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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
continued...
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…
continued...
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.
continued...
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.
continued...
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