Unit 2 : Networking
Lesson 01 - Role of Networks
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
What is a Network?
▪ Many types of network provide different kinds of services.
▪ In the course of a day,
▪ A person might make a phone call,
▪ Watch a television show,
▪ Listen to the radio,
▪ Look up something on the Internet or
▪ Even play a video game with someone in another country.
▪ All of these activities depend on robust, reliable networks;
What is a Network?
A Computer Network is a collection of autonomous computing devices that are interconnected in various ways in order
to exchange information by common conventions, called protocols, over a shared communication medium.
Note: A single computer system with its peripherals such as printers, scanners etc. is not considered as a network.
In computer networking,
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The generic term node or host refers to any device on a network (usually refers to a computer)
Data transfer rate
▪ The speed with which data is moved from one place on a network to another
Data transfer rate is a key issue in computer networks
Advantages of computer networks
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Share Information and Resources
Access databases
Ecommerce
Easy administration
Communication
Provides data security
Benefits of a Network
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Information sharing
Hardware sharing
Software sharing
Collaborative environment
Risks of Network Computing
▪ The security of a computer network is challenged everyday by:
 Equipment malfunctions
 System failures
Note: equipment malfunctions and system failures may be caused by natural disasters such as floods, storms or
fires and electrical disturbances.
 Computer hackers
 Virus attacks
Factors to be considered when installing a network
1. Performance
2. Reliability
3. Security
Performance
▪It can be measured in following ways:
➢Transit time: It is the time taken to travel a message from one device to another.
➢Response time: It is defined as the time elapsed between a request and response.
▪Other ways to measure performance are:
➢Efficiency of software
➢Number of users
➢Capability of connected hardware
Reliability
▪It decides the frequency at which network failure take place. More the failures are, less is the network's reliability.
Security
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It refers to the protection of data from the unauthorized user or access.
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While travelling through network, data passes many layers of network, and data can be traced if attempted.
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Hence security is also a very important characteristic for Networks.
Lesson [02] System Types
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Network Models
▪ Computer networks can logically classified into two models.
1. Peer to Peer model
2. Client server model
Peer to Peer network
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In a peer to peer network, a number of workstations are connected together for sharing devices, information
or data. All the workstations are considered equal.
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A peer to peer network has no dedicated servers. Any one computer can act as client or server at any instance.
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This network is ideal for small networks where there is no need for dedicated servers, like home networks and
small business networks.
Client server network
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In a server-based network, the server is the central location where users share and access network resources .
This dedicated computer controls the level of access that users have to shared resources. Shared data is in one
location, making it easy to back up critical business information. Each computer that connects to the network is
called a client computer.
Server operating systems are designed to handle the load when multiple client computers access server-based
resources.
Network types
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Networks are classified in different types based on purpose and/or size.
 LAN
 MAN
 WAN
 PAN (Personal Area Network)
 SAN (Storage Area Network)
 CAN (Controller Area Network)
 VPN (Virtual Private Network)
Local Area Networks (LANs)
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A Local Area Network spans across a small geographic area
LANs are usually confined to one building or a group of buildings
Usually privately owned
Provides high data rates
The most common type of Local Area Network is called Ethernet
Wide Area Networks (WANs)
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A network which covers a very large geographical area such as a country, continent or even the world
Provides long distance communication of data or information
Operating at low speeds (compared to LANs)
Metropolitan Area Network (MAN)
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A network which covers medium geographical area such as a town or a city.
Provides high speed connectivity for Internet through DSL/ ADSL lines and other services such as cable TV.
Virtual Private Network (VPN)
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A Virtual Private Network (VPN) is a network that uses a public telecommunication infrastructure, such as the
Internet, to provide remote offices or individual users with secure access to their organization’s network.
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Became popular as more employees worked in remote locations. • Employees can access the network
(Intranet) from remote locations.
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The Internet is used as the backbone for VPNs.
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Reduces cost tremendously from reduction of equipment and maintenance costs.
Storage Area Networks (SANs)
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A Storage Area Network (SAN) is a high-speed special purpose network (or sub network) that interconnects
different kinds of data storage devices with associated data servers.
Controller Area Network (CAN)
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Controller Area Network is a serial bus network of microcontrollers that connects devices, sensors and
actuators in a system or sub-system for real-time control applications.
