internet network for o level
-
Upload
samit-singh -
Category
Education
-
view
25 -
download
0
Transcript of internet network for o level
![Page 1: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/1.jpg)
CHAPTER - 4
INTERNET NETWORK
![Page 2: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/2.jpg)
Network
• A computer network is simply a group of computers that are so connected that resources can be shared and information can be exchanged.
• exchange information • share resource
• wired & wireless
![Page 3: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/3.jpg)
Need of Networking
• Resource sharing• Reliability• Financial benefits• Better communication medium• Access to remote database
![Page 4: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/4.jpg)
Types of Networks
• Local Area Network (LAN)• Metropolitan Area Network (MAN)• Wide Area Network (WAN)• Value-Added Network (VAN)• Backbone• Campus Area Network (CAN)• Home Area Network (HAN)• Wireless/Mobile Networks
![Page 5: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/5.jpg)
Local Area Network
• within a room/floor/building/organization• usually less than 1 km in diameter
![Page 6: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/6.jpg)
Advantages of LAN
• sharing of expensive resources such as color laser printers• high-speed exchange of essential information between key people in an organization• increase the range of potential applications• increase productivity and profitability
![Page 7: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/7.jpg)
Disadvantages of LAN
• financial cost of networking hardware• requires memory space in each computer• complex• lack of control• security system must be implemented in order to protect confidential data• memory intensive programs(RDBMS) are particularly vulnerable to networking because of memory requirement
![Page 8: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/8.jpg)
Characteristics of LAN
• restricted geographical area• relatively high speed than WAN• private networks
• e.g. Computer Lab
![Page 9: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/9.jpg)
Metropolitan Area Network
• larger than LAN but smaller than WAN• e.g. cable TV networks
![Page 10: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/10.jpg)
Characteristics of MAN
• 5-50 KM• generally not owned by a single organization (biz. purpose)• large companies/universities with multiple buildings• acts as a high-speed network to allow sharing of regional resources
![Page 11: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/11.jpg)
Wide Area Network
• nationwide or worldwide (public network)• it may also enable LANs to communicate with each other
![Page 12: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/12.jpg)
Characteristics of WAN
• ensure high-quality, reliable service for end users• separate each user’s session• use public transmission media such as telephone lines, microwave link and satellite links
![Page 13: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/13.jpg)
Functions of WAN
• Remote data entry
• Centralizing information
• Facilitating communications
![Page 14: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/14.jpg)
Types of WAN
• Hierarchical Networks : configure computers in a hierarchy (client-server)
• Distributed Data-processing Networks : peer-to-peer
![Page 15: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/15.jpg)
Nodes
• A node is any device connected to a computer network. • Nodes can be computers, personal digital assistants (PDAs), cell phones, or various other network appliances.
![Page 16: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/16.jpg)
Host/Server
• The most powerful type of computer on the network, that does all the processing for the user.
![Page 17: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/17.jpg)
Workstation
• It is a personal computers on network that is operated by network users. • Each workstation process its own files using its own operating system.
![Page 18: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/18.jpg)
Bandwidth• refers to the difference between the highest and lowest frequencies of a transmission channel • In networking, bandwidth or throughput defines the net bit rate (bit/s, kbit/s, Mbit/s, Gbit/s, etc.)
![Page 19: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/19.jpg)
Broadband vs. Baseband•Bandwidth can be divided into channels thus channel is simply a portion of bandwidth that can be used for transmitting data.two ways of allocating the capacity of bounded transmission media are:Baseband & Broadband. •Transmission use entire bandwidth for single channel.• Allow the division of bandwidth into multiple channels.
![Page 20: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/20.jpg)
Interoperability• Network Interoperability is the continuous ability to send and receive data between interconnected networks providing the level of quality expected by the end user customer.
