Networking Fundamentals
Introducing LAN
A network is the interconnection of computers located at different places. It is both software & hardware. The hardware consists of cables and interfaces that connect personal computers and peripherals together. The software manages the files and communication system.
A network is most clearly defined as a "Communication System" because it lets you communicate with other users, share files and share peripherals.
Different Computer Networks
• A typical network includes mainframes, personal computers, and a variety of other computers and communication devices.
• Computer networks fit the general definition of networking since they share electronic data and computing services.
• Computer networks are often classified by size, distance covered, or structure.
Even though the distinctions are rapidly fading, the following network classifications are commonly used:
Local area network (LAN)
Wide Area network (WAN)
• Computer networks fit the general definition of networking since they share electronic data and computing services.
• Computer networks are often classified by size, distance covered, or structure.
Even though the distinctions are rapidly fading, the following network classifications are commonly used:
Local area network (LAN)
Wide Area network (WAN)
Local Area Network
A local area network (LAN) refers to a combination of computer hardware and transmission media that is relatively small.
LANs normally do not exceed tens of kilometers in size and tend to use only one type of transmission medium.
In addition, a LAN is normally entirely contained within a building or campus.
In addition, a LAN is normally entirely contained within a building or campus.
Wide Area Network
A wide area network (WAN) includes all networks larger than a LAN.
WANs interconnect LANs which may be at opposite sides of a country or located around the world.
WANs interconnect LANs which may be at opposite sides of a country or located around the world.
Computing Models and Network Development
• Computer networking technologies have developed because of the requirements of the following computing models :
Centralized computing
Distributed computing
Collaborative computing
Centralized computing
Distributed computing
Collaborative computing
Centralized Computing
• Mainframes, were used to store and organize data. People entered data on mainframes using "local" devices called terminals. A terminal incorporated an input device, such as a keyboard, with some communication hardware so that a single mainframe could service requests from multiple remote individuals.
• The long distance connections between terminals and mainframes do not involve a computer network. In centralized computing, the mainframe provides all the data storage and computational abilities while the terminal is simply a remote input/output device. Computer networks were created when organization began to require that mainframes share information and services with other mainframes.
Distributed Computing
• As the computer industry matured, smaller personal computers were created that allowed individuals total control over their own computer. This personal computing power resulted in a new computing structure called Distributed Computing.
• Instead of centralizing all computers processing into a single mainframe, distributed computing uses multiple smaller computers to achieve the same processing goals. Separate computers work on a subset of tasks without relying upon a single computer for processing. To compete with centralized computing, distributed computing uses computer networking to share the vast amount of information and services available from each distributed computer.
• Instead of centralizing all computers processing into a single mainframe, distributed computing uses multiple smaller computers to achieve the same processing goals. Separate computers work on a subset of tasks without relying upon a single computer for processing. To compete with centralized computing, distributed computing uses computer networking to share the vast amount of information and services available from each distributed computer.
Collaborative Computing
• A new model called collaborative computing (also called cooperative processing) is becoming an important trend. Collaborative computing is a synergistic type of distributed computing where networked computers actually share processing abilities. Instead of simply communicating data between computers, collaborative computing uses two or more computers to accomplish the same processing task.
Network Architecture
Computer networks may be classified according to the Network Architecture
as:
Peer-to-Peer Networks
Peer-to-peer networks allow any entity to both request and provide network services. Peer-to-Peer network software is designed so that peers perform the same or similar functions for each other.
Server-Centric Networks
Server-centric networks involve strictly defined roles. By definition, a server centric network places restrictions upon which entity may make requests or service them. Currently, the most popular personal computer networks are Server-Centric.
Network Elements
• Network elements include hardware, software and protocols. The interrelationship of this basic element constitutes the infrastructure of the network.
• Networks are comprised of four basic elements:
Network Services
Transmission Media
Protocols
Networking Devices
• Network services are the capabilities that networked computers share.
• The term service provider refers to the hardware and software combination that fulfils a specific service role. You should realize that computers and other network devices may provide different services or fill multiple roles simultaneously. A service provider is not a computer; it is a subset of the computer's software and hardware.
• In the computer industry, a distinction is often made between the following three types of service providers and requester:
Servers
Clients
• These entities are differentiated by what they are allowed to do on the network:
Servers are only allowed to provide services.
Clients are only allowed to request services from others.
Peers may do both concurrently.
• Networks are comprised of four basic elements:
Network Services
Transmission Media
Protocols
Networking Devices
• Network services are the capabilities that networked computers share.