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It is a dedicated development of the automotive electronics industry
Other types of Networks
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Intranet – An intranet is a private LAN designed to use by everyone within an organization.
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Protected from unauthorized external access by means of a network gateway and firewall
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May be created simply by using private IP address ranges such as 192.168.0.0/16
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Extranet – a network that connects people within your company with people who are outside your company.
All within a secure, password protected network that can be accessed from anywhere.
What is Cloud Computing?
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Cloud computing is the delivery of on-demand computing services -- from applications to storage and
processing power -- typically over the internet and on a pay-as-you-go basis.
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Elastic resources—Scale up or down quickly and easily to meet demand
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Metered service - So you only pay for what you use
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Self-service —AlltheIT resourcesyouneed with self-serviceaccess
Types of Cloud Services
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Most cloud computing services fall into three broad categories:
1. Software as a service (SaaS)
2. Platform as a service (PaaS)
3. Infrastructure as a service (IaaS)
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These are sometimes called the cloud computing stack, because they build on top of one another.
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Knowing what they are and how they’re different makes it easier to accomplish business goals.
Software as a service (SaaS)
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Cloud-based applications or software as a service run on distant computers “in the cloud” that are owned and
operated by others and that connect to users’ computers via the internet and, usually, a web browser.
Platform as a service (PaaS)
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Platform as a service provides a cloud-based environment with everything required to support the complete
lifecycle of building and delivering web-based (cloud) applications without the cost and complexity of buying
and managing the underlying hardware, software, provisioning, and hosting
Infrastructure as a service (IaaS)
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Infrastructure as a service provides companies with computing resources including servers, networking,
storage, and data center space on a pay-per-use basis.
Lesson [03] Networking Standards
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪ LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Networking Standards- Introduction
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A Standard is an agreed upon definition of a protocol.
Standards are industry wide protocol definitions that are not tied to a particular manufacturer.
Many organizations are involved in setting standards for networking
Networking Standards
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The five most important organizations are:
 American National Standards Institute (ANSI)
 Institute of Electrical & Electronics Engineers (IEEE)
 International Organization for standardization (ISO)
 Internet Engineering Task Force (IETF)
 WorldWideWeb Consortium (W3C)
IEEE
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The Institute of Electrical and Electronic Engineers (IEEE) is a global association and organization of
professionals working toward the development, implementation and maintenance of technologycentered products and services.
IEEE is a nonprofit organization founded in 1963.
It works solely toward innovating, educating and standardizing the electrical and electronic
development industry.
IEEE 802 Standards
• In 1985,the computer society of the IEEE started a project called , Project 802,to set standards to enable
intercommunication among equipment from a variety of manufactures .
• Instead , it is away of specifying functions of the physical layer and the data link layer of major LAN protocols.
Conceptual Models – Introduction
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TCP/IP and OSI are hierarchical models to define how network devices and their applications follow
protocols that have a set of rules to communicate with each other, similar to Human Laws such as
country’s Constitution
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Open System Interconnection (OSI) model is a conceptual model that covers all aspects of network
communications.
This model characterizes and standardizes the internal functions of a communications system by
partitioning it into abstraction layers.
This is a model that allows any two different systems to communicate regardless of their underlying
architecture (hardware or software).
OSI Model
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TCP/IP Model
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TCP (Transmission Control Protocol) /IP (Internet Protocol) was developed by the Department of Defense (DoD)
project agency.
Unlike OSI Model, it consists of four layers each having its own protocols. Internet Protocols are the set of rules
defined for communication over the network.
The TCP/IP model is mostly used for interconnecting computers over the internet.
TCP/IP Model Layers
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Application Layer: This layer permits users to access the services of global or private internet. Some protocols
described in this layer are TELNET,SMTP ,FTP. The working of this layer is a combination of application,
presentation and session layer of the OSI model.
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Transport Layer: It enables a fault-free end-to-end delivery of the data between the source and destination
hosts in the form of datagrams. The protocols defined by this layer are TCP and UDP.
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Internet Layer: The purpose of this layer is to transmit an independent packet into any network which travels
to the destination. It includes the IP , ICMP and ARP as the standard packet format for the layer.
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Network Interface Layer: This layer acts as an interface between hosts and transmission links and used for
transmitting datagrams.