![Page 21: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/21.jpg)
Network Administrator• an individual that is responsible for the maintenance of computer hardware and software systems that make up a computer network• generally mid-level support staff within an organization and do not typically get involved directly with users
![Page 22: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/22.jpg)
Functions of Network Admin• Initial network planning• Frequency allocation, predetermined traffic routing to support load balancing• Cryptographic key distribution authorization• Configuration management• Fault management• Security management• Performance management• Bandwidth management• Accounting management
![Page 23: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/23.jpg)
Network Management• a service that employs a variety of tools, applications and devices to assist human network managers in monitoring and maintaining networks• There exist a wide variety of software and hardware products that help in managing a network by sending them alerts when they recognize problems.• Upon receiving these alerts, management entities are programmed to react by executing operator notification, event logging, system shutdown and/or automatic attempts at system repair• Simple Network Management Protocol (SNMP)
![Page 24: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/24.jpg)
Network Security• Physical Security Holes : unauthorized physical access
• Software Security Holes : privileged software
• Inconsistent Usage Holes : When a system administrator assembles ineffective hardware and software such that the system is seriously flawed from a security point of view
![Page 25: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/25.jpg)
Protection Methods• Authorization : access only those resources they are authorized• Authentication : username & password• Encrypted Smart Cards : Punch card • Biometric Systems : Thumb impression, retina eyes• Firewall : Protection Layer1. Packet Filter2. Application Gateway3. Circuit-level Gateway4. Proxy Server
![Page 26: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/26.jpg)
Network Components
Chassis
![Page 27: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/27.jpg)
RepeaterRegenerates and propagates all electrical
transmissions between 2 or more LAN segmentsAllows extension of a network beyond physical length
limitationsLayer 1 of the “OSI model”
HigherLayers
Physical
HigherLayers
PhysicalPhysicalRepeater
Network A Network B
![Page 28: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/28.jpg)
Repeater
![Page 29: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/29.jpg)
Bridge/Hub/SwitchConnects 2 or more LAN segments and uses data link
layer addresses (e.g.MAC addresses) to make data forwarding decisions
Copies frames from one network to the otherLayer 2 of the “OSI model”
Bridge/Hub/Switch
Physical 1 Physical 2
Data Link Data Link
HigherLayers
Physical
HigherLayers
Physical
Data Link23-01-88-A8-77-45
Data Link53-F1-A4-AB-67-4F
Node in Network A Node in Network B
![Page 30: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/30.jpg)
Switch & Router
![Page 31: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/31.jpg)
RouterConnects 2 or more networks and uses network layer
addresses (like IP address) to make data forwarding decisions
Layer 3 of the “OSI model”
Router
A node in Network B
HigherLayers
Physical
HigherLayers
PhysicalPhysical 1
Data Link
Physical 2
Data Link Data Link
A node in Network A
Data Link
Network145.65.23.102
Network137.22.144.6 Network Network
![Page 32: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/32.jpg)
Gateway/TunnelConnects 2 or more networks that can be of different
types and provides protocol conversion so that end devices with dissimilar protocol architectures can interoperate
Gateway
137.22.144.6
145.65.23.102
Netware
TCP/IP
![Page 33: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/33.jpg)
Gateway
![Page 34: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/34.jpg)
Probe• Remote Network MONitoring : to monitor the LAN
![Page 35: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/35.jpg)
RSM & Terminal Server• Router Switch Module(RSM): A router installed as a card in a switch to perform routing between VLANs
• Terminal Server: A specialized system that connects terminals to a network
![Page 36: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/36.jpg)
Logical Devices• A Digital Field Meter(DFM) monitors logical devices to diagnose power supply, resource and temperature exceptions.
• Fan• Temperature Sensor• Processor• Memory• Power Supply• Voltage Sensor
![Page 37: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/37.jpg)
Network Adapters• A logical or physical component of a network device that connects the device to a network.
• Port: A port has a MAC address but no IP address
• Interface: It may have a MAC address, an IP address, or both.
![Page 38: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/38.jpg)
Logical Links(Virtual LAN)• VLANs are logical links managed by DFM.
• VLAN is a logical subgroup within LAN that is created by software rather than by manually moving cables in the wiring closet.
