MT - Basic Networking Module 1-2-3

MT

Network

A system that connects computers and other devices to share resources and communicate.

End Device

• Also known as a host

• The device where a message originates or is received.

Different Kinds of End Devices:

• Desktop Computer

• Laptop

• Printer

• IP Phone

• Wireless Tablet

• TelePresence Endpoint

Intermediary Device

• Devices such as switches, routers, and firewalls that interconnect end devices and manage data flow.

• Regenerate and retransmit data signals.

• Maintain information about what pathways exist in the network.

• Notify other devices of errors and communication failures.

Different Kinds of Intermediary Devices:

• Wireless Router

• LAN Switch

• Router

• Multilayer Switch

• Firewall Appliance

Medium

• Communication across a network is carried through a ______ which allows a message to travel from source to destination.

• Also known as Media

Media/Medium Types:

• Metal Wires within Cables

• Glass or plastic fibers within cables (fiber-optic cable)

• Wireless transmission

Metal wires within cables

Medium type that uses electrical impulses

Glass or plastic fibers within cables (fiber-optic cable)

Medium type that uses pulses of light.

Wireless transmission

Medium type that uses modulation of specific frequencies of electromagnetic waves.

Network diagrams

• Often called Topology diagrams

• Use symbols to represent devices within the network.

Physical Topology Diagrams

Illustrate the physical location of intermediary devices and cable installation.

Logical Topology Diagrams

Illustrate devices, ports, and the addressing scheme of the network.

Common Types of Networks:

• Small Home Networks

• Small Office/Home Office

• Medium to Large Networks

• World Wide Networks

Small Home Networks

Connect a few computers to each other and the Internet

Small Office/Home Office

Enables computer within a home or remote office to connect to a corporate network

Medium to Large Networks

Many locations with hundreds or thousands of interconnected computers

World Wide Networks

Connects hundreds of millions of computers world-wide– such as the internet

Network Infrastructures vary greatly in terms of:

• Size of the area covered

• Number of users connected

• Number and types of services available

• Area of responsibility

Two most common types of networks:

1. Local Area Network (LAN)

2. Wide Area Network (WAN)

Local Area Network (LAN)

• A network infrastructure that spans a small geographical area, such as a home or office.

• Interconnect End devices in a limited area

• Administered by a single organization or individual.

• Provide high-speed bandwidth to internal devices.

• Are connected to each other using WANs.

Wide Area Network (WAN)

• A network infrastructure that spans a wide geographical area, connecting multiple LANs.

• Interconnects LANs over wide geographical areas.

• Typically administered by one or more service providers

• Typically provide slower speed links between LANs

• May use copper wires, fiber optic cables, and wireless transmissions

Internet

• It is a worldwide collection of interconnected LANs and WANs.

• Not owned by any individual or group.

The following groups were developed to help maintain structure on the internet:

• Internet Engineering Task Force (IETF)

• Internet Corporation for Assigned Names and Numbers (ICANN)

• Internet Architecture Board (IAB)

Intranet

A private network that uses internet technology to share information within an organization.

Extranet

A controlled private network allowing access to partners and vendors to specific data.

Home and Small Office Internet Connections

• Cable

• DSL

• Cellular

• Satellite

• Dial-up Telephone

Cable

• High bandwidth

• Always on

• Internet offered by cable television service providers

DSL

• High bandwidth

• Always on

• Internet connection that runs over a telephone line

Cellular

Uses a cellphone network to connect to the internet

Satellite

• Major benefit to rural areas without Internet Service Providers

• This can provide a connection when a wired solution is not available

Dial-up Telephone

• An inexpensive

• Low bandwidth option using a modem

Businesses Internet Connections

• Dedicated Lease Line

• Ethernet WAN

• Business DSL

• Satellite

Dedicated Lease Line

These are reserved circuits within the service provider’s network that connect distant offices with private voice and/or data networking.

Ethernet WAN

This extends LAN access technology into the WAN.

Business DSL

It is available in various formats including Symmetric Digital Subscriber Lines (SDSL)

The Converging Network

• Carry multiple services on one link including:

  • data

  • voice

  • video

• Can deliver data, voice, and video over the same network infrastructure.

• The network infrastructure uses the same set of rules and standards.

Network Architecture

Refers to the technologies that support the infrastructure that moves data across the network.

There are four basic characteristics that the underlying architectures need to address to meet user expectations:

• Fault Tolerance

• Scalability

• Quality of Service (QoS)

• Security

Fault Tolerance

• Network limits the impact of a failure by limiting the number of affected devices.