Lesson [04] Networking Topologies
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
What is a Topology?
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A network topology describes the physical connections and logical communication pathways between objects
in a network.
The term is used to describe a variety of networking concepts.
Topologies are used to describe connections between computers (or hosts) in a network, between routers in a
network, or even between wide area network connections.
There are two types of topologies.
✓Physical
✓Logical
Physical Topology
• A Physical Topology describes the way in which the devices are connected.
Bus Topology
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In Bus topology, all devices share single communication line or cable.
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Bus topology either uses CSMA/CD technology or recognizes one host as Bus Master to solve the issue while
multiple hosts sending data at the same time.
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A failure of a device does not affect the other devices. But a failure of the shared communication line can make
all other devices stop functioning.
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Both ends of the shared channel have a line terminator.
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The data is sent in only one direction and as soon as it reaches the extreme end, the terminator removes the
data from the line.
Ring Topology
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In ring topology, each host machine connects to exactly two other machines, creating a circular network
structure.
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When one host tries to communicate or send message to a host which is not adjacent to it, the data travels
through all intermediate hosts.
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To connect one more host in the existing structure, the administrator may need only one more extra cable.
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Failure of any host results in failure of the whole ring. Thus, every connection in the ring is a point of failure.
There are methods which employ one more backup ring.
Star Topology
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One of the most common network setups where each of the devices and computers on a network connect to a
central hub.
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If the central hub fails, the entire network becomes unusable.
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Star topology is not expensive as to connect one more host, only one cable is required and configuration is
simple.
Tree Topology
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Also known as Hierarchical Topology, this is the most common form of network topology in use presently.
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This topology imitates an extended Star topology and inherits properties of bus topology.
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This topology divides the network in to multiple levels/layers of network
Mesh Topology
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In this type of topology, a host is connected to one or multiple hosts.
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This topology has hosts in point-to-point connection with every other host or may also have hosts which are in
point-to-point connection to few hosts only.
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Mesh technology comes in two types:
 Full Mesh - All hosts have a point-to-point connection to every other host
 Partial Mesh - Not all hosts have a point-to-point connection to every other host
Logical Topology
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The Logical Topology describes how the devices communicate or the shape of the communication
path.
Ethernet
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Ethernet is a widely-deployed LAN technology.
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This technology was invented by Bob Metcalfe and D.R. Boggs in the year 1970. It was standardized in IEEE
802.3 in 1980.
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Ethernet shares media. A Network which uses shared media has high probability of data collision.
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Ethernet uses Carrier Sense Multi Access/Collision Detection (CSMA/CD) technology to detect collisions.
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When a collision occurs in Ethernet, all its hosts roll back, wait for some random amount of time, and then
re-transmit the data.
Ethernet
• An Ethernet connector is a network interface card equipped with 48-bits MAC address.
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Traditional Ethernet uses 10BASE-T specifications.
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10BASE-T Ethernet provides transmission speed up to 10MBPS and uses coaxial cable or Cat-5 twisted pair
cable with RJ-45 connector.
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Ethernet follows star topology with segment length up to 100 meters.
Fast Ethernet
• To encompass the need of fast emerging software and hardware technologies, Ethernet extends itself as Fast
Ethernet.
• It can run on UTP, Optical Fibre, and wirelessly too.
• It can provide speeds up to 100 MBPS. This standard is named as 100BASE-T in IEEE 803.2 using Cat-5 twisted
pair cable.
Gigabit Ethernet
• After being introduced in 1995, Fast-Ethernet could enjoy its high-speed status only for 3 years till Gigabit
Ethernet was introduced.
• Giga-Ethernet provides speeds up to 1000 Mbps.
• IEEE802.3ab standardized Gigabit Ethernet over UTP using Cat-5, Cat-5e and Cat-6 cables.
VLAN
• AVLAN (virtual LAN) is a sub network which can group together collections of devices on separate physical local
area networks (LANs).
• VLANs make it easy for network administrators to partition a single switched network to match the functional
and security requirements of their systems without having to run new cables or make major changes in their
current network infrastructure.
VLAN
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In this diagram, different VLANs are depicted in different colour codes.
Hosts in one VLAN, even if connected on the same Switch cannot see or speak to other hosts in different
VLANs.
To route packets between two different VLANs a Layer-3 device such as a Router is required.