![Page 39: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/39.jpg)
Client/Server Model • Two parts: Client & Server
![Page 40: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/40.jpg)
Client/Server Model • A client is a single-user workstation running front-end software that knows how to communicate with the server.
• A server is one or more multi-user processors with shared memory.
• Clients rely on servers for services.
![Page 41: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/41.jpg)
Advantages of Client/Server Model • It facilitates the use of graphical user interface(GUI) available on powerful workstations.
• It allows the acceptance of open systems because of the fact that clients and servers can be running on different hardware and software platforms.
![Page 42: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/42.jpg)
Disadvantages of Client/Server Model • If a significant portion of application logic is moved to a server, the server may become a bottleneck in the processing and distribution of data to the clients.
• The server’s limited resources will be in ever-increasing demand by the increasing number of resource consumers.
![Page 43: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/43.jpg)
Application of Client/Server• Novel’s NetWare Operating System: supports TCP/IP protocol
• Windows NT 4.0: supports TCP/IP, IPX, also includes Internet Information Server (IIS). IIS includes both a web server and an FTP server.
• Windows 2000 Server: supports IP, IPX, AppleTalk
• IBM OS/2 Warp: It does not include an Internet server, but it does have a built-in web browser and FTP client.
![Page 44: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/44.jpg)
File Server Model• In this model, the application and the data reside on the file server.
• When a network user needs access the application and data, both are loaded over network onto that user’s workstation.
• Sending the application and data from the server to the workstation puts load on the network.
![Page 45: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/45.jpg)
File Server Model
![Page 46: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/46.jpg)
Communication Media• There are several types of physical channels through which data can be sent from one point to another in a LAN.
• Bounded/Guided Media (Wired)• Unbounded/Unguided Media (Wireless)
• Media differ in the capability for the following reasons:1. Noise absorption: Susceptibility to external noise2. Radiation: Leakage of signal3. Attenuation: decline of magnitude of signal with
distance4. Bandwidth: transmission speed
![Page 47: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/47.jpg)
Guided Media• Wired media
1. Twisted-pair wire : LAN
2. Coaxial cabling : Cable TV
3. Fiber-optic cabling : Broadband
![Page 48: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/48.jpg)
Twisted-pair wire• two insulated copper wires (1 mm thick)
• The purpose of twisting the wires is to ensure that each wire is equally exposed to any external electrical magnetic field that could induce unwanted noise.
• commonly used in local telephone communication and for digital data transmission over short distances up to 1 km. (9600 bps)
![Page 49: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/49.jpg)
Twisted-pair wire
Insulator (Teflon in Cat 5)
![Page 50: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/50.jpg)
Advantages• being the oldest method, trained manpower is easily available
• In a telephone system, signals can travel several kilometers without amplification
• can be used for both analog and digital data transmission
• least expensive
• if a portion of a twisted-pair cable is damaged, the entire network is not shutdown
![Page 51: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/51.jpg)
Disadvantages• easily picks up noise signals
• thin (break easily)
![Page 52: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/52.jpg)
Types of TP Cable• Category 3 : 4 pairs
• Category 5 : 4 pairs but more twisted with Teflon insulation
• Category 6 : Gigabyte Ethernet
![Page 53: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/53.jpg)
Coaxial Cabling• stiff (rigid) copper wire surrounded by an insulating material• The insulator is encased within a cylindrical conductor (braided mesh)• The signal is transmitted by the inner copper wire
![Page 54: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/54.jpg)
Types of Coaxial Cabling• Two types:
1. 50-ohm : digital transmission2. 75-ohm : analog transmission (Cable TV)
![Page 55: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/55.jpg)
Coaxial Cable Implementation
Terms Implementation
10Base2 Thin Ethernet (RG-58), 10MBPS, 185m cable segment
10Base5 Thick Ethernet, 10MBPS, 500m cable segment(bus)
10BaseF
Fiber-optic cable
10BaseT
UTP, uses RJ-45 connectors, Star Topology, 100m length
Thick Ethernet
0.4 inch thick, 1006m
Thin Ethernet
0.2 inch thick, 165m, normally used for office installation
![Page 56: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/56.jpg)
Advantages• better shielding against EMI(Electromagnetic interference) than twisted-pair cable
• can be used for both analog and digital
• higher bandwidth (noise immunity)
• more expensive than TP but easy to handle
• capable of carrying over 50 std 6MHz color TV channels
![Page 57: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/57.jpg)
Security• Cables that employ copper conductors can easily be breached by listening equipment.
