Network Devices and Host Roles

Data Communications

• Communication rivals air, water, food, and shelter in importance.
• Communication enables a world without boundaries, fostering global and human networks.

Intermediary Network Devices

• These devices interconnect end devices and manage data flow.
• Examples include switches, wireless access points, routers, and firewalls.
• Intermediary responsibilities include:
  • Regenerating and retransmitting data signals.
  • Maintaining network pathway information.
  • Notifying devices of communication errors.
  • Directing data flow along alternate paths if links fail.
  • Classifying and prioritizing messages.
  • Permitting or denying data flow based on security settings.

Host Roles

• Hosts participate directly in network communication.
• Servers provide information using software to end devices, common types are:
  • Email servers.
  • Web servers.
  • File servers.
• Clients send requests to servers to retrieve information. Example common types are:
  • Web browsers.
  • Email.

Server Types

• Email servers run email software, clients access using appropriate clients.
• Web servers run web server software, clients access using web browsers.
• File servers store files, client devices access these files.

Types of Connection

• Peer-to-peer networks suit very small networks for end-to-end communication.
• Peer-to-peer advantages include ease of setup, simplicity, low cost, and usefulness for tasks such as transferring files and sharing printers.
• Peer-to-peer disadvantages are lack of centralized administration, security issues, scalability limitations, and slower performance.

End Devices

• An end device is the source or destination of a message.
• Data originates within the end device.

Network Media

• Network communication occurs across a medium from source to destination.
• Bandwidth indicates a medium's data-carrying capacity.

Media Types

• Metal wires use electrical impulses. Examples:
  • Ethernet cables (Cat5e, Cat6, Cat7).
  • Coaxial cables.
  • Telephone cables.
• Glass or plastic fiber use light pulses for longer range connections. Example:
  • Fiber-optic cables.

Network Diagrams

• Network diagrams (topologies) use symbols to represent devices.
• Important terms:
  • Network Interface Card (NIC): connects the end device to the network.
  • Physical port: where the media connects on a networking device.
  • Interface: specialized ports for media connection.

Physical and Logical Topologies

• Physical topology illustrates physical locations, used for troubleshooting.
• Logical topology shows logical grouping of related devices via IP addresses. Useful for connecting devices

Common Network Types

• Simple home networks share resources like printers, documents, and media.
• Small home networks connect computers to each other and the Internet.
• Small Office/Home Office (SOHO) networks connect remote offices to a corporate network.
• Medium to Large Networks: connect many locations with numerous interconnected computers.
• World Wide Networks: connects millions of computers, Ex. The Internet.

LANs and WANs

• Network infrastructures vary in size, user count, services, and area of responsibility.
• LAN - Local Area Network:
  • Spans small geographical areas.
  • Interconnect end devices in a limited area.
  • Administered by a single entity.
  • Provides high bandwidth.
• WAN - Wide Area Network:
  • Spans wide geographical areas.
  • Interconnects LANs over wide distances.
  • Administered by one or more service providers.
  • Typically provides slower speed links between LANs.

The Internet

• A worldwide collection of interconnected LANs and WANs using copper wires, fiber optic cables, and wireless transmissions.
• Largest network in existence, not owned by any one entity.
• Groups like the IETF and ICANN help maintain structure.

Private Networks

• Intranets are private LANs and WANs accessible only to members of an organization.
• Extranets grant secure network access to individuals from other organizations.
• Examples:
  • Company providing data access to suppliers/contractors.
  • Hospital providing a system for doctor appointments.
  • Local office providing budget and personnel information to schools.

Connection Types

• Cable: high bandwidth, always on internet.
• DSL: high bandwidth, always on over telephone lines.
• Cellular: uses cellular connection.
• Satellite: rural areas, require clear line of sight.
• Dial-up telephone: inexpensive.

