Spring 2005 A newsletter for business, educators and students in the telecommunications industry

In this issue:

• NCTT's 8^th Annual Curriculum Workshop in July
• Convergence of Voice, Video, and Data
• NCTT Around the Country

---

NCTT's 8^th Annual Curriculum Workshop, July 11 - 14, 2005

Our annual educator-to-educator workshop has incorporated a fresh twist for this year - an open Request For Proposals to Information and Communications Technologies (ICT) faculty members and industry professionals. Not only is the Center tapping into its Regional Partner Network for subject matter expertise, but is also inviting non-partner institutions to participate and share leading-edge ideas with attendees. Some of the proposals received by the time of this publication are not only technologically focused, but also present ideas and methodologies for the application of ICT in dependent industries. Applications are being accepted until May 16, 2005.

This year's workshop will also maintain the features that have made it such a success in the past. Instructional materials will be provided to facilitate bringing new knowledge directly to the classroom. The technical sessions will incorporate hands-on learning techniques in laboratory settings. The grant-writing sessions which were very well received last year are again a part of the agenda.

Submit a proposal or sign-up for the workshop today - space is filling quickly!

Back to top

---

Convergence of Voice, Video, and Data
Ted Chandler, CIS Instructor, Cuyamaca College, California

Introduction

The following article is an adaptation of material used by Prof. Chandler in his on-line Fundamentals of Telecommunications course. It is presented here to offer an overview of the concepts and core technology processes and terminology to consider in this very dynamic time of Information and Communications Technologies (ICT) convergence. It is an example of the type of curricula modules constantly being refined by the NCTT Regional Partner Network utilizing its Open Content Development System. These modules are designed to stand easily alone but allow for customization to any specific classroom or training environment.

Objectives

In this module, you will learn to:

• Identify terminology used to describe applications and other aspects of converged networks
• Describe several different applications available on converged networks
• Outline possible VoIP implementations and examine the costs and benefits of VoIP
• Explain methods for encoding analog voice or video signals as digital signals for transmission over a packet-switched network
• Identify the key signaling and transport protocols that may be used with VoIP
• Understand Quality of Service (QoS) challenges on converged networks and discuss techniques that can improve QoS

Terminology

• Voice over IP (VoIP) - the use of any network (either public or private) to carry voice signals using TCP/IP.
• Voice over frame relay (VoFR) - the use of a frame-relay network to transport packetized voice signal
• Voice over DSL (VoDSL) - the use of a DSL connection to carry packetized voice signals
• Fax over IP (FoIP) - uses packet-switched networks to transmit faxes from one node on the network to another.

Voice Over IP (VoIP)

The use of packet-switched networks and the TCP/IP protocol suite to transmit voice conversations.

Reasons for implementing VoIP may include:

• To improve business efficiency and competitiveness
• To supply new or enhanced features and applications
• To centralize voice and data network management
• To improve employee productivity
• To save money

VoIP and Traditional Telephones

Techniques for converting a telephone signal from digital form include:

• Using an adapter card within a computer workstation.
• Connecting the traditional telephone to a switch capable of accepting traditional voice signals, converting them into packets, then issuing the packets to a data network.
• Connecting the traditional telephone to an analog PBX, which then connects to a voice-data gateway to convert the signals.

VoIP and Traditional Telephones

VoIP and IP Telephones



VoIP and IP Telephones

Popular features unique to IP telephones include:

• Screens on IP telephones can act as Web browsers, allowing a user to open HTTP-encoded pages and, for example, click a telephone number link to complete a call to that number.
• IP telephones may connect to a user’s personal digital assistant (PDA) through an infrared port, enabling the user to, for example, view his phone directory and touch a number on the IP telephone’s LCD screen to call that number.
• If a line is busy, an IP telephone can offer the caller the option to leave an instant message on the called party’s IP telephone screen.

VoIP and IP Telephones

VoIP and Softphones

VoIP and Softphones

Fax over IP (FoIP)

Fax over IP (FoIP)

Fax over IP (FoIP)

Vidoeconferencing

The real-time transmission of images and audio between two locations.

