VLAN Management Quiz

Network Topologies

• Network topology refers to the arrangement and connection layout of computers and network components, encompassing both physical and logical layouts.
• Physical topology deals with the actual setup of cables and devices, while logical topology describes how the network appears to its users.

Types of Wired Topologies

• Bus Topology

  • Utilizes a central backbone cable; all nodes connect to this single cable.
  • Each device taps into the cable to receive data packets.
  • Requires terminators at both ends to prevent signal reflection.
  • An older technology, rarely used in modern networks.

• Ring Topology

  • Each computer connects in a circular formation, passing packets sequentially.
  • A single failure (computer or cable) disrupts the entire network.
  • No hub or switch is needed; impractical in frequently changing environments.

• Star Topology

  • All devices connect to a central hub or switch, facilitating easy management and expansion.
  • Each device uses a separate cable to connect, minimizing the impact of individual cable failures.

• Mesh Topology

  • Every device connects directly to every other device, enhancing redundancy.
  • Complicated wiring and high cabling costs limit practical use in small networks; more common in metropolitan or wide area networks.

Types of Wireless Topologies

• Wireless topologies mirror wired topologies but utilize wireless communication technologies, often integrating components like routers and access points.

Types of Networks Based on Geographic Area

• LAN (Local Area Network)

  • Restricted to a small geographical area (e.g., single building or campus).

• WLAN (Wireless Local Area Network)

  • A LAN that employs wireless communication instead of physical cables.

• WAN (Wide Area Network)

  • Covers multiple locations, connecting several LANs; generally slower and more complex than LANs due to required hardware.

• MAN (Metropolitan Area Network)

  • Smaller than WANs, covering areas like cities or towns; often provided by ISPs.

• CAN (Campus Area Network)

  • Links multiple LANs across a defined geographical area, such as a college campus or business campus.

• SAN (Storage Area Network)

  • A specialized network for connecting shared storage devices, offering block-level data storage.

• PAN (Personal Area Network)

  • Personal networks for close-range device communication (e.g., smartphones and laptops), often utilizing Bluetooth or NFC technologies.

Network Devices

• Router

  • Connects different networks, routing data between them (e.g., home office routers connecting to the Internet).

• Switch

  • Interconnects multiple devices within a network, sending data only to the correct destination device based on MAC addresses.

Routing and Switching Methods

• Routing

  • The process of directing data packets across networks; performed by routers to ensure packets reach their correct destinations.

• Virtual Circuits

  • A connection-oriented service providing a dedicated communication path, adding complexity compared to connectionless packet switching, which is more adaptable and scalable.

Network Topologies Overview

• Network topology defines the arrangement of devices in a network, comprising both physical and logical layouts.
• Physical topology refers to the real-world layout of cables and devices, while logical topology illustrates how the network appears to users.

Wired Network Topologies

Bus Topology

• Connects all computers in a linear fashion via a single backbone cable.
• Each node taps into the cable to access data packets.
• Requires terminators at both ends of the cable to prevent signal reflection.
• Considered outdated and not widely used today.

Ring Topology

• Each computer is connected in a closed loop, with data packets traveling in one direction.
• Each node examines packets to determine if they are intended for it.
• A failure in any node or connection disrupts the entire network.
• Rarely used due to issues with network changes and reliability.

Star Topology

• All devices connect to a central hub or switch, forming a star shape.
• Each device has a dedicated cable to the hub, allowing for easy network expansion.
• If one cable fails, it does not affect the rest of the network.
• One of the most popular topologies for both home and office networks.

Mesh Topology

• Devices connect to every other device, offering multiple pathways for data.
• Provides high redundancy; single cable failures can still allow communication through alternate paths.
• Complicated wiring and high costs make it less common in LAN settings but useful in metropolitan or wide area networks.

Wireless Network Topologies

Infrastructure Wireless Topology

• Devices communicate through a central access point such as a wireless router.
• Common in home and office networks for internet connectivity.

Ad Hoc Wireless Topology

• Allows devices to connect directly with one another without a central access point.
• Often used in temporary or mobile settings, like peer-to-peer connections.

Wireless Mesh Topology

• Every device connects to all others, ensuring reliability through rerouting of data if one node fails.
• Ideal for highly available networks but more complex than traditional setups.