Lesson [5] Network Protocols
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
What is a Network Protocol?
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Network protocols are sets of established rules that determine how to format, transmit and receive data
between two or more devices.
Standardized network protocols provide a common language for network devices.
To successfully send and receive information, devices on both sides of a communication exchange and follow
an agreed protocol
Layer Protocols
A number of applications have been standardized to operate on top of TCP/IP Model.
File Transfer Protocol (FTP)
• The File Transfer Protocol (FTP) is used to send files from one sys
text and binary files are accommodated.
• FTP uses a client - server architecture.
• Files can be transferred between two computers using a FTP software
• FTP software may have a GUI or support a series of commands
Hypertext Transfer Protocol (HTTP)
• The Hypertext Transfer Protocol (HTTP) is an application layer protocol that is used by the World Wide Web
and this protocol defines how messages are formatted and transmitted.
• Computers on the WWW use HTTP to talk with each other
• HTTP is a connectionless text based protocol
• HTTPS is used for secure browsing
Simple Mail Transfer Protocol (SMTP)
• The Simple Mail Transfer Protocol (SMTP) provides a basic electronic mail transport facility for transferring
messages among separate hosts.
• SMTP is an application level protocol.
• SMTP is a connection oriented protocol.
• SMTP is a text based protocol.
• It handles exchange of messages between e-mail servers over a TCP/IP network
Transmission Control Protocol (TCP)
• TCP provides communication between an application program and the Internet Protocol ▪Responsible for
verifying the correct delivery of data from client to server
• Break data up into packets that the network can handle efficiently
• TCP is a connection-oriented and reliable protocol
• TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and
completely received.
User Datagram Protocol (UDP)
• It is an unreliable and connectionless protocol
• UDP doesn’t have the error checking and ordering functionality of TCP
• UDP is commonly used in time-sensitive communications such as voice and video conferencing or DNS lookups
where occasionally dropping packets is better than waiting.
Lesson [6] Network Protocols – Part 2
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Layer Protocols
A number of applications have been standardized to operate on top of TCP/IP Model.
Internet Protocol (IP)
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Stands for Internet Protocol and it is responsible for logical addressing, path determination and delivering
packets from the source host to the destination host by looking at the IP addresses in the packet headers.
The identifier used in the IP layer of the TCP/IP model to identify each device connected to the Internet is called
the Internet address or IP address
IP has 2 versions: IPv4 and IPv6
IPv4 Introduction
• An IP address is a 32-bit address that uniquely and universally defines the connection of a host or a router to
the Internet. IP addresses are unique
• The 32-bit IP address is broken up into 4 octets, which are arranged into a dotted-decimal notation scheme.
• An octet is a set of 8 bits.
• The address space of IPv4 is 232 or 4,294,967,296.
IP Address Classes
• IP addresses are divided into 5 classes, each of which is designated with the alphabetic letters A to E.
• Classes A, B, and C provide unicast addresses.
• Class D addresses are used for multicasting.
• Class E addresses are reserved for testing & some mysterious future use.
IP Address Classes
IP Address Classes
Are you the Host or the Network
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The 32 bits of the IP address are divided into Network & Host portions, with the octets assigned as a part of one
or the other.
Each Network is assigned a network address & every device or interface (such as a router port) on the network
is assigned a host address.
Class A Addresses
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Class A IP addresses use the 1st 8 bits (1st Octet) to designate the Network ID.
The 1st bit which is always a 0, is used to indicate the address as a Class A address & the remaining 7 bits are
used to designate the Network.
The other 3 octets contain the Host ID
A has a total of: 27-2= 126 networks(0.0.0.0 and 127.x.y.z are special address) 224 – 2 = 16,777,214 hosts
(2n) = Number of networks
(2n –2) = Number of available hosts
Class B Addresses
• Class B addresses use the 1st 16 bits (two octets) for the Network ID.
• The last 2 octets are used for the Host ID.
• The 1st 2 bits, which are always 10, designate the address as a Class B address & 14 bits are used to designate
the Network. This leaves 16 bits (two octets) to designate the Hosts.
• Class B has a total of: 214 = 16384 network address 216 – 2 = 65534 host address
Class C Addresses
• Class C addresses use the 1st 24 bits (three octets) for the Network ID & only the last octet for Host ID.
