Network Management Concepts

Hard Disk Capacity

• The hard disk capacity should be large enough to avoid the need for upgrades in the near future.

Network Resilience

• To mitigate hardware failures, install an uninterruptible power supply (UPS) or run two disks in parallel using disk mirroring or Redundant Array of Inexpensive Disks (RAID) techniques.

Network Clustering

• Clustering involves linking servers together via high-speed connections (e.g., fiber-optic cabling) to distribute workload and enhance reliability and performance.
• This approach enables parallel processing, where tasks are shared between processors, and storage mirroring to improve performance and minimize the risk of server failure.

Client Computers

• Client computers are access points for users and are commonly referred to as clients, nodes, workstations, or PCs.
• Utilize the term "client PC" to distinguish client devices from server PCs.
• Each client requires networking software like Open Enterprise Server (OES) or TCP/IP for network operations.
• Client PCs on a LAN connect to the network via a network interface card (NIC) installed in a slot.
• Home PCs connected to the internet utilize a modem instead of a NIC.

Network Operating Systems

• Applications interact with disk drives on the network through a Network Operating System (NOS).
• The NOS functions as system software that controls network systems and devices, enabling communication.
• Similar to a computer's operating system, the NOS manages memory, tasks, and coordinates hardware.

Network Topologies

• Network topologies describe the physical layout of computer connections and the devices used.
• The four primary topologies are bus, ring, star, and mesh.

Bus Topology

• In a bus topology, computers are connected to a shared communication cable (the bus).
• Data travels bidirectionally along the bus.
• A malfunction on one station can disrupt the entire network.
• Maintaining a logical ring in larger networks is challenging.
• Network adjustments or reconfigurations require temporarily shutting down the entire network.

Ring Topology

• In a ring topology, computers are connected in a circular fashion.
• Data packets flow in one direction.
• A malfunction on one station can disrupt the entire network.
• Maintaining a logical ring in larger networks is challenging.
• Network adjustments or reconfigurations require temporarily shutting down the entire network.

Star Topology

• A star topology connects all computers to a central hub.
• Data transmission flows directly to the hub and is then forwarded to the destination.
• Computers can attempt to send data at any time, but only one transmission can occur simultaneously.
• If two stations transmit data at the same time, neither transmission is successful, requiring the computers to retry after a random delay.

Advantages of Star Topology

• Malfunctions on one station do not disable the entire network.
• It is easier to locate cable breaks and other malfunctions.
• The centralized hub simplifies adding new computers or reconfiguring the network.

Disadvantages of Star Topology

• Requires more cabling than other topologies due to separate lines for each computer.
• The central hub is a single point of failure, and its malfunction shuts down the entire network.

Mesh Topology

• In a mesh topology, each computer is connected to every other computer on the network.
• Requires significant amounts of cabling, increasing cost and installation complexity.
• The main advantage is fault tolerance.
• A network with a broken segment allows data to travel through alternate paths.

Network Types

• Networks are classified based on geographic scope.

Local Area Network (LAN)

• LANs cover a small area like a classroom, school, or single building.
• Costs are lower compared to other network types.
• LANs are typically used for local communications and have high speed components.

Metropolitan Area Network (MAN)

• MANs span a city-wide distance.
• While speeds are typically comparable to LANs, they require high-speed connections like fiber optics.
• The extended distance and advanced technology increase installation and operations costs.

Wide Area Network (WAN)

• WANs networks cover a larger area extending beyond a metropolitan city.
• They utilize long-distance telecommunications for connections, increasing costs.
• The Internet is a large example of a WAN.