• If the main consideration is security, then fiber cable is the only choice to avoid espionage.
![Page 58: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/58.jpg)
Optical Fiber• newest form of bounded media• superior in data handling and security• transmits light signals rather than electric signals• each fiber has an inner core of glass/plastic that conducts light
![Page 59: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/59.jpg)
Optical Fiber• total internal reflection
![Page 60: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/60.jpg)
Optical Fiber• Two light sources:1. LEDs (Light Emitting Diodes)2. LASERs(Light Amplification by Stimulated Emission
Radiation)
Photoelectric diodes
LED/Laser
![Page 61: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/61.jpg)
Types of Optical Fiber• Two types:1. Single-mode fiber (8-10µ (microns) core)2. Multimode fiber (50µ microns core) 1µ = 10-6 m
Laser
LED
![Page 62: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/62.jpg)
Characteristics• Cost: more expensive than copper cable (associated equipments)• Installation: difficult to install• Bandwidth capacity: provides data rates from 100MBPS to 2GBPS• Node capacity: 75 nodes• Attenuation: much lower attenuation but has a different problem, namely, chromatic dispersion• EMI: immune to eavesdropping • Mode of transmission: half duplex
![Page 63: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/63.jpg)
Chromatic Dispersion
![Page 64: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/64.jpg)
Advantages• handle much higher bandwidth with low attenuation
• not affected by power surges, EMI or power failures
• lighter than copper cable
• do not leak light and are quite difficult to tap (excellent security)
![Page 65: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/65.jpg)
Disadvantages• unfamiliar technology requiring skills
• Being unidirectional, two-way communication requires either two fiber cables or two frequency bands on one fiber
• higher cost
![Page 66: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/66.jpg)
Comparison
Factor UTP STP Coaxial Fiber-optic
Cost Lowest Moderate Moderate Highest
Installation Easy Fairly easy Fairly easy Difficult
Bandwidth 1-155 Mbps 1-155 Mbps 100 Mbps 2 Gbps
Attenuation
High (few hundred meter)
High (few hundred meter)
Lower (few kilometer)
Lowest (tens of kilometer)
EMI Most vulnerable to EMI and eavesdropping
Less vulnerable than UTP
Less vulnerable than UTP
Not affected by EMI or eavesdropping
![Page 67: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/67.jpg)
Unguided Media• signals are not guided through a solid medium (Air)
• Radio wave (including VHF and microwave links)• Satellite links• VSATs(Very Small Aperture Terminals)• Infrared and millimeter waves
![Page 68: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/68.jpg)
Radio Waves• frequencies between 10 KHz and 1 GHz• broadcast omnidirectionally or unidirectionally• The power of the Radio Frequency (RF) signal is determined by the antenna and trans-receiver.
![Page 69: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/69.jpg)
Characteristics• easy to generate• travel long distances• penetrate buildings easily• omnidirectional• At low frequency, radio waves pass through obstacles easily, but the power falls off sharply with distance from source.• At high frequency, radio waves tend to travel in straight lines and bounce off obstacles.• absorbed by rain
![Page 70: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/70.jpg)
Microwave Transmission• Above 100 MHz, the waves travel in straight lines and can, therefore, be narrowly focused.• Concentrating all the energy into a small beam using a parabolic antenna gives a much higher signal to noise ratio, but the transmitting and receiving antennas must be accurately aligned with each other.• uses repeaters at intervals of about 25-30 km to amplify weak signal
![Page 71: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/71.jpg)
Microwave Transmission• do not pass through buildings well• Multipath Fading (delayed waves may arrive out of phase)• The higher the towers are, the further apart they can be.