• Multiple paths are required for fault tolerance.

• Reliable networks provide redundancy by implementing a packet switched network:

  • Packet switching splits traffic into packets that are routed over a network.

  • Each packet could theoretically take a different path to the destination.

• This is not possible with circuit-switched networks which establish dedicated circuits.

Scalability

• Can expand quickly and easily to support new users and applications without impacting the performance of services to existing users.

• Network designers follow accepted standards and protocols in order to

  make the networks scalable.

Quality of Service (QoS)

• It is the primary mechanism used to ensure reliable delivery of content for all users.

• The router can more easily manage the flow of data and voice traffic.

There are two main types of network security that must be addressed:

1. Network infrastructure security

2. Information Security

Network Infrastructure Security

• Physical security of network devices

• Preventing unauthorized access to the devices

Information Security

Protection of the information or data transmitted over the network

Three goals of network security:

1. Confidentiality

2. Integrity

3. Availability

Confidentiality

Only intended recipients can read the data

Integrity

Assurance that the data has not be altered with during transmission

Availability

Assurance of timely and reliable access to data for authorized users

Network Trends

• Bring Your Own Device (BYOD)

• Online collaboration

• Video communications

• Cloud computing

Bring Your Own Device (BYOD)

• Allows users to use their own devices giving them more opportunities and greater flexibility.

• Means any device, with any ownership, used anywhere.

• Allows end users to have the freedom to use personal tools to access information and communicate using their:

  • Laptops

  • Netbooks

  • Tablets

  • Smartphones

  • E-readers

Collaborate

• Work with others over the network on joint projects.

• Tools including Cisco WebEx gives users a way to instantly connect and interact.

• It is a very high priority for businesses and in education.

Video Communication/Video Calls

• Are made to anyone, regardless of where they are located.

• It is a powerful tool for communicating with others.

• It is becoming a critical requirement for effective collaboration.

Cloud Computing

• Storing and accessing data and applications over the internet instead of local servers.

• Applications can also be accessed using the Cloud.

• Allows businesses to deliver to any device anywhere in the world.

• It is made possible by data centers.

• Smaller companies that can’t afford their own data centers, lease server and storage services from larger data center organizations in the Cloud.

Public Cloud

Cloud services offered over the public internet, available to anyone.

Private Cloud

Cloud services used exclusively by a single organization.

Hybrid Clouds

• Made up of two or more Cloud types – for example, part custom and part public.

• Each part remains a distinctive object but both are connected using the same architecture.

Custom Clouds

• Built to meet the needs of a specific industry, such as healthcare or media.

• Can be private or public.

Security Threats

Potential risks to a network's integrity, confidentiality, and availability.

Different kinds of External Threats:

• Viruses, worms, and Trojan horses

• Spyware and adware

• Zero-day attacks

• Threat Actor attacks

• Denial of service attacks

• Data interception and theft

• Identity theft

Different kinds of Internal Threats:

• Lost or stolen devices

• Accidental misuse by employees

• Malicious employees

Security Solutions

• Security must be implemented in multiple layers using more than one security solution.

• Network security components for home or small office network:

  • Antivirus and anti-spyware software should be installed on end devices.

  • Firewall filtering used to block unauthorized access to the network.

Larger networks have additional security requirements:

• Dedicated firewall system

• Access Control Lists (ACL)

• Intrusion Prevention Systems (IPS)

• Virtual Private Networks (VPN)

Shell

• The user interface that allows users to request specific tasks from the computer.

• These requests can be made either through the CLI or GUI interfaces

Kernel

Communicates between the hardware and software of a computer and manages how hardware resources are used to meet software requirements

Hardware

The physical part of a computer including underlying electronics

Graphical User Interface (GUI)

• Allows the user to interact with the system using an environment of graphical icons, menu, and windows.

• It is more user-friendly and requires less knowledge of the underlying command structure that controls the system

• Examples of these are: Windows, macOS, Linux KDE, Apple IOS, and Android

• Can fail, crash, or simply not operate as specified. For these reasons, network devices are typically accessed through a CLI.

PC operating system enables user to do the following:

• Use a mouse to make selection and run programs

• Enter text and text-based commands

CLI-based network operating system enables a network technician to do the following:

• Use a keyboard to run CLI-based network programs

• Use a keyboard to enter text and text-based commands

• View output on a monitor

Console

A physical management port used to access a device in order to provide maintenance, such as performing the initial configurations.

