Computer Networks

In Rogers Telecommunications, customer calls are forwarded to agents through a system infrastructure consisting of PBX (Private Branch Exchange), LAN (Local Area Network), and Host Computer. The PBX handles call routing, the LAN connects the system components, and the host computer manages the call data and agent interactions. SPI, OmniVox3D Application layer, and CTI (Computer Telephony Integration) are related technologies but not the complete forwarding path.

Infrastructure applications are foundational software systems that support core IT operations. A VPN provides secure network communication infrastructure, network management systems monitor and control infrastructure, email is fundamental communication infrastructure, and office productivity software (while end-user facing) is part of the standard software infrastructure in organizations. All these represent different layers of IT infrastructure.

Microsoft systems typically use CIFS (Common Internet File System) to connect to NAS for file sharing. NFS (Network File System) is typically used by Unix/Linux systems. BDMP and DART are not standard file sharing protocols.

The Fibre Channel switch provides physical connections and logical routing between devices in a SAN fabric. Fibre cable is just the physical medium. HBA (Host Bus Adapter) connects servers to the fabric. Storage array contains the actual storage devices. The switch is the intelligent component that routes traffic.

FC arbitrated loop (FC-AL) is the topology that uses hubs to connect devices in a loop, with arbitrated access to the loop. Switched fabric uses switches, not hubs. Mesh topologies (full or partial) require point-to-point connections between devices, not hub-based architecture. The hub is the defining characteristic of arbitrated loop topology.

NAS (Network Attached Storage) provides file-level storage consolidation for multiple servers, while SAN (Storage Area Network) provides block-level storage consolidation. Option A correctly identifies this distinction. Options B, C, and D are reversed: SAN uses block-level protocols (FC, iSCSI), NAS uses file-level protocols (NFS, SMB), NAS uses TCP/IP, SAN uses FC, and both support multipathing capabilities.

This question asks which statement is FALSE (all true except). FC-SW (switched fabric) is analogous to Ethernet switching, not token ring. Options A, B, and C are all true: WWNs are like MAC addresses (unique device IDs), FC port IDs are like IP addresses (assigned addresses for communication), and private FC-AL uses 8-bit addressing (limiting to 126 devices after addressing overhead). The question structure correctly identifies D as the false statement.

The Host Bus Adapter (HBA) is the hardware component that physically and logically connects a host computer's I/O bus (such as PCI) to a Fibre Channel network. It acts as the interface card installed in the server, converting protocol and electrical signals between the host system and the SAN fabric. Fibre cables simply transmit data, switches route traffic, and storage arrays store data - only the HBA provides the actual connection point from the host to the network.

Single-mode fiber for ISLs (Inter-Switch Links) in Fibre Channel networks can support distances up to approximately 20 kilometers. Single-mode fiber uses a single light path and laser light sources, allowing for longer distances with less signal attenuation compared to multi-mode fiber. The 20 km distance is a standard specification for long-wave laser transceivers in SAN environments.

Multi-mode fiber for ISLs (Inter-Switch Links) in Fibre Channel networks typically supports distances up to 500 meters. Multi-mode fiber uses multiple light paths and LED or laser sources, which causes modal dispersion that limits effective distance. For longer ISL distances, single-mode fiber must be used instead. The 500 meter distance is the standard limit for multi-mode in SAN environments.

A LAN covers a small geographic area like a single building or campus. WAN spans large distances, MAN covers a city-sized area, and WLAN is wireless LAN. The single-building scope defines a LAN.

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.

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.

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.