University:
California State University, Northridge
Course:
COMP 322/L | Introduction to Operating Systems and System Architecture and Lab
Academic year:

2024
Views:

353

Pages:

29
Author:

jbroieduroseba4

Voice over IP How 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   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        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 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 – What is it?  Voice over Internet Protocol  Introduction of VoIP in 1995 by Vocaltec Inc. VoIP – 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 – Standards 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 – Applications 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 – Applications 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 – Applications 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 – Applications A third application of VoIP software is inter-working with cellular networks. VoIP – Applications Other applications: • e-commerce – multi-service applications (call button) • conferencing systems that may include shared screens, whiteboarding, etc Marketing application for Venetian VoIP – Pro 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 – Pro and Cons VoIP – Pro and Cons Quality-of-service (QoS) issues • Delay problems: echo, talker overlap and jitter • Too many standards VoIP – Pro and Cons VoIP – Security Issues  Transmissions  Unauthorized use Solution for transmission issue  Check Point Software  Aravox  Nortel Networks  Aspect Communication Security - Check 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 - Aravox 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 use Use a personal identification number  Restrict employees dialing access  Track phone calls  Employee monitoring  Gateways eliminate crank calls and telemarketers  Other Solution VPN  VPN hardware and software installation  Use this over WAN  Offers high strength encryption keys  Protect both data and the networks  The 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 Distance Pick up phone  Dial  Long distance provider  Pay connection fee and per minute charge  Billed monthly  VoIP Long Distance Pick up phone  Dial number  VoIP provider  Internet  Receiver’s VoIP provider  This eliminate large phone bill  VoIP - Demonstration 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 - Expected 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

Voice over IP

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