Voice over IPVoice over IP

Information Systems 311

November 19, 2002

How do computers communicateHow do computers communicate

1968 ARPA created a standard by which these computers could communicate known as TCP/IP.

TCP/IP specifies the details of how computers communicate as well as a set of conventions for interconnecting networks and routing traffic.

TCP/IP is the standard by which computer communicate whether its an internal client/server (little “internet”) or one connects through other networks that spans geographic distance (big “Internet”)

Therefore TCP/IP is the base technology for the Global Internet that connects over 170 million individuals in virtually all populated countries around the world.

Some Differences Some Differences

TCP - transmission control protocol Connection orientated circuit (established connection

between two hosts and exchanges streams of data)

Considered a reliable protocol because it guarantees delivery of data and the order of the packets that its sending.

Down-side – requires constant bandwidth to maintain the connection

TCP/IP layers where split in the seventies to handle larger volumes of information

More More

IP – Internet Protocol Connection-less orientated circuit IP works on the packet level Specifies the format of the packets and the addressing

scheme Consider unreliable – individual packets send by by effort

routing and can arrive out of order. Packets are switched doesn’t require constant bandwidth Benefit IP packets can encapsulated with several types of

information like Voice

TCP/IP work within the Internet ModelTCP/IP work within the Internet Model

The Internet’s 5-Layer Model (top – down hierarchy)  Application: used by application program - the start of the five -

layer process. Transport: establishing end-to-end connections, translates domain

names into numeric addresses, and segments messages (also known as the TCP layer)

Network: responsible for end-to-end addressing and routing, determines destination address if unknown (also known as IP layer)

Data Link: deals with message delineation, error control & network access

 Physical: defines how information will be transmitted through the network

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VoIP – VoIP – DefinitionsDefinitions

What is it?How does it work?Standards involved

VoIP – VoIP – What is it?What is it?

Voice over Internet Protocol

Introduction of VoIP in 1995 by Vocaltec Inc.

VoIP – VoIP – How does it work?How does it work?

Converting the voice signal– ADC (analog to digital)– DAC (digital to analog)

Voice (source) - - ADC - - - Internet - - - DAC - - Voice (dest)

Transmission of voice traffic in packets

VoIP – VoIP – Standards InvolvedStandards Involved

H.323 V.2 – Most widely supported– used for packet based multimedia communication

systems

Media Gateway Control Protocol (MGCP)

Session Initiation Protocol (SIP)

VoIP – VoIP – ApplicationsApplications

VoIP could be applied to almost any voice

communications requirement, ranging from a

simple inter-office intercom to complex multi-point

teleconferencing/shared screen environments.

For example…

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VoIP – VoIP – ApplicationsApplications

A network configuration of an organization with many branch offices (e.g., a bank) that wants to reduce costs and combine traffic to provide voice and data access to the main office.

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VoIP – VoIP – ApplicationsApplications

In this VoIP application, an organization wishes to send voice traffic between two inter-office locations over the packet network and replace the PBXs connections at these locations.

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VoIP – VoIP – ApplicationsApplications

A third application of VoIP software is inter-working with cellular networks.

VoIP – VoIP – ApplicationsApplications

Other applications:

• e-commerce – multi-service applications (call button)

• conferencing systems that may include shared screens, whiteboarding, etc

Marketing application for VenetianMarketing application for Venetian

VoIP – VoIP – Pro and ConsPro and Cons

Benefits of the VoIP technology can be divided into the following four categories:

• Cost Reduction• Simplification - an integrated infrastructure • Bandwidth Consolidation

• Advanced Applications

VoIP – VoIP – Pro and ConsPro and Cons

VoIP – VoIP – Pro and ConsPro and Cons

Quality-of-service (QoS) issues

• Delay problems: echo, talker overlap and jitter

• Too many standards

VoIP – VoIP – Pro and ConsPro and Cons

VoIP – VoIP – SecuritySecurity IssuesIssues

Transmissions

Unauthorized use

Solution for transmission issueSolution for transmission issue

Check Point Software

Aravox

Nortel Networks

Aspect Communication

Security - Security - Check Point SoftwareCheck Point Software

Stateful Inspection of Web services traffic from the network layer to the application layer

Centralized management with SmartCenter

Authentication, authorization and secure sign-on with UserAuthority(TM)

Prioritization of Web services traffic using Check Point's Quality of Service (QoS) solution, FloodGate-1

Security - Security - AravoxAravox

Provides a limitless platform for voice service providers.

E.g. IP Centrex unified messaging, instant conferencing, presence and instant messaging

Aravox was the first company creating a carrier-class real-time IP services gateway enabling backbone carriers, access providers and enterprises to deploy secure, real-time communications on converged networks

Solutions for unauthorized useSolutions for unauthorized use

Use a personal identification numberRestrict employees dialing accessTrack phone callsEmployee monitoringGateways eliminate crank calls and

telemarketers

Other SolutionOther Solution

VPNVPN hardware and software

installationUse this over WANOffers high strength encryption keysProtect both data and the networks

The Telephone NetworkThe Telephone Network

Originally designed for analog communications only.

Today, standard analog telephone service is called POTS (Plain Old Telephone Service).

Modem communications use the telephone network to send digital data.

Modems use carrier waves to send information

Traditional Long DistanceTraditional Long Distance

Pick up phoneDialLong distance providerPay connection fee and per minute

chargeBilled monthly

VoIP Long DistanceVoIP Long Distance

Pick up phoneDial numberVoIP providerInternetReceiver’s VoIP providerThis eliminate large phone bill

VoIP - VoIP - DemonstrationDemonstration

Yahoo Messenger

I will use the Voice Over IP feature of the messenger to Chat

This works world wide for free (except ISP fee)

For this Demonstration will be to Minnesota - approx. 1500 miles away.

VoIP - VoIP - Expected growth and futureExpected growth and future

By 2007 VoIP will account for approx. 75% of the worlds voice services.

Many companies are using VoIP on their managed private networks to save money

Extremely likely the PBX’s will offer IP as and added value service – like IP/PBX phone system

Has fantastic potential for e-commerce applications