Network Architecture and System Reliability

In ring topology, all hosts are connected in a circular arrangement where each node connects to exactly two neighbors. Data flows around the ring through the common path. Cellular uses cells, star has a central node, and mesh connects everything directly.

Cellular topology arranges nodes in hexagonal geographical areas called cells, with each cell having a node at its center. This is how mobile networks organize coverage. Ring, star, and mesh don't use geographic cells.

Star topology has a central hub or switch through which all communication passes. Each node connects only to the central node, not to each other. This centralizes control and simplifies management.

Tree topology organizes nodes in a hierarchical structure with root nodes, branches, and leaves. Information flows up and down this hierarchy, making it suitable for organized, structured networks.

This backup scheme uses 5 daily tapes (Monday-Friday) and 4 weekly tapes, which is a monthly rotation scheme. Grandfather-Father-Son uses daily, weekly, and monthly tapes. Tower of Hanoi uses a different mathematical pattern.

Hot swap refers to components that can be added or removed while the system remains powered. Cold swap requires system shutdown, and warm swap is not a standard term. Hot spare is a standby component, not the removal process.

A hot spare is a backup component that is powered on, configured, and ready to take over immediately if the primary component fails. This differs from swap types which describe how components are replaced, and from cold/warm spares which require startup time. Hot spares provide the fastest failover time.

Clustering allows multiple servers to work together so that if one fails, others can immediately take over, providing high availability to users. RAID protects against drive failure but not server failure. Backup sites are for disaster recovery, not continuous availability. Extra memory doesn't provide HA.

Incremental backup copies only files with their archive bit set (indicating they've changed since the last backup), then resets the bit to mark them as backed up. This is efficient because only changed files are copied. Differential backup keeps the archive bit on, copying all changes since the last FULL backup.

A hot site is a fully equipped facility with hardware, software, and personnel ready to immediately restore critical business operations. Cold sites have space/power but no equipment. Warm sites have some hardware but may lack current data. Backup sites are general terms, not specific facility types.

Scalability refers to a system's ability to handle increased load by adding capacity, which is what additional capacity addresses. Availability means staying operational. Reliability means consistent operation. Redundancy means having backup components. Scalability specifically accommodates growth.

In RAID systems, hard drives are redundant by design - multiple drives store the same data or parity information so that if one drive fails, data isn't lost and the system continues operating. Fans, NICs, and processors can be redundant in other contexts but RAID specifically protects against drive failure.

DNS servers publicly map domain names to IP addresses, revealing a network's structure and host information. Hackers can query DNS to discover subdomains, mail servers, and other hosts, providing reconnaissance for attacks. TCP/IP is a protocol, not a server. Telnet and SSL don't expose network topology like DNS does.

Server clustering ensures high availability by allowing multiple servers to back each other up - if one fails, others immediately take over with minimal downtime. Hot swap drives protect against disk failure but not server failure. Multiprocessors and scalable storage improve performance but don't guarantee availability.

IP spoofing involves an attacker sending packets with forged source IP addresses to make them appear to come from a trusted source, bypassing authentication or hiding the attacker's identity. It's a network-layer attack. Options A and C describe social engineering. Option D describes phishing.

RAID 5 provides fault tolerance through distributed parity and excellent read performance through striping across multiple disks, making it ideal for read-intensive applications. RAID 0 has no fault tolerance. RAID 1 mirrors but has lower performance. RAID 3 has dedicated parity creating a bottleneck. RAID 5 balances performance, cost, and redundancy.

Cellular topology broadcasts data over radio waves, making it inherently vulnerable to interception, eavesdropping, and unauthorized access since the medium is shared and publicly accessible. Linear bus, star, and ring topologies typically use wired connections which are physically more secure and harder to intercept without direct access.

Mesh topology provides multiple redundant paths between nodes, so if any link or node fails, traffic can route through alternative paths, making it ideal for uninterrupted communications. Ring topology has single points of failure between nodes. Star topology depends on the central switch. Hierarchical topology has single points of failure at each level.

A switch operates like a multiport bridge because it learns MAC addresses and forwards frames only to the specific port where the destination device is connected, unlike a hub which broadcasts to all ports. Switches operate at Layer 2 and provide dedicated bandwidth to each port.

A switch provides concentrated connectivity by connecting multiple devices while making transmission efficient through MAC address learning and selective forwarding. Unlike hubs that broadcast to all ports, switches send data only to the destination port, reducing collisions and improving performance.