![Page 72: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/72.jpg)
Characteristics• transmission depends on weather and frequency. (10GHz)• widely used for long-distance telephone communication, cellular telephones, television distribution• inexpensive as compared to fiber-optic system (congested area)• 16 Gbps
![Page 73: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/73.jpg)
Types• Two Types:
1. Terrestrial2. Satellite
![Page 74: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/74.jpg)
Terrestrial Microwave Systems• use directional parabolic antennas to send and receive signals• Relay towers and repeaters are used to extend signals• used whenever cabling is cost-prohibitive such as in hilly areas or crossing rivers etc.
![Page 75: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/75.jpg)
Characteristics• Frequency range : 4-6 GHz and 21-23 GHz• Cost : inexpensive for short distance but expensive for long distance• Installation: difficult due to Line-of-sight requirements• Bandwidth capacity: 1-10 Mbps• Attenuation: affected by atmospheric conditions (rain and fog)• EMI: vulnerable to EMI, jamming and eavesdropping
![Page 76: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/76.jpg)
Satellite Microwave Systems• one antenna is on the satellite in geo-synchronous orbit about 36,000 km above the equator (can reach the most remote places)• the transmitted frequency is different from the receiving frequency to avoid interference
![Page 77: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/77.jpg)
Characteristics• Frequency range: 4-6 GHz and 11-14 GHz• Cost: The cost of building and launching a satellite is extremely high• Installation: extremely technical and difficult • Bandwidth capacity: 1-10 Mbps• Attenuation: depends on frequency, power, antenna size and atmospheric conditions. Higher frequency microwaves are more affected by rain and fog
![Page 78: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/78.jpg)
Advantages and Limitation• visible from any point• transmission and reception costs are independent of the distance• a transmission station can receive its own transmission (testing)
• cost of placing the satellite• a signal sent to a satellite is broadcast to all receivers within the range (security measures need to be taken)
![Page 79: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/79.jpg)
VSATs• Very Small Aperture Terminals (1m wide antennas)• the micro-stations do not have enough power to communicate directly with one another, hence • a special ground station, the hub, with a large high-gain antenna is needed to relay traffic between VSATs
![Page 80: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/80.jpg)
Light Wave Transmission• connect two LANs in two buildings via lasers mounted on their roof-tops• Coherent optical signaling using lasers is inherently unidirectional. So, each buildings needs its own Laser and photo detector
![Page 81: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/81.jpg)
Advantages and Disadvantages• Advantages:1. bandwidth is very high at very low cost2. easy to install3. does not require any license
• Disadvantages:1. cannot penetrate rain or thick fog2. heat from sun causes convection currents
![Page 82: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/82.jpg)
Infrared and Millimeter Waves• used for short-range communication (remote control in TV)• directional, cheap and easy to build but do not pass through solid objects• Security if Infrared systems against eavesdropping is better than that of radio systems• No government license is needed (radio systems must be licensed)
![Page 83: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/83.jpg)
Fiber-optics communication
Factor LED Laser
Data rate Low High
Mode Multimode Multimode or single-mode
Operating distance 3 Km 30 Km
Lifetime Long life Short life
Temperature sensitivity
Minor Substantial
Cost Low Substantial
• Light Source: LED/Laser• Transmission medium: Fiber-optic cable• Detector: converter
![Page 84: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/84.jpg)
Types of Network• Client/Server Computer Network
• Peer-to-peer (P2P) Computer Network
![Page 85: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/85.jpg)
Client/Server• Two-tier architecture• Server accepts client requests, process them and return the requested information to the client.
![Page 86: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/86.jpg)
Client/Server• Characteristics of Client:1. Activates Master Computer2. Initiates requests3. Waits for and receive replies4. Connects to one or more number of servers at one time5. Typically interacts directly with end-users using a GUI
• Characteristics of Server:1. It waits for requests from clients2. Upon receipt of requests, it process them and then
offers replies3. It usually accepts connections from a larger number of
clients.4. It does not interact directly with end-users.