• Video streaming - the process of issuing real-time video signals from a server to a client.
• Video terminals - devices that enable users to watch, listen, speak, and capture their image.
• Multipoint control unit (MCU) - also known as a video bridge, provides a common connection to several clients.

Call Centers

    

Unified Messaging

• A service that makes several forms of communication available from a single user interface.
• The goal of unified messaging is to improve a user’s productivity by minimizing the number of devices and different methods she needs to communicate with colleagues and customers.

VoIP Over Private Networks

VoIP Over Private Networks cont’d

Characteristics that make a business particularly well-suited to running VoIP over a private network include:

• A high number of telephone lines (for example, more than 100)
• Several locations that are geographically dispersed across long distances (for example, over a continent or across the globe)
• A high volume of long-distance call traffic between locations within the organization
• Sufficient capital for upgrading or purchasing new CPE, connectivity equipment, LAN transmission media, and WAN links
• Goals for continued network and business expansion

VoIP Over Public Networks

• To carry packet-based traffic, common carrier networks incorporate the following:
• Access service - provides endpoints for multiple types of incoming connections.
• Media gateway service - Translates between different Layer 2 protocols and interfaces.
• Packet-based signaling - Provides control and call routing.
• Signaling gateway service - Translates packet-based signaling protocols into SS7 signaling protocol and vice versa.
• Accounting service - Collects connection information, such as time and duration of calls, for billing purposes.
• Application service - Provides traditional telephony features to end-users.

VoIP Over Public Networks

VoIP Over Public Networks

Softswitch - is a computer or group of computers that manages packet-based traffic routing and control.

VoIP Over Public Networks

    

Cost-Benefit Analysis

The major costs involved in migrating to and supporting a converged network include:

• Cost of purchasing or upgrading CPE, connectivity devices and transmission media for each location
• Cost of installation services and vendor maintenance
• Cost of training technical employees and other staff
• Recurring cost of new or expanded connections
• Cost of transmitting voice and data, if part of the connection fees are usage-based

Potential economic gains of converged network can be estimated by taking into account the following:

• Bypassing common carriers to make long-distance calls, thus avoiding tolls
• Consolidating traffic over the same connections, which leads to reducing or canceling PSTN or leased-line connections
• Providing employees with more efficient tools and means of communication
• Increased productivity for mobile employees

Waveform Codecs (Coder/De-Coder)

• G.711 - known as a waveform codec because it obtains information from the analog waveform, and then uses this information to reassemble the waveform as accurately as possible at the receiving end.
• G.723 - uses a form of PCM known as differential pulse code modulation (DPCM). In DPCM, the codec samples the actual voice signal at regular intervals.
• DPCM codecs - work well with human speech because, within very short time spans, our speech patterns are predictable.
• Adaptive differential pulse code modulation (ADPCM) - in this codec, not only do the nodes base predictions on previously-transmitted bits, but they also factor in human speech characteristics to recreate wave-forms.

Vocoders

Apply sophisticated mathematical models to voice samples, which take into account the ways in which humans generate speech.

G.729 - reduces its throughput requirements by suppressing the transmission of signals during silences.

• Can operate over an 8-Kbps channel.
• Requires only moderate DSP resources and results in only moderate delays.

Hybrid Codecs

Incorporate intelligence about the physics of human speech to regenerate a signal. Hybrid codecs use lower bandwidth than waveform codecs, but provide better sound quality than vocoders.

One example of a hybrid codec is specified in the ITU standard G.728.

Table 14_1: Voice Encoding Techniques

Standard	Codec Type	Required Throughput	DSP Usage	Voice Quality	Delay
G.711	Waveform (PCM)	64 Kbps	Low	Excellent	Negligble
G.723	Waveform (DPCM)	6.4 Kbps	Moderate	Good	High
G.726	Waveform (ADPCM)	16, 24, 32 or 40 Kbps	Low	Varies; good at highest throughput and bad at lowest	Low
G.728	Hybrid	16 Kbps	High	Good	Low
G.729	Vocoder	8 Kbps	Moderate	Fair	Moderate

H.323

An ITU standard that describes not one protocol, but an entire architecture for implementing multiservice packet-based networks.