• The 1st 3 bits of all class C addresses are set to 110, leaving 21 bits for the Network ID. This leaves 8 bits to
designate the Hosts.
• Class C has a total of:
 221 = 2097152 network address
 28 – 2 = 254 host address
Public and Private IP
• A public IP address is an IP address that your home or business router receives from your ISP.
• A private IP address is an IP address that's reserved for internal use
Subnet Mask
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A subnet mask is a number that defines a range of IP addresses that can be used in a network.
A subnet mask hides, or "masks," the network part of a system's IP address and leaves only the host part as the
machine identifier.
The subnet masking process was developed to identify & extract the Network part of the address.
A subnet mask, which contains a binary bit pattern of ones & zeros, is applied to an address to determine
whether the address is on the local Network. This is known as the ANDing process
If it is not, the process of routing it to an outside network begins.
255.255.255.0
Masking concept
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aIn order to get the network address we AND the destination address with the subnet mask ▪ The only way you
can get a result of a 1 is to combine 1 & 1. Everything else will end up as a 0
Default Subnet Mask
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The default subnet masks are three subnet masks that correspond to the standard Class A, B, and C address
assignments.
Trial Separation
• If a destination IP address is 206.175.162.21, we know that it is a Class C address & that its binary equivalent is:
11001110.10101111.10100010.00010101
• We also know that the default standard Class C subnet mask is: 255.255.255.0 and that its binary equivalent is:
11111111.11111111.11111111.00000000
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When these two binary numbers (the IP address & the subnet mask) are combined using Boolean Algebra, the
Network ID of the destination network is the result:
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The result is the IP address of the network. 11001110.10101111.10100010.00000000 206.175.162.0
If this address is the same as the local network, the message is for a node on the local network.
Address Resolution Protocol (ARP)
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An internet layer protocol that is used to convert an IP address into a physical address(MAC address).
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A host wishing to obtain a physical address broadcasts an ARP request onto the network.
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The host on the network that has the IP addresses in the request replies with its physical address.
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There is also Reverse ARP (RARP) which can be used by a host to discover its IP address. In this case, the host
broadcasts its physical address and a RARP server replies with the host’s IP address.
Address Resolution Protocol (ARP)
Lesson [07] Networking Devices
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Network Interface Card (NIC)
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Hubs
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NIC is a computer hardware component that connects a computer to a computer network.
This works in Physical layer.
A hub interconnects two or more workstations into a local area network.
When a workstation transmits to a hub, the hub immediately resends the data frame to all connecting links.
Three basic types of hubs :
 Passive
 Active
 Intelligent
Switch
• Switch is a computer networking device that connects devices together on a computer network by using packet
switching to receive, process, and forward data to the destination device.
• Managed and Unmanaged Switches
Bridge
• A device that connects two local-area networks (LANs), or two segments of the same LAN that use the same
protocol, such as Ethernet or Token-Ring
• Information only cross the bridge if they are addressed for a host on the other side (selective forwarding).
• No hosts on Segment B will receive information from host to host communication on Segment A as they will be
blocked by the bridge.
Router
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A router is a device that forwards data packets along networks.
A router is used to connect at least two networks, commonly two LANs or WANs or a LAN and its ISP's network.
Routers are located at gateways, the places where two or more networks connect.
Routers are the critical devices that keep data flowing between networks and keep the networks connected to
the Internet.
Repeater
• A network device used to regenerate or replicate a signal. Repeaters are used in transmission systems to
regenerate analog or digital signals distorted by transmission loss. Digital repeaters can reconstruct a signal to
near its original quality.
• Works in physical layer.
Access Point
• An access point can be considered to represent a two-port bridge
Modem
• It converts or "modulates" an analog signal from a telephone or cable wire to digital data (1s and 0s) that a
computer can recognize.
• Similarly, it converts digital data from a computer or other device into an analog signal that can be sent over
standard telephone lines. ▪Modem stand for "Modulator-Demodulator."
Content Filter
• Content-control software is software designed to restrict or control the content a reader is authorized to
access.
Firewall
• System or group of systems that enforces an access control policy between two networks
• Monitors and controls traffic into and out of secure networks
• Normally located at the gateway to a network
Load Balancer
• Load balancing improves the distribution of workloads across multiple computing resources, such as
computers, a computer cluster, network links, central processing units, or disk drives.
