Difference between Physical and Logical Topology

A Physical and Logical topologies are important concepts that govern the formation and operation of networks. In this article we will see differences between both topologies, and troubleshooting network infrastructure.

What is Physical Topology?

Physical topology indicates the arrangement of different elements of a network. It reflects the physical layout of devices and cables to form a connected network. It is concerned with the essentials of the network ignoring minute details like transfer of data and device type. The pattern of arrangement of nodes (computers) and network cables depends on the ease of installation and setup of the network. It affects cost and bandwidth capacity based on a solution of devices. It takes into account the placement of nodes and the distance between them. Devices can be arranged to form a ring (Ring Topology) or linearly connected in a line called Bus Topology.

Types of Physical Topology

The arrangement of a network that comprises nodes and connecting lines via sender and receiver is referred to as Network Topology. On the basis of arrangements, Physical Topology has several types:

1. Mesh Topology
2. Star Topology
3. Bus Topology
4. Ring Topology
5. Hybrid Topology

Advantages of Physical Topology

• Reliability: Some physical topologies, including the mesh topology, provide redundancy, making sure that community connectivity is maintained although a connection or device fails.
• Tangible Representation: Physical topology offers a concrete representation of how devices are physically linked, aiding in troubleshooting and maintainence responsibilities.
• Scalability: Certain physical topologies, like the star topology, provide scalability, allowing for smooth expansion by means of including extra devices.

Disadvantages of Physical Topology

• Vulnerability to Physical Damage:Physical topologies are liable to disruptions resulting from physical damage to cables or networking hardware.
• Limited Flexibility: Changing a network's physical architecture can be difficult and involve a significant amount of reconfiguration.
• Costly Implementation: Some physