View
242
Download
1
Category
Preview:
Citation preview
Elements of communication– Source (encoding data before transmission)– Transmission Media (Channel)– Information sent– Rules to control transmitting and receiving – Destination (decoding data after receiving)
Chapter Two : Communicating over the Network
Network Structure
Data is sent across a network in small “chunks” called segments
One channel for different uses (multiplexing)
Network Structure End Devices and their Role in the Network
–End devices form interface with human network & communications network
–Role of end devices: (like IP Phone, PC, Printer…)
• client
• server
• both client and server
Network Structure Devices In Between (Routers, Switches)
– Provides connectivity between end devices
– Manages data flow
– Retransmit data
Network Structure
Network media (types, criteria for choosing)This is the channel over which a message travels
UTP (Unshielded Twisted Pair)
Twisting provide : 1- protection against crosstalk, noise generated by adjacent pairs & 2- cancellation of the magnetic field.
Based on connection layout, 3 types of UTP are existed:
Straight UTP Cable
Side1 : WO O WG B WB G WBr Br
Side2 : WO O WG B WB G WBr Br
Cross-Over UTP CableSide1 : WO O WG B WB G WBr BrSide2 : WG G WO B WB O WBr Br
Roll-Over UTP CableSide1 : WO O WG B WB G WBr BrSide2 : Br WBr G WB B WG O WO
Roll-Over Cable consists of RJ-45 on one end & DB-9 on the other end. Conversion adapter from RJ-45 to DB-9 can be used with RJ-45 / RJ-45 Roll-over cable.
Straight UTP Cable : Communicate between dissimilar devices (PC+Hub, PC+Switch, Switch+Router,)
Cross–Over UTP Cable : Communicate between similar devices (PC+PC, Hub+Switch, Router+Router, PC+Router)
Using of UTP Cables
Factors for choosing Network Media
Resistance to Electromagnetic Interference (EMI)
Attenuation
Cost
Installation
Security
Which cable has the highest attenuation? Coax, UTP, Fiber
Network Types
Local Area Networks (LANs)- A network serving a home, building or campus is considered a Local Area Network (LAN) : Single Organization
Network Types
Wide Area Networks (WANs)- LANs separated by geographic distance are connected by a network known as a Wide Area Network (WAN)
Function of Protocol in Network Communication
Network protocols are usedto allow devices to
communicate
successfully
Function of Protocol in Network Communication
Different protocols and how they interact
Protocols are hardware independent
Using Layers to describe net communication
The net communication is a very complex process, if we looked at it as a whole. A simple way to understand this process is to break down the total net communication system into a series of layers. Each layer is responsible for a specific part of net comm.
ISO (International Organization for Standardization)
OSI/RM (Open System Interconnection) → 1984
It provided venders with a set of standards that insured greater compatibility between Net Tech. It has 7 numbered layers
L1 : Physical, L2 : Data Link, L3 : Network, L4 : Transport, L5 : Session, L6 : Presentation, L7 : Application
Advantages of Layering
• Simple to develop
• Simple to maintain
• Simple to learn (understand)
Layers 7, 6, 5 deal with application
Layers 4, 3, 2, 1 deal with data transport
TCP/IP (Transmission Control Protocol / IP Protocol) This model is a suite of more than 10 protocols, distributed on 4 layers : Application, Transport, Internet & Network Access
Name , number & briefly explain the layers of OSI model ?
1. Physical Layer : Binary Transmitting.
2. Data Link Layer : Physical Addressing.
3. Network Layer : IP Addressing.
4. Transport Layer : Reliable Communication.
5. Session Layer : Application Programs Communication.
6. Presentation Layer : Data Representation.
7. Application Layer : Application Programs Assisting.
Layers with TCP/IP and OSI Model
Encapsulation :– Identify data pieces of the sent msg– Ensure data pieces are transmitted to the destination– Enable reassembling data pieces
EncapsulationApplication, Presentation, Session → DataTransport → SegmentsNetwork → PacketsData Link → FramesPhysical → Bits (Encoding)
Addressing and Naming Schemes
Labels in encapsulation headers are used to manage communication in data networks
MAC in layer 2 ; Physical Add ; Device Add
IP in layer 3 ; Logical Add
Port No. in layer 4 : identify service (application)
PC Identifiers (Computer Name, Host Name, IP Add, MAC Add)
Computer Name : 256 characters (unique inside only , non standard)
Host Name : 256 characters (always unique , standard)
IP Address : 4 bytes (always unique , standard)
MAC Address : 6 bytes (always unique , standard)
Which company supports computer name in communication?
Recommended