![Page 87: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/87.jpg)
Peer To Peer(P2P) Computer Network Direct system exchange of resources between linked peers in network
The most used in the world
Basically different from the Client-server architecture
• e.g. Telephony Traffic
![Page 88: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/88.jpg)
88
Architecture of P2PPeer to peer is a type of network infrastructure where each computer is both server
and client. In this case, the computers connected to the network share their resources .
• Distributed Architecture • Decentralized architecture
![Page 89: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/89.jpg)
89
P2P Network administration
In a typical peer-to-peer, there is no administrator .So,
each user manages his own post. On the other hand all users
can share their resources as they wish. If we consider one of
the posts as a server, it is intended to share resources, if not it
consumes resources from other posts
![Page 90: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/90.jpg)
Types of P2P• three categories:
1. Collaborative/Distributed computing: Science and Biotech org.
2. Instant messaging: MSN Messenger or AOL (real-time chat)
3. Affinity communities: search other user’s computers for information and files like Napster
4. Napster was the name given to two music-focused online services. It was originally founded as a pioneering peer-to-peer file sharing Internet service that emphasized sharing audio files, typically music, encoded in MP3 format.
![Page 91: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/91.jpg)
Working of P2P• each computer typically runs both client and server software• Once you have downloas and install P2P client, you can log into a Central Indexing Server (indexes all users who are connected to the server means who are online)• P2P client will contain an area where you can search for a specific file.• The utility queries the index server to find other connected users with the requested file.• Once the file download is complete, the connection will be broken.
![Page 92: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/92.jpg)
Addressing in Internet• Each device in a network must have a unique address to be identified.
• two types of addressing schemes:1. IP (Internet Protocol) addressing : 192.168.10.51
2. DNS (Domain Name System) addressing : www.google.com
![Page 93: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/93.jpg)
IP Address
• two version of IP Address:1. IPv4 : 32-bit address2. IPv6 : 128-bit address
0-255 0-255 0-255 0-255
Octet (4)
Period (3)
• two types of IP Address:1. Static IP2. Dynamic IP : DHCP
![Page 94: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/94.jpg)
IPv4 ClassesA, B, C : Mostly used classesD : MulticastE : Broadcast
Class Leftmost bits Start address Finish address
A 0XXX 0.0.0.0 127.255.255.255
B 10XX 128.0.0.0 191.255.255.255
C 110X 192.0.0.0 223.255.255.255
D 1110 224.0.0.0 239.255.255.255
E 1111 240.0.0.0 255.255.255.255
![Page 95: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/95.jpg)
Domain Name System (DNS)• purpose of DNS is to translate domain names into IP addresses
![Page 96: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/96.jpg)
Domain Name System (DNS)• domain name space (tree) is divided into three different sections:
1. Generic domains2. Country domains3. Inverse domains
![Page 97: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/97.jpg)
Generic Domains• define registered hosts according to their generic behavior (3 chr)
Label Description
com Commercial organization
edu Educational institutions
gov Government institutions
int International organizations
mil Military groups
net Network support centers
org Nonprofit organizations
![Page 98: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/98.jpg)
Country Domains• 2 character country abbreviations
Label Description
us USA
in India
uk UK
ca Canada
au Australia
fr France
![Page 99: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/99.jpg)
Inverse Domains• used to map an address to a name (rDNS)
![Page 100: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/100.jpg)
Resolving Names to Addresses• HOSTS.txt was used earlier (managed by Stanford Research Institute International (SRI) • In 1983, Paul Mockapetris introduce the concept of DNS• The root of DNS database on the Internet is managed by the Internet’s Network Information Center (InterNIC).
• The top-level domains were assigned organization wise, and by country.
![Page 101: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/101.jpg)
Workgroup vs Domain• Workgroup (P2P) , Domain (Client/Server)• In a domain, user accounts are defined & managed in a central database (Security Accounts Manager)• By default, each domain is a separate entity and do not share information and resources.• To allow users to access resources in another domain, you need to establish a trust between the two domains.
![Page 102: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/102.jpg)
Network Topologies• Topology is the method in which networks are physically connected together.• It determines the complexity and cost.