Secure Shell (SSH)

Establishes a secure remote CLI connection to a device, through a virtual interface, over a network

Telnet

Establishes an insecure remote CLI connection to a device over the network.

Terminal Emulation Programs

• Are used to connect to a network device by either a console port or by an SSH/Telnet connection

• There are several terminal emulation programs to choose from, such as PuTTY, Tera Term, and SecureCRT

User EXEC Mode

• Allows access to only a limited number of basic monitoring commands

• Identified by the CLI prompt that ends with the > symbol

Privileged EXEC Mode

• Allows access to all commands and features

• Identified by the CLI prompt that ends with the # symbol

• To move from User EXEC Mode to Privileged EXEC Mode, use the enabled command

  • Switch> enable
Switch#

Global Configuration Mode

• Used to access configuration options on the device

• To move in and out of Global Configuration Mode, use the configure terminal command

  • Switch# configure terminal
Switch(config)#

• To return to Privileged EXEC mode, use the exit command

  • Switch(config)#exit
Switch#

Line Configuration Mode

• Used to configure console, SSH, Telnet, or AUX access.

• To move in and out of Line Configuration Mode, use the line command followed by the management line type.

  • Switch(config)#line console 0
Switch(config-line)#

• To return to Global Configuration Mode, use the exit command

  • Switch(config-line)#exit
Switch(config)#

Interface Configuration Mode

Used to configure a switch port or router interface

• Switch(config-if)#

Subconfiguration Modes

• To move out of any Subconfiguration Mode to get back to Global Configuration Mode, use the exit command.

  • Switch(config-line)#exit
Switch(config)#

• To return to Privileged EXEC Mode, use the end command or key combination CTRL+Z.

  • Switch(config-line)#end
Switch#

• To move directly from one Subconfiguration Mode to another, type in the desired Subconfiguration Mode command.

  • Switch(config-line)#interface FastEthernet 0/1
Switch(config-if)#

Keyword

This is a specific parameter defined in the operation system

Argument

This is not predefined; it is a value or variable defined by the user

Boldface

Indicates commands and keywords that are entered as shown.

Italics

Indicates an argument for which you supply values

[Square brackets]

Indicate an optional element (keyword or argument)

{Braces}

Indicate a required element (keyword or argument)

Braces and Vertical Line within Square Brackets ( [x {y | z}] )

• Indicate a required choice within an optional element.

• Spaces are used to clearly delineate parts of the command

ping

• The command is ____ and the user-defined argument is the ip-address of the destination device.

• For example, ping 10.10.10.5

traceroute

• The command is __________ and the user-defined argument is the ip-address of the destination device.

• For example, traceroute 192.168.254.254

Communications Fundamentals

Networks can vary in size and complexity. It is not enough to have a connection, devices must agree on “how” to communicate.

Three elements of any Communication

• There will be a source (sender).

• There will be a destination (receiver).

• There will be a channel (media) that provides for the path of communications to occur.

Communications Protocols

• All communications are governed by protocols.

• Protocols are the rules that communications will follow.

• These rules will vary depending on the protocol.

Rule Establishment

• Individuals must use established rules or agreements to govern the conversation.

• The first message is difficult to read because it is not formatted properly. The second shows the message properly formatted:

  

• Protocols must account for the following requirements:

  • An identified sender and receiver

  • Common language and grammar

  • Speed and timing of delivery

  • Confirmation or acknowledgment requirements

Network Protocol Requirements

• Message encoding

• Message formatting and encapsulation

• Message size

• Message timing

• Message delivery options

Message Encoding

• Is the process of converting information into another acceptable form for transmission.

• Decoding reverses this process to interpret the information.

Message Formatting and Encapsulation

• When a message is sent, it must use a specific format or structure.

• Message formats depend on the type of message and the channel that is used to deliver the message.

Message Size

Encoding between hosts must be in an appropriate format for the medium.

• Messages sent across the network are converted to bits

• The bits are encoded into a pattern of light, sound, or electrical impulses.

• The destination host must decode the signals to interpret the message.

Message Timing

Includes the following:

• Flow Control

• Response Timeout

• Access Method

Flow Control

Manages the rate of data transmission and defines how much information can be sent and the speed at which it can be delivered.

Response Timeout

Manages how long a device waits when it does not hear a reply from the destination.

Access Method

Determines when someone can send a message.

• There may be various rules governing issues like “collisions”. This is when more than one device sends traffic at the same time and the messages become corrupt.

• Some protocols are proactive and attempt to prevent collisions; other protocols are reactive and establish a recovery method after the collision occurs.