• H.225 - the H.323 protocol that handles call signaling.
• H.245 - ensures that the type of information, whether voice or video, issued to an H.323 terminal is formatted in a way that the H.323 terminal can interpret.

Session Initiation Protocol (SIP)

• SIP was codified by the IETF (in RFC 2543) as a set of Session-layer signaling and control protocols for multiservice, packet-based networks.
• Because it requires fewer instructions to control a call, SIP consumes fewer processing and port resources than H.323.
• SIP and H.323 regulate call signaling and control on a VoIP network. However, they do not account for communication between media gateways.

Media Gateway Control Protocol (MGCP) and MEGACO (H.248)

Resource Reservation Protocol (RSVP)

• A QoS technique that attempts to reserve a specific amount of network resources for a transmission before the transmission occurs.
• Allows for two service types: Guaranteed service and Controlled-load service.
• As a result of emulating a circuit-switched path, RSVP provides excellent QoS.
• Because it requires a series of message exchanges before data transmission can occur, RSVP consumes more network resources than some other QoS techniques.

Differentiated Service (Diffserv)

A technique that addresses QoS issues by prioritizing traffic.

DiffServ defines two types of forwarding:

• Expedited Forwarding (EF)
• Assured Forwarding (AF)

Multiprotocol Label Switching

• Offers a different way for routers to determine the next hop a packet should take in its route.
• To indicate where data should be forwarded, MPLS replaces the IP datagram header with a label at the first router a data stream encounters.
• The MPLS label contains information about where the router should forward the packet next.

Table 14_2: PSTN Compared with Packet-based Networks

Charactersitic	PSTN	VoIP
Switching Technique	Citcuit-switched (point-to-point connection for duration of conversation)	Packet-switched (signals are divided into packets that can follow different routes)
Quality of Service	Excellent	Varies: several good options for approaching PSTN quality; no single standard yet; standardization between networks requires cooperation between providers
Ubiquity	Existing network covers virtually all of the United States	VoIP networks are scattered, smaller and less common; some are private, whereas others belong to common carriers
Interoperability	Reliance on a single protocol ensures interoperability between different carriers	Due to different encoding, signaling and QoS protocols, interoperability between networks cannot be assumed; requires cooperation among competitors
Availability	Almost always available (99.999% of the time)	Availability depends on numerous factors and is never guaranteed
Bandwidth Usage	Fixed at 64 Kbps per channel	Variable, from 6.4 Kbps to 64 Kbps per channel; can be specified according to customer's needs and network availability
Flexibility	Proprietary signaling and switching protocols result in dependence on telecommunications carrier for applications and little opportunity for customization	Open access to protocols for signaling allows customers and developers to devise custom applications; requires significant technical skill to customize
Cost	Potentially more expensive because of its relatively high bandwidth requirements and dependence on proprietary signaling and switching	Potentially less expensive due to bandwidth conservation; but also introduces cost of new hardware, software and work requirements

Summary

• VoIP can improve efficiency and competitiveness, supply new or enhanced features and applications, and centralize voice and data network management.
• Fax over IP (FoIP) is commonly implemented according to either the ITU T.37 or T.38 standard.
• Call centers are good candidates for converged networks.
• Codecs convert analog voice signals into digital form.

Back to top

---

NCTT Around the Country

NCTT and its members will be attending or presenting at numerous conferences around the country this year. Please take the time to look us up at the following events.

Workshops hosted by NCTT Regional Partners:

May 16 - 20
Working Connections IT Faculty Development Institute

Hosted by NCTT Regional Partner Collin County Community College, Frisco, TX

• Faculty discussions with key IT managers from leading corporations in Texas
• Networking sessions for faculty to share best techniques in IT education
• Presentations on the Pedagogy of IT by nationally recognized authors

NCTT Co-PI Mike Qaissaunee and colleague Mohammed Shanehsaz are presenting on Wireless Security.
http://conv1.ccccd.edu/course.shtml

---

June 20 - June 22
Mid-Atlantic Institute for Telecommunications Technologies (MAITT) - Brookdale, NJ - College Faculty Workshop

Brookdale Community College will be hosting two (2) workshops (High school dates are below) for both college and high school faculty. Each 2-1/2 day workshop will combine theory and hands-on experience in wireless communications integrated with security. Participants will leave the workshop with curriculum and content in wireless communications and security to incorporate in their own classrooms. Participants will receive a $50 stipend per day as part of their training. This workshop is grant funded by the National Science Foundation.

http://www.maitt.org/events.html

---

June 28 - 30
MAITT - Brookdale, NJ - High School Faculty Workshop

---

July 11 - 14
NCTT's 8^th Annual Curriculum Workshop

See the article at the top of this page.