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Load Balancing algorithms
 Round robin
 Weighted round robin
 Least connections
 Least response time
Packet Shaper
• The Packet Shaper is a device that sits in between the campus network and the outside network.
• All incoming and outgoing traffic passes through it.
VPN Concentrator
• A VPN concentrator is a type of networking device that provides secure creation of VPN connections and
delivery of messages between VPN nodes.
Lesson [08] Transmission Media & Networking Software
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
What is Transmission Media ?
• Transmission media is the data signal carrier with in computer networks.
Basic Types of Physical Media
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Twisted Pair – 10 Base T
Unshielded Twisted Pair (UTP) cable
Shielded Twisted Pair (STP) cable
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Coaxial cable
 Thin Coaxial Cable – 10 Base 2
 Thick Coaxial Cable – 10 Base 5
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Optical Fiber
Twisted Pair Cable
• Inexpensive
• Susceptible to electrical interference (noise)
• Used in telephone systems
• Physical characteristics
 Requires two conductors
 Twisted around each other to reduce electrical interference
 Plastic sheath
• Two Types ▪
 Unshielded Twisted Pair (UTP)
 Shielded Twisted Pair (STP)
UTP vs STP
Coaxial Cable
• At one time, coaxial cable was the most widely used network cabling
• Coaxial was relatively inexpensive, and it was light, flexible, and easy to work with
• It was so popular that it became a safe, easily supported installation
Fiber Optic Cable
• Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials
• Transmit light rather than electronic signals which eliminating the problem of electrical interference.
• Ability to transmit signals over much longer distance.
• Data transmission at vastly greater speeds
Wireless Media
• Microwave system
 transmits data via high-frequency radio signals through the atmosphere
• Satellite system
 receive transmitted signals, amplify them, and then transmit the signals to the appropriate
locations
• Cellular technology
 uses antennae resembling telephone towers to pick up radio signals within a specific area
(cell)
• Infrared technology
 Transmits data as infrared light waves from one device to another, providing wireless links
between PCs and peripherals.
Networking Software
• Network software encompasses a broad range of software used for design, implementation, and operation
and monitoring of computer networks.
• Enables users to have access to network resources in a seamless manner
• Allows administrations to add or remove users from the network
• Helps administrators and security system to protect the network from data breaches, unauthorized access
and attacks on a network
• Enables network virtualizations
Client Software
• Software that resides in a user's desktop or laptop computer or mobile device that accesses a service made
available by a server
• E.g Outlook-Email Client Software
Server Software
• Server software is a type of software that is designed to be used, operated and managed on a computing
server.
• It provides and facilitates the harnessing of underlying server computing power for use with an array of
high-end computing services and functions.
 E.g. Server Operating System
Lesson [09] Server Types
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Servers
• A server is a computer designed to process requests and deliver data to other (client) computers over a
local network or internet.
• Computer networks support one or more servers that handle specialized tasks.
• Server OS is the software that handle those task.
Common Types of Servers
• Web Servers
• Email Server
• FTP Server
• Identity Server
• Proxy Server
• Game Server
• Application Server
Web Servers
• A web server is a computer system that processes requests via HTTP, the basic network protocol used to
distribute information on the World Wide Web.
• Software: Apache HTTP server, Nginx, Internet information server, Apache tomcat
Email Server
• An e-mail server is a computer within your network that works as your virtual post office.
• A mail server usually consists of a storage area where e-mail is stored for local users
Types of mail Server
• Mail servers can be broken down into two main categories: outgoing mail servers and incoming mail
servers.
• Outgoing mail servers are known as SMTP, or Simple Mail Transfer Protocol, servers.
• Incoming mail servers come in two main varieties. IMAP and POP3, or Internet Message Access Protocol,
Post Office Protocol, version 3,
• Servers always store copies of messages on servers.
File Server
• File server is a computer attached to a network that provides a location for shared disk access.
• Shared storage of computer files (such as text, image, sound, video) that can be accessed by the
workstations that are able to reach the computer that shares the access through a computer network.
Database Server
• A database server is a computer program that provides database services to other computer programs or
to computers, as defined by the client–server model.
