PHASE 02

Architectures & Network Topologies

Analyzing physical connection layouts, failure domains, P2P vs Client-Server models, and Domain Network Operating Systems.

1. Physical & Logical Network Topologies

Legacy Topology

Bus Topology

All nodes connect to a single central coaxial cable backbone terminated at both ends with 50-ohm resistors.

Pros: Minimal cabling required, cheap setup
Cons: Single backbone break drops the entire network; high packet collision rates

Modern Enterprise Standard

Star Topology

All end devices connect directly to a central multiport switch or hub using individual dedicated cables.

Pros: High fault tolerance—single cable failure affects only one device; easy to expand
Cons: Central switch is a single point of failure (SPOF)

Token Passing

Ring Topology

Nodes are connected in a closed circular loop. Signals travel in one direction passing a special token frame.

Pros: Deterministic traffic control; no packet collisions
Cons: Unidirectional failure breaks ring unless dual-ring (FDDI) is deployed

Maximum Reliability

Mesh Topology

Every node has a direct point-to-point link to every other node in the network ($Links = \frac{n(n-1)}{2}$).

Pros: Absolute redundancy, privacy, and zero bottlenecking
Cons: Extremely expensive cabling and high port count requirements

2. Peer-to-Peer (P2P) vs. Client-Server Architecture

Peer-to-Peer (P2P) Model

Every node (peer) acts simultaneously as both a client and a server. No dedicated central administrator exists.

Characteristics: Low cost, simple to set up for under 10 devices, decentralized file sharing (e.g. BitTorrent, local home network). Security is decentralized and weak.

Client-Server Architecture

Dedicated server hosts (Domain Controller, Database, Web Server) provide centralized resources and access control to client workstations.

Characteristics: Industrial enterprise standard. Centralized security, single point of policy administration, high scalability, user access privileges governed via Network Operating System (NOS).

3. Network Operating Systems (NOS) & Domain Control

In enterprise corporate attachments (like NUST or corporate offices), computers do not operate in isolation. They are connected to a Domain Server running a Network Operating System (NOS) (e.g., Windows Server Active Directory, Red Hat Enterprise Linux).

🔑 Why Domain Control Matters in Industry

Domain administration centralizes user authentication, privilege policies, group access security, database rights, and automated software deployment across thousands of enterprise workstations from a single administrative console.