Hybrid Topology

• Combines multiple types of wireless topologies to create a flexible and adaptable network.

Geographic-Based Networks

Personal Area Network (PAN)

• A small network focused on personal devices (e.g., smartphones, tablets).
• Incorporates wireless technologies, forming Wireless Personal Area Networks (WPAN).
• Commonly uses Bluetooth or NFC for data exchange.

Network Devices

Router

• Interconnects networks, routing data between them.
• An example includes a small office/home office router connecting to the Internet.

Switch

• Connects multiple computers in a network using cable connections.
• Efficiently forwards data only to the port connected to the destination device, based on MAC addresses.

Routing and Switching

Routing

• The process of directing data packets across networks to ensure they reach their destinations.
• Utilizes routers to make routing decisions.

Virtual Circuits

• A communication method in packet-switched networks providing a connection-oriented service.
• Offers a predictable path for data, but adds complexity and overhead compared to connectionless methods.
• Choice of method depends on application requirements and network characteristics.

Purpose of WANs

• WANs connect LANs over larger geographic distances, interlinking enterprises with remote locations and branch offices.
• Service providers own WANs, unlike LANs, which are typically organization-owned. Fees are incurred for WAN services.
• WANs facilitate communication for remote sites, enabling data, voice, and video transport.

Necessity of WANs

• Without WANs, LANs remain isolated, hindering communication between distant sites.
• Businesses require inter-office communication for sharing data, especially for regional and branch offices.
• Increased connectivity needs arise from mobile employees and consumer interactions with online services.

WAN Topologies

• Various topologies are utilized to interconnect sites via WANs. Key examples include:
  • Point-to-Point: Direct, dedicated connections like T1/E1 lines between two endpoints.
  • Hub-and-Spoke: Central hub connects multiple spoke sites, facilitating shared access.
  • Full Mesh: Allows direct communication between all sites but requires more virtual circuits.
  • Dual-homed: Offers redundancy and load balancing, though more expensive and complex to set up.

Evolving Networks

• Companies focus on optimizing network efficiency to boost profitability during economic downturns.
• Networks must adapt as companies expand, illustrated by SPAN Engineering’s growth from local to global scale.

Small Office Setup

• SPAN Engineering has 15 employees, utilizing a single LAN for VoIP, peripheral sharing, and internet access via DSL.

Campus Network Expansion

• After five years, SPAN expands infrastructure, transitioning to several subnetworks within a multi-floor office building.

Branch Networking

• As SPAN opens branch offices, a WAN is implemented to enable remote access to the central data center.
• Local branches use dedicated lines, while international branches rely on the Internet for connectivity.

Distributed Network Maturity

• SPAN Engineering reaches a global presence with thousands of employees, requiring sophisticated network services for efficiency and cost reduction.

WAN Operations and OSI Model

• WANs operate mainly at the OSI Model's Physical and Data Link layers, focusing on physical addressing and flow control.
• Various authorities set standards for WAN access including TIA/EIA, ISO, and IEEE.

Common WAN Terminology

• Customer Premises Equipment (CPE): Devices at the enterprise edge that connect to a carrier.
• Data Communications Equipment (DCE): Interfaces connecting customers to the WAN.
• Data Terminal Equipment (DTE): Devices sending data for WAN transmission.
• Demarcation Point: Divides customer and service provider equipment.
• Local Loop: Connects CPE to Central Office (CO).
• Central Office (CO): Service provider facility connecting to the network.

WAN Devices

• Dialup modem: Converts digital signals for public telephone networks.
• Access server: Manages dial-up communications.
• Broadband modem: Used with high-speed Internet connections, operating at higher frequencies.
• CSU/DSU: Ensures digital signal integrity and compatibility with LAN frames.
• Router: Connects networks and allows WAN access.
• Core router/Multilayer switch: Operates within the WAN backbone.

Circuit Switching

• Establishes dedicated channels between nodes before communication begins.
• Examples include PSTN and ISDN, with communication requiring completed connections prior to data exchange.

Packet Switching

• Splits data into packets routed over shared networks without pre-established circuits.
• Connectionless systems (e.g., Internet) carry full addressing in each packet, while connection-oriented systems (e.g., Frame Relay) utilize route identifiers.
• Packet switching tends to be cheaper than circuit switching but faces higher latency and jitter.