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Software : MySQL, Oracle Database,IBMDB2, MariaDB
Virtualization Server
• Server virtualization is the process of using software on a physical server to create multiple partitions or
"virtual instances" each capable of running independently.
Server Selection
• Match the server to your primary needs
• Consider about the affordability
• Choose best of the breed
• Buy the right OS
• Build in expansion and redundancy
• Support and maintenance
Workstations
• A workstation is a computer designed for professional use by a single user
• It usually has more capacity than a personal computer, but is not as high-powered as a mainframe
computer that is designed to support very complex calculations and multiple users
Lesson [10] Understanding User Requirements
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Building a good network
• STEP 1 – Verify business goals and technical requirements
• STEP 2 – Determine the features and functions required to meet the identified needs
• STEP 3 – Perform a network readiness assessment
• STEP 4 – Design a solution and site acceptance test plan
• STEP 5 – Create a project plan
Fundamental Design Goals
• Availability
• Security
• Scalability
• Manageability
Network Design Methodologies
• Large network design projects are normally divided into three distinct steps:
 Step 1. Identify the network requirements.
 Business goals
 Technical requirements

 Step 2. Characterize the existing network. Step 3. Design the network topology and solutions
Quality of Service (QoS)
• Capability of a network to provide better service to selected network traffic over various technologies.
• QoS helps manage packet loss, delay and jitter on your network infrastructure.
QoS Characteristics
• Reliability – Lack of reliability means losing a packet or ack
• Delay – Different applications can tolerate delay in different degrees
• Jitter – The variation in packets belonging to same flow
• Bandwidth – Different applications need different bandwidths
Lesson [11] Networking services and application
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Static vs. Dynamic IP Addressing
• Two methods of assigning and IP address to a device.
• When a device is assigned a static IP address, the address does not change.
• Most devices use dynamic IP addresses, which are assigned by the network when they connect and change
over time.
Dynamic Host Configuration Protocol (DHCP)
• A protocol for assigning dynamic IP addresses to devices on a network.
• With dynamic IP addressing, a device can have a different IP address every time it connects to the network.
• In some systems, the device’s IP address can even change while it is still connected.
• DHCP also supports a mix of static and dynamic IP addresses.
DHCP Functions
Domain Name System (DNS)
• A Domain Name System (DNS) server performs the task of mapping a domain name to an IP address.
Network Address Translation (NAT)
•
•
A method of remapping one IP address space into another by modifying network address information in IP
header of packets while they are in transit across a traffic routing device.
The technique was originally used as a shortcut to avoid the need to readdress every host when a network was
moved.
Network Address Translation (NAT)
Lesson [12] Device Configuration
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Practical
• Windows Server 2012 R2 installation on Oracle VirtualBox.
• IP address configuration on client PC.
Lesson [13] Verification, Monitoring and Maintenance
Module Learning Outcomes
▪LO1. Examine networking principles and their protocols.
▪LO2. Explain networking devices and operations.
▪LO3. Design efficient networked systems.
▪LO4. Implement and diagnose networked systems.
Network Verification - Ping Command
•
•
•
Helps to verify the network connectivity.
Used to test the reachability of a host on an Internet Protocol (IP) network.
Ping operates by sending Internet Control Message Protocol (ICMP) echo request packets to the target host
and waiting for an ICMP echo reply.
>ping www.google.com
Network Verification – Traceroute Command
•
Used to show several details about the path that a packet takes from the computer or device you're on to
whatever destination you specify.
> tracert www.google.com
Telnet & SSH Commands
•
•
•
TCP/IP protocol for accessing remote computers.
Through Telnet, an administrator or another user can access someone else's computer remotely.
A program for logging into a remote machine and for executing commands on a remote machine.
Network Monitoring
•
Network monitoring is the use of a system that constantly monitors a computer network for slow or failing
components and that notifies the network administrator in case of outages or other trouble.
•
Network monitoring is part of network management.
•
Eg: Solar Winds Network Performance Monitor, PRTG Network Monitor
Network Monitoring Software
Network Maintenance
• Regular maintenance of the networked systems helps them to run more smoothly as well as reduce the risk of
break downs.
• By having a well-designed maintenance schedule assists you in organizing your maintenance tasks
Network Maintenance Tasks
• Server Management
• Router Management
• Upgrading Hardware and Software
• Network Monitoring
• Network Security
• Scheduling Backups