2101 Ch01: Networking Today

Network Media Types

• Modern networks interconnect devices using three main media: metal wires (electrical impulses), fiber-optic cables (pulses of light), and wireless transmission (modulated electromagnetic waves).
• Each media type has specific characteristics affecting its suitability for different environments and applications.

Criteria for Choosing Network Media

• Maximum distance capability for signal transmission.
• Environmental conditions for media installation.
• Required data transmission speed and volume.
• Cost considerations for media and installation.

Topology Diagrams

• Topology diagrams visualize device connections within a network, crucial for understanding network configuration.
• Essential for network documentation, comprising physical and logical representations.

Types of Topology Diagrams

• Physical Topology Diagrams: Show the physical layout and device locations.
• Logical Topology Diagrams: Illustrate device interconnections, ports, and addressing schemes.

Extranets Examples

• Companies providing supplier access.
• Hospitals offering booking systems for doctors.
• Educational institutions sharing budget and personnel data with schools.

Internet Connection Methods

• Home users and small offices often access the internet via ISPs using varying connection types:
  • Broadband cable, DSL, wireless WANs, mobile services.
• Business networks require rapid connections for services like IP phones and video conferencing.

Connection Types

• Cable: High bandwidth; runs on cables used for television.
• DSL: Uses telephone lines; ADSL commonly offers faster downloads than uploads.
• Cellular: Connects via cellular networks; limited performance based on network capabilities.
• Satellite: Provides access in remote areas; requires a clear line of sight.
• Dial-up: Inexpensive but low bandwidth; suitable for basic access.

Corporate Connection Options

• Businesses often require higher and dedicated bandwidth options like:
  • Dedicated leased lines for private networking.
  • Metro Ethernet for extended LAN technologies.
  • SDSL for equal upload and download speeds.

Network Evolution

• Traditional separate networks faced limitations in interoperability; new converged networks support multiple services (data, voice, video) on a single infrastructure.
• Converged networks utilize uniform rules and standards.

Data Security Principles

• Confidentiality: Ensures data is accessible only to authorized recipients.
• Integrity: Maintains accuracy of data in transit.
• Availability: Guarantees reliable access to data services for authorized users.

Networking Trends

• Bring Your Own Device (BYOD): Allows personal devices to connect to business networks, fostering flexibility and collaboration.
• Online collaboration: Tools like Cisco WebEx enable instant communication and teamwork among users.
• Video communications: Essential for remote collaboration and engagement.

Wireless Internet Service Provider (WISP)

• Provides wireless internet access, especially in rural areas lacking cable or DSL.
• Subscribers typically attach antennas or dishes to existing structures for network connection.

Wireless Broadband Services

• Competes with traditional DSL and cable by utilizing cellular technology for home and small business internet access.

Network Security Threats

• Security remains a priority due to threats from external sources, including:
  • Viruses, worms, and Trojan horses: Malicious software affecting devices.
  • Spyware and adware: Software that installs on devices without user consent, compromising security.