Business Internet Connections

• Dedicated Leased Line: connects distant offices with private voice/data networking.
• Ethernet WAN (Metro Ethernet): extends LAN into the WAN.
• Business DSL: symmetric uploads and downloads.
• Satellite: provides solutions when wired connections are unavailable.

Converging Networks

• Before conversion, different lines and technologies were required to carry and transfer signal.
• Converged Data Networks carry multiple services on a single link.

Network Architecture

• Underlies data transfer by needing to address user expectations for:
  • Fault Tolerance: provides continued operation despite component failures.
  • Scalability: supports growth.
  • Quality of Service: prioritizes traffic.
  • Security: physically secures devices and prevents unauthorized access.

Fault Tolerance

• Limits impact of failure, needs multiple paths.
• Packet switching splits traffic into packets, with each packet taking different paths.

Scalable Network

• A scalable network easily expands to support more users and applications.

Quality of Service

• Voice and video transmissions often need higher quality of service.
• The primary mechanism to ensure content delivery.

Network Security

• Two main types:
  • Network Infrastructure Security: physical setup that prevents unauthorized access.
  • Information Security: protects transmitted data.
• Three goals:
  • Confidentiality: keeps data viewable only by intended recipients.
  • Integrity: prevents data alteration during transmission.
  • Availability: ensures reliable data access for authorized users.

Recent Trends

• Trends impacting organizations/consumers:
  • Bring Your Own Device (BYOD).
  • Online Collaboration.
  • Video Communications.
  • Cloud Computing.

Bring Your Own Device (BYOD)

• BYOD allows users to use their own devices.
• Gives opportunities and more flexibility for users.

Online Collaboration

• Working with others over a network on joint projects.
• Many tools such as Cisco WebEx give users ways to connect.

Video Communication

• Can make video calls anywhere, used for communication.
• Video is critical so there is effective collaboration.

Cloud Computing

• Allows you to store data, backup onto server.
• Accessed by using this Cloud.
• Smaller companies with no data centers, lease server and storage services.

Types of Cloud Computing

• Public Clouds: available through pay basis.
• Private Clouds: Specific to only the government.
• Hybrid Clouds: Made up of two cloud types with the same architecture.
• Custom Clouds: Built to meet specific needs of industry such as health and media.

Technology Trends in the Home

• Smart home technology: Integrates appliances for interconnectivity throughout the house.
• Powerline Networking Enables devices to connect to LANs, using connections where network wireless is not available. Useful when there are many users.
• Wireless Broadband: Wireless system used to connect in homes and smaller businesses.

Security Threats

• Network security: integral in all networks, must balance environment and expected QoS. It is through different technologies and securing data threats, and internal actions.
• External Threats:
  • Viruses, worms, trojan horses: malicious software.
  • Spyware and adware: Collects information.
  • Zero-day attacks: Vulnerability occurs when first discovered.
  • Threat actor attacks: malicious attacks.

Computer Basics

• Denial of service attacks: slowdowns or crash's data.
• Data inception and theft: captures personal data.
• Identity theft: accesses private data.
• Losing or stealing devices.

Security

• Important with multple layers.
• Network security like firewalls need to protect from software, and unauthorized access.

CCNA

• Ensure with next gen technologies
• New foundation of IP and security
• Wireless, virtulization of a network

IOS-Shell

• Allows use to request specific tasks from the computer like the GUI or CLI

Kernel

• Communicates how resources are being used to meet requirements

###Hardware

• Physical parts that help with understanding electronic

###Access Methods

• Console :Physical management, helps with connections and maintenence
• Secure Shell (SSH): Establishes secure remote connection

###TELNET

• Insecure remote CLI connection

###User EXC Modes

• Allows access to only limited numbers of the commands

###Privileged Exec code

• Allows access to codes, which identified by hash symbol
• Use for access features

###Global Configurations

• Need to use configurations options
• identified when configs are shown

###Types of codes

• Sub configuration mods, line configurations, and interface configurations

###IOS Modes

• Use"the configure terminal" command, followed with a line and exit commands. Allows to change the device names.