• Bus• Ring• Star• Mesh
![Page 103: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/103.jpg)
Bus Topology• simplest & oldest used LAN design (passive topology)• e.g. Ethernet 10Base2 (thinnet)• can be found in Client/Server system
![Page 104: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/104.jpg)
Advantages & Disadvantages• Advantages:1. simple, reliable, easy to use (small-sized LANs)2. requires least amount of cable (less expensive)3. it is easy to extend a bus (connector)
• Disadvantages:1. spend a lot of its bandwidth with the computers
interrupting each other instead of communicating2. difficult to troubleshoot
![Page 105: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/105.jpg)
Ethernet• 1973 by Bob Metacalfe (IEEE standard called 802.3 CSMA/CD)
![Page 106: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/106.jpg)
Collision Domain• a section of a network where data packets can collide with one another when being sent on a shared medium• the larger the collision domain, the more likely it is that collision will occur
![Page 107: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/107.jpg)
CSMA/CD• Carrier Sense Multiple Access with Collision Detection
![Page 108: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/108.jpg)
LocalTalk• a data link protocol built into the Macintosh (Apple computer)
• it forms a part of the AppleTalk protocol suite (provide file and printer sharing services)
• AppleTalk Network Layer
![Page 109: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/109.jpg)
Ring Topology• active network, no termination, each node act as a repeater• can be found in P2P networks
Nearest Active Upstream Neighbor
Nearest Active Downstream Neighbor
![Page 110: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/110.jpg)
Advantages & Disadvantages• Advantages:1. every computer is given equal access to the token2. continues to function in a slower manner rather than
fail completely
• Disadvantages:1. Failure of one computer affects the whole network2. difficult to troubleshoot3. Adding or removing computers disrupts the network
![Page 111: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/111.jpg)
IBM Token Ring• IBM created IEEE 802.5 standard known as Token Ring• it uses a special packet known as Token• Multi-station Access Unit (MSAU)
![Page 112: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/112.jpg)
Fiber Distributed Data Interface(FDDI)• another ring-based network but implemented without hubs• uses multimode fiber-optic cables to implement very fast, reliable networks
![Page 113: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/113.jpg)
Fiber Distributed Data Interface(FDDI)• used as a backbone to connect LANs and computers
![Page 114: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/114.jpg)
Working of FDDI• The possessor of the token is allowed to put a new token onto the ring as soon as it finished transmitting its frames.
Wrapping
![Page 115: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/115.jpg)
Star Topology• Hybrid hub can accommodate several types of cable (Hybrid Star)• e.g. Ethernet 10BaseT• Active Hub(regenerates & require power) and Passive Hub (not req.)
![Page 116: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/116.jpg)
Advantages & Disadvantages• Advantages:1. easier to modify or add new computers2. easy to troubleshoot3. robust4. use several types of cable
• Disadvantages:1. if the central hub fails, the whole network fails to
operate2. cabling cost
![Page 117: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/117.jpg)
Asynchronous Transfer Mode(ATM)• newest topology, can carry voice & data over network wire or fiber• transmits all packets as 53-byte cells • Quality of Service (QoS)• extremely high-speed (25-622Mbps or 2.488Gbps)
![Page 118: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/118.jpg)
Working of ATM• ATM communicates with cells rather than transmitting frames.
• Instead of specifying the source and destination addresses of the stations communicating, an ATM cell indicates the path the data will flow through.
• every station is always transmitting (empty cells)
![Page 119: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/119.jpg)
Mesh Topology• most often used in large backbone networks in which failure of a single switch or router can result in a large portion of a network going down (expensive)
![Page 120: internet network for o level](https://reader038.fdocuments.in/reader038/viewer/2022110315/55ce5978bb61eb70598b4780/html5/thumbnails/120.jpg)
Intranet• a network that connects the computer and networks within an organization by using the hardware and software that is used on the Internet (TCP/IP protocol)
• secure & can have thousands of users
Intranet(HCL)
Intranet(Wipro)Interne
t
Extranet