---

Back to top

---

Workshops Attending/Presenting at:

May 23 - 25
National Conference on High Performance Computing, Knoxville, TN
Deadline: May 1, 2005

The Pellissippi State High Performance Computing Regional Training Center in conjunction with the National Center of Excellence for HPC Technology and the National Science Foundation presents the Third Annual National Conference on High Performance Computing in Knoxville located at the foot of the Great Smokey Mountains.

(NCTT Exec. Dir. Gordon Snyder and Co-PI's, Jim Downing and Michael Qaissaunee presenting)
http://highperformancecomputing.org/events/3nc/index.html

---

June 6 - 9
SUPERCOMM, Chicago

SUPERCOMM is the world's premier annual exhibition and conference for communications service providers and private network managers

Attending: Jim Downing, NCTT and Kris Kersey, Lake Land College
http://www.supercomm2005.com/

---

June 12 - 15
American Society for Engineering Education (ASEE), Portland, OR - "Exploring the World of Engineering Education"

The ASEE Annual Conference and Exposition is the only conference dedicated to all disciplines of engineering education. It is committed to fostering the exchange of ideas, enhancing teaching methods and curriculum, and providing networking opportunities for faculty members, deans, and industry representatives interested in furthering engineering education.

(NCTT Co-PI Mike Qaissaunee and colleague Mohammed Shanehsaz presenting with Ann Beheler, Collin County CC)
http://www.asee.org/about/events/conferences/annual/future/index.cfm

---

July 19 - 22
Boston Area Advanced Technological Education Connections (BATEC) Summer Institute, Boston, MA

(NCTT Co-PI Mike Qaissaunee and colleague Mohammed Shanehsaz are presenting on Wireless Security;
NCTT Webmaster, Scott SaintOnge is conducting a workshop on Information Architecture)
http://www.batec.org

---

August 24 - 26
Society for Applied Learning Technology, Arlington, VA - Washington Interactive Technologies Conference

Presentations will include development, utilization and implementation of new technologies as they relate to: Increased Personnel Effectiveness; Reduced Training Costs; Increased Return on Investment; Reduced Training Time; Reduced Operating and Support Cost; Productivity Gains; Quality Improvement; Advanced Instruction Delivery Capability; Management Information Systems; Decision Support Systems; and Budget Management and Planning.

(Michael Qaissaunee attending)
http://www.salt.org/salt.asp?ss=l&pn=washington

---

October 5 - 7
Advanced Technological Education (ATE) Annual Conference, Washington DC

---

October 23 - 26
Conference on Information Technology, League for Innovations, Dallas TX

The League for Innovation's annual Conference on Information Technology (CIT) offers a diverse program and cutting edge exposition exploring the intelligent application of information technology in community and technical colleges.

Mike Q, NCTT Partner Consultant Pete Saflund & Scott S. are presenting on the NCTT Collaborative Model and Open Content Development System.
NCTT's Nina Laurie and Pete S. are presenting "GIS – Emerging Technology’s Best Kept Secret"
http://www.league.org/2005cit/index.html

Back to top

---

Email List | Publications | Resources | News & Events | About the ICT Center | Search | Home

---

Any opinions, findings and conclusions or recommendations expressed in this material are those
of the author(s) and do not necessarily reflect those of the National Science Foundation.

This material is based on work supported by the National Science Foundation under Grant Number DUE 0302548.

Copyright August 2004 STCC Foundation Press All rights reserved. E-Mail the Webmaster with your comments.

Springfield Technical Community College

The ICT Center c/o STCC, One Armory Square, PO Box 9000, Suite 1, Springfield, MA 01102-9000
(413) 755-6550 (phone) | (413) 755-6325 (fax)