###Commands

• IOS commands check, with multiple arguments and syntaxes, and can be shortened. Ex the configure code.

###Hot Keys

• IOS helps make configuring more easier
• Device Names.

###Switch

• First is set to a certain host name
• Uses the enable code

Securing

• Use the secure codes to access lines VTU and VTI, to allow connection codes.

###Encrypts

• Encrypts all codes with"service password encryption global config command"

###Banner messages Note that are used to warm about what is about to happen

###Router show start up confit

• Uses to erase start-up configurations commands

Captureing

• Captures the configuration to a text file (helps if any code is wrong)

###Ethernet When IP is being transferred. (Means for connecting devices)

###IP Adress

• A system for use to tell any devices and enable systems, It's called a dotted decmial which is a system made up of 4 decimals.
• Default Gateway address: IP for the router

###Configure End devices

• Have to manually configure device, to know what the device is
• Click properties and IPv4

###End Network

• Device need a IP to communicate

###End LAN.

• Use what the DHCP allows

###Virtual interface config

• Use the configurations for the virtual switch

###SVI on a switch

• Enter the interface vlan code- the interface uses 1 command mode.
• Has the IP adress-uses a sub code

Summery

• All devices have an operating system
• Basic device configurations: Hosts, passcode
• All device has needs IPl-helps get each communication

###Packet Tracer tools

• Use 3 menus to make things easier
• Add Device
• Select device, to inspect it

Network Managment

• Open exiting network
• Save current user for files
• Helps modify the user setting

###Files types

• PKA. Packet tracer activity: can be used to score and contain codes
• PKT File Types: saved in Packet, not instructions
• PK2 files: used to help embed images •Use PkSZ when needing files

###Packer tracer

• Show model and questions, to help access information.

###CLI tab

• Access command line
• Code enters will show on CLI Tab

###Services Tab

• All hosts have to help get info, has add ons with additional codes

###TCP\IP

###Physical\ Config Tab

• Graphic tab that has functions for the internet

###Protocols •The best rules that will follow

• Individuals must use established rules for conversations. Ex: code style

###Protocols account

• Identification and grammar, grammar and construction, and timing

###Requirements

• Message can be sent and delivers quickly because device can read and response

###Message delivery

• One and One Communication and One to Many
• One the all is not any for the 1Piv6 but with other options Networking will have different rules

###Networks Protocols over code.

###Protocol function •Address code, data rate, and date labels

###Protocols Types.

• Networks Communucations
• Networking Security
• Rotuing
• Services Discory

###TCP •Devices and processes to show them where and how to send traffic •This helps with the data and transfer in many ways

###Data link. Creates links to the network. It then can be broken up into little things

###Transport

• This has a list and helps keep each segment of data going in an orderly path.

Protocols

###Application

• Contains information
  ###Network.

Protocols

OSI

• Used to support communication and how they link with data

###TCP\IP

• Allows for network acess and application code

OSI\TCP

•Important

Encapsulation

• Data is being sent then it goes through a certain process

De encapsulation

###A bit Stream, helps read the stack.

Addresses

• Aide data deliver souce to destination at all.

Data Link\ Layers

• Help distribute data to devices with a specific address There is data deliver to the Ethernet

###Layer Codes •Different

###Data access •Network Data link layer are going to provides data

Chapter 4

• Physical layers

###Data Links

•The link can be Ethernet and transfer between local media to different things

###Properties.

"Metal

###Physical Components "Metal #Encoding #Signaling

Encoding

• Converts stream of bits, helps with data Ex(10 MB Ethernet)

Cable

• Data transports through cable\wireless -Accept Data and make them read it into signal
• This is last set in Encaptilation Code, tells the device where and what to do (helps it take control)

###Types

• ISO -EIA\TIA -ITU-T -ANSI -1EEE
• Electrical -Cable. Data travel weaker because of resistance.