• The term service provider refers to the hardware and software combination that fulfils a specific service role. You should realize that computers and other network devices may provide different services or fill multiple roles simultaneously. A service provider is not a computer; it is a subset of the computer's software and hardware.
• In the computer industry, a distinction is often made between the following three types of service providers and requester:
Servers
Clients
• These entities are differentiated by what they are allowed to do on the network:
Servers are only allowed to provide services.
Clients are only allowed to request services from others.
Peers may do both concurrently.
Common Network Service
• Computer applications require some combination of data, processing power, and input/output resources to accomplish their tasks. Network services allow computers to share these resources using special network applications.
• Often, many of the applications that provide network services are combined into a single Network Operating System (NOS).
• When choosing a Network Operating System, pay special attention to which network services you need, this subsection defines the following common network services:
File services
Print services
Message services
Application services
Database services
• Each subsection provides a basic definition of each service and presents the functions and other aspects associated with the service.
File Services
• File services include network applications designed to efficiently store, retrieve, or move data files.
File services perform the following: read, write, access control, and data management.
• Network file services help you: Rapidly move files from place to place.Use storage hardware efficiently. Manage multiple copies of the same file.
Back up critical data.
File transfer
File storage and data migration
File update synchronization
File archiving
File services perform the following: read, write, access control, and data management.
• Network file services help you: Rapidly move files from place to place.Use storage hardware efficiently. Manage multiple copies of the same file.
Back up critical data.
File transfer
File storage and data migration
File update synchronization
File archiving
Print Services
• Print services are network applications that control and manage access to printers. Fax machines, and copy equipment.
• Network print services help you to:
Reduce the number of printers your organization needs.
Place printers wherever is most convenient.
Queue print jobs to reduce the time your computer spends sending a print job.
Share specialized printers efficiently.
Computerize the transmission and reception of fax images.
Provide multiple access from limited interfaces.
Eliminate distance constraints.
Handle simultaneous requests and queue those requests.
Share specialized equipment.
• Network print services help you to:
Reduce the number of printers your organization needs.
Place printers wherever is most convenient.
Queue print jobs to reduce the time your computer spends sending a print job.
Share specialized printers efficiently.
Computerize the transmission and reception of fax images.
Provide multiple access from limited interfaces.
Eliminate distance constraints.
Handle simultaneous requests and queue those requests.
Share specialized equipment.
Message Services
• Message services include storing, accessing, and delivering text, binary, graphic, digitized video, and audio data. Message services deal with communication between computer users, user applications, network applications, and documents.
Network Message Services
Network message services help you:
Pass computer-generated notes and files between users.
Integrate electronic mail with voice mail systems.
Operate object-oriented software with objects distributed throughout the network.
Route and share data using workflow and linked-object document applications.
Organize and maintain user and device information directories.
Pass computer-generated notes and files between users.
Integrate electronic mail with voice mail systems.
Operate object-oriented software with objects distributed throughout the network.
Route and share data using workflow and linked-object document applications.
Organize and maintain user and device information directories.
Network Applications Services
• Applications services are network services that run software for network clients. They are different from file services because they allow computers to share processing power, not just share data.
• Network application services Coordinate hardware and software to run utilities (or software applications) on the most appropriate platform. Increase the capabilities of key hardware without upgrading every computer on the network.
Specialization of servers
Scalability and growth.
Network Database Services
• Network database services provide service-based database (data or information) storage and retrieval that allow network clients to control, manipulate and present data.
• Client-server database applications divide and optimize the tasks involved in requesting ad proving data.
• Network database services:
• Optimize the computers which store, search, and retrieve database records.
• Control where data is stored geographically.
• Organize data logically between organizational departments.
• Provide data security.
• Reduce database-client access time.
• Coordinating distributed data
• Replication Pathway for Communication
Transmission Media
Transmission media is the pathway networked entities use to contact each other.
Computer transmission media includes cable and wireless technologies that allow networked devices to contact one another.Transmission media can not guarantee that other network devices will understand a message. It can, however, guarantee a message delivery path. Pathway for Communication
Computer transmission media includes cable and wireless technologies that allow networked devices to contact one another.Transmission media can not guarantee that other network devices will understand a message. It can, however, guarantee a message delivery path. Pathway for Communication
Protocols
Protocols are the rules required to help entities communicate or understand each other. A protocol can be one rule or a complete set of rules and standards that allow different devices to hold conversations.
Networking Devices
Networking devices are components used to connect computers or other electronic devices together so that they can share files or resources like printers or fax machines.
