Network Topologies and TCP/IP Architecture
Chapter 2: Network Topologies
Star Topology
All nodes connect to a central node, with messages passing through it.
Loop Topology
Nodes connect in a ring, with one node controlling and determining channel access for other nodes.
Mesh Topology
Nodes interconnect in a complex configuration, sharing communication circuits when transmitting. The most commonly used topologies are ring and bus.
Ring Topology
Each node connects to two others. Each node has a repeater with logic circuitry to transmit and manage data. Messages circulate until removed or marked as available. The sending node usually removes the message.
Advantages
- Equal transmission capacity sharing.
- No reliance on a central device.
- Easy error location.
- Simplified message distribution.
- Easy error checking.
- Guaranteed access, even during overload.
- Potential for high transmission speeds.
Disadvantages
- Reliability depends on repeaters and ring integrity.
- A monitoring device is often needed.
- Difficult expansion.
- Adding nodes disrupts the ring.
- Slow repetitive signals.
- Complex installation and cable layout.
Bus Topology
Devices attach to a shared communication medium. A transmitting node sends information to the channel, receivable by all nodes.
Baseband
Digital information transmits as pulses. Only one node transmits at a time to avoid collisions. Time multiplexing is used.
Advantages
- Passive transmission medium.
- Easy device connection.
- Good device access.
- Easy installation.
- A single interface can connect multiple low-speed devices.
Disadvantages
- Vulnerable to eavesdropping and disruption.
- Interfaces require processing capabilities.
- Unequal resource sharing.
- Limited channel length (1-2 km).
Broadband
Multiplexing is frequently used, often with coaxial cable. This technology is common in cable television. Active components like modulators, demodulators, and repeaters are required.
Advantages
- Readily available transmission medium and interfaces.
- Covers large distances.
- Easy expansion with new branches and devices.
TCP/IP
Its goal is resource sharing through a communication network.
Characteristics of TCP/IP
- Uses packet switching.
- Provides reliable connections.
- Interconnects diverse networks.
- Relies on lower-level protocols (e.g., Ethernet, Token-Ring).
- Uses full-duplex, point-to-point connections.
Network Interconnection Architecture of TCP/IP
Goals
- Technology independence.
- Universal connectivity.
- End-to-end delivery.
- Standardized protocols.
Features
- Connectionless network-level protocols.
- Packet switching.
- Secure transport protocols.
- Common application programs.
Network Interconnection
- Gateways connect networks.
- All networks are treated as equals.