in a converged environment. You have to compare the cost of implementing a converged environment to the cost of having a separate voice, video, and data network infrastructure, which includes expenses for separate IT groups for voice, video, and data networks; license renewal fees for your legacy voice systems; expenses for moves, adds, and changes; and other overhead.

According to a study conducted by Sage Research, Inc. for Cisco Systems (to download the "Sage IPT Productivity Study" presentation, go to http://www.cisco.com/partner/cnic/presentations.shtml), 75 percent of the survey respondents believed that cost savings is the main reason to move to a converged network, whereas 65 percent feel that employee productivity gains is the key driver motivating companies to deploy IPT.

XYZ, similar to other companies, is looking to save costs and at the same time recognizes the potential for a converged network to improve employee productivity, enable new application capabilities, and potentially drive revenues.

Tip

A detailed white paper, "The Strategic and Financial Justification for IP Communications," is available to provide senior network engineers and managers with the factual support to justify a strategic and financial decision to invest in a converged voice, video, and data network.

This white paper is available for download from http://www.cisco.com/partner/cnic/roi.pdf.