The list of networking devices that will be covered in this chapter is given below
Network Interface Card (NIC)
Hub
Switch
Wireless access point (AP)
Router
The list of networking devices that will be covered in this chapter is given below
Network Interface Card (NIC)
Hub
Switch
Wireless access point (AP)
Router
Network Interface Boards
• A network interface board includes all the circuitry needed to create the necessary physical and logical connections between your computer, or other device, and the transmission medium.
• A network interface board is a logic board you install in a computer to connect it to a cable’s connector.
• A network interface card, a portion of the device’s logic board, software of external devices are and a generic hardware port, or a number are all types of network interface boards.
• A network interface board is a logic board you install in a computer to connect it to a cable’s connector.
• A network interface card, a portion of the device’s logic board, software of external devices are and a generic hardware port, or a number are all types of network interface boards.
Hubs
• Hubs receive transmissions from connected devices and transmit the signals to the other connected devices. The hub organizes the cables and transmits incoming signals to the other media segments.
• Some network implementations require a central point of connection between media segments. These central points are referred to as hubs, multiport repeaters, or concentrators. Cables from network devices plug in to the ports on the hub.
Hubs Functionality
Hub is a multiport repeater
Typically used in networks with star topology
Hubs are known as concentrators
Hub works at the 1st or Physical layer of OSI Model
In Case of hub bandwidth is shared not switched
Hub is a single broadcast domain
Hub is a single collision domain
Collision Domain: Two or more devices sharing the same bandwidth are
said to be in a single collision domain.
Broadcast Domain: A broadcast domain is a logical part of a network (a
network segment) in which any network equipment can transmit data
directly to other equipment or device without going through a routing
device
• Some network implementations require a central point of connection between media segments. These central points are referred to as hubs, multiport repeaters, or concentrators. Cables from network devices plug in to the ports on the hub.
Hubs Functionality
Hub is a multiport repeater
Typically used in networks with star topology
Hubs are known as concentrators
Hub works at the 1st or Physical layer of OSI Model
In Case of hub bandwidth is shared not switched
Hub is a single broadcast domain
Hub is a single collision domain
Collision Domain: Two or more devices sharing the same bandwidth are
said to be in a single collision domain.
Broadcast Domain: A broadcast domain is a logical part of a network (a
network segment) in which any network equipment can transmit data
directly to other equipment or device without going through a routing
device
Switch
• A LAN Switch is a centralized device connected to multiple PC or nodes. It is a data link (layer 2) device and read data frames unlike hub.
• It is quiet intelligent to understand the mac-address of the PC or nodes and stores into a repository called CAM table or mac-address-table.
• It has the capability to do a unicast unlike the hub.
• Every switch port is made up of a special hardware called ASIC (Application Specific Integrated Circuit) an integrated embedded hardware that has a capability of switching millions of packets per second with many more features including buffering of data.
• It is quiet intelligent to understand the mac-address of the PC or nodes and stores into a repository called CAM table or mac-address-table.
• It has the capability to do a unicast unlike the hub.
• Every switch port is made up of a special hardware called ASIC (Application Specific Integrated Circuit) an integrated embedded hardware that has a capability of switching millions of packets per second with many more features including buffering of data.
Switch Functionality
• Switch is a multiport bridge
• Switch works at the Data Link Layer of OSI Model
• In case of switch bandwidth is switched not shared
• Switch is a single broadcast domain
• Switch break collision domain into multiple collision domains
• Switch works at the Data Link Layer of OSI Model
• In case of switch bandwidth is switched not shared
• Switch is a single broadcast domain
• Switch break collision domain into multiple collision domains
Wireless access point (AP)
A wireless access point (AP) allows the mobile users or wireless devices to connect to a wired network without physical wire links via radio frequency technologies.
• A wireless access point (AP) is a data-link layer device that contains both a transceiver for wireless communications and a jack for connection to a LAN using twisted pair or fiber-optic cable.
• After you connect the WAP to a cabled network, wireless devices within the range of the WAP’s transceiver can communicate with systems on the cabled network, using the WAP as a conduit. The result is that the wireless devices function as though they are part of the cabled network.
• A hotspot is a common public application of APs, where wireless clients can connect to the Internet without regard for the particular networks to which they have attached for the moment.
Routers
• Routers connect two or more logically separate networks. Each network is identified by its network address, a logical name assigned to it.
• Each network in an internetwork must be assigned a unique
network address.
• Routers are typically much more processing-intensive than bridges. As a result, their processing speeds (generally measured in packets — or blocks of data — forwarded per second) are not usually as high.
• Routers are capable of much more sophisticated path selection. The decision to buy a bridge or a router hinges on specific requirements and the specific network environment.
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