2101 Ch01-06 Final Part 1

Networking Technologies

• Networking technologies are significantly changing the world, making national borders, distances, and physical limitations less relevant.
• The internet fundamentally altered social, commercial, political, and personal interactions, fostering global communities.
• Online communities enable global productivity through idea and information exchange.
• Cloud computing allows anywhere, anytime access to documents and applications from any device.

Network Components

• Hosts (End Devices): Devices directly communicating on the network; assigned an IP address for identification.
• Clients: Hosts that request information.
• Servers: Provide information (e.g., email, web pages) to other devices on the network. Each service requires dedicated software. Servers can simultaneously serve multiple clients.
• Client Software: Examples include web browsers (Chrome, Firefox). A single device can run multiple client applications concurrently.
• Peer-to-Peer Networks: Small networks where devices act as both clients and servers.
  • Advantages: Easy setup, decreased complexity, lower cost. Suits simple tasks like file transfer and printer sharing.
  • Disadvantages: Lack of centralized administration, reduced security, not scalable, potential performance issues.
• Intermediary Devices: Connect end devices to the network, facilitating data flow and connectivity.
  • Functions: Regenerate and retransmit signals, maintain routing information, handle errors, direct data, prioritize messages, and enforce security.
  • Examples: Switches, routers. A repeater is a basic function performed by many intermediary devices.

Network Media

• Types of Media:
  • Metal wires (electrical impulses)
  • Fiber-optic cables (light pulses)
  • Wireless transmission (electromagnetic waves)
• Choosing Network Media: Factors: Maximum signal distance, installation environment, data amount/speed, and cost.

Network Topologies

• Topology Diagrams: Visual representations of network connections (physical and logical).
• Physical Topology: Shows physical layout of devices and cable installation.
• Logical Topology: Illustrates devices/ports/addressing schemes.

Network Types

• Local Area Networks (LANs): Connect devices within a limited area (home, office, campus). Managed by a single entity. High-speed bandwidth for internal devices.
• Wide Area Networks (WANs): Span vast geographical distances, often managed by multiple service providers. Connect LANs. Typically slower than LANs.
• Internet: The largest network; a network of networks (internetwork). Connects LANs and WANs.

Internet Connectivity

• Internet Service Providers (ISPs): Provide home users and small offices internet access. Numerous connection options exist (cable, DSL, wireless WANs, mobile).
• Business Connections: Greater bandwidth, dedicated connections, and managed services are business requirements (business-class DSL, leased lines, Metro Ethernet).
• Different Connection Types: Cable, DSL, Cellular, Satellite, Dial-up—each offers different features and performance

Traditional vs. Converged Networks

• Traditional: Separate data, phone, and video networks; distinct technologies and standards.
• Converged: Data, voice, and video delivered over a single network infrastructure. Uses the same standards for communication.

Network Reliability

• Fault Tolerance: Limits affected devices during failures. Employs redundant paths for quick recovery.
• Scalability: Expanding network capacity to handle increasing users/applications without performance degradation.
• Quality of Service (QoS): Manages bandwidth, prioritizes time-sensitive traffic. Prevents congestion in complex internet usage scenarios.
• Security: Protecting network infrastructure and network information. This includes physical security and data protection.

Network Security

• Threats: External (viruses, worms, spyware, zero-day attacks, denial-of-service attacks, data interception/theft, identity theft); internal (lost/stolen devices, accidental misuse, malicious users).
• Security Components: Antivirus/antispyware, firewall filtering (host-based and router-based), dedicated firewall systems, access control lists (ACLs), intrusion prevention systems (IPS), virtual private networks (VPNs).

Network Trends

• BYOD (Bring Your Own Device): Expanding use of personal devices for business/educational networks.
• Online Collaboration: Tools for instant connection and project sharing (e.g., Cisco Webex).
• Video Communications: Increased importance of video for communication and collaboration (videoconferencing).
• Cloud Computing: Storing and accessing data and applications on remote servers (public, private, hybrid, community clouds).
• Smart Home Technology: Integrating smart devices into everyday appliances; automatic and connected home operations.

Home Networking

• Powerline Networking: Using existing electrical wiring to connect devices without cables.
• Wireless Internet Service Providers (WISPs): Provide wireless internet access where traditional services are unavailable.
• Wireless broadband: Cellular-based access for home or small offices, often comparing to DSL and cable services.

Network Devices and Operating Systems

• Operating Systems (OS): Essential for all network devices (including home routers).
• Kernel: OS portion interacting directly with hardware.
• Shell: OS portion interacting with applications and users (CLI or GUI).
• Cisco IOS (Internetwork Operating System): A family of network OSs, commonly used on Cisco routers and switches. Differs by device type.
• SSH (Secure Shell): Secure remote access protocol - encrypts communication.

Network Operating System Configuration

• Command Modes: User EXEC (basic monitoring, > prompt), Privileged EXEC (# prompt, configuration changes), Global configuration (config#, overall device config), Line configuration (config-line#, console/Telnet/SSH config), and Interface configuration (config-if#, interface config).

• Password Management:

  • Importance of strong, unique passwords; avoid common words. Passwords should exceed 8 characters.
  • Password strength considerations

• Security Features:

  • Device naming (hostnames)—critical for identification. Naming conventions and documentation.
  • Banners—legal notices displayed when accessing devices.

Configuring and Managing Network Devices

• Configuration Files:
  • startup-config (NVRAM, loaded at boot)
  • running-config (RAM, current config)
• Saving Configurations: Saving running-config to startup-config.
• Restoring Configurations: Reloading the device to return to factory configurations.
• Manual Configuration Restoration: Restoring configurations through saved files.

Network Addresses and Protocols

• IP Addresses: Logical addresses for identifying devices on a network; IPv4, IPv6; dotted decimal (IPv4) or hexadecimal (IPv6) format. Subnet mask, and default gateway information required for an IPv4 address.
• Subnet Masks: Differentiate the network and host portions of an IP address for IPv4, prefixes define network portion of IPv6 addresses.
• Network Interface Cards (NICs): Physical interfaces for connecting the computer to network cables
• Data Link Layer Addresses: Physical addresses for devices on the same network (MAC addresses).
• DHCP (Dynamic Host Configuration Protocol): Automatically assigns IP addresses.
• Switch Virtual Interfaces (SVIs): Virtual interfaces on Layer 2 switches for assigning IP addresses for remote management.
• Network Access Layer: Protocols (Ethernet, Wi-Fi, cellular) that deliver IP packets over physical media.

Network Protocols

• Protocol Suites: Groups of interrelated protocols enabling communication (TCP/IP, OSI).
• TCP (Transmission Control Protocol): Reliable, ordered data delivery.
• UDP (User Datagram Protocol): Faster but less reliable data delivery.
• HTTP (Hypertext Transfer Protocol): Used for web browsing.
• SSL/TLS (Secure Sockets Layer/Transport Layer Security): Secure data transmission.
• SSH (Secure Shell): Secure remote access to network devices.
• OSPF (Open Shortest Path First), BGP (Border Gateway Protocol): Routing protocols for determining packet paths.

Layered Models

• OSI Reference Model: Seven-layer model describing network functions & interactions.
• TCP/IP Reference Model: Four-layer model closely related to the TCP/IP suite.

Segmentation and Encapsulation

• Segmentation: Dividing data into smaller units (packets). Improves speed and efficiency.
• Encapsulation: Adding protocol information to data at each layer.
• Protocol Data Unit (PDU): Data representation at each layer (data, segment, packet, frame, bits).
• De-encapsulation: Removing protocol headers at each layer.

Network Addresses

• Network Layer Addresses (IP Addresses): Identify source and destination for IP packets (IPv4; IPv6). The IP includes a network portion, that specifies the network to which the computer is connected, and a host portion, which identifies the specific computer on that network. Both the source and destination addresses are included in the IP packet.

• Data Link Layer Addresses (MAC Addresses): Physical addresses for devices on the same network (identify devices, not networks).

Test your knowledge on the fundamentals of computer networking with this quiz. Explore key concepts such as IP addresses, LAN characteristics, and the roles of various network components. Perfect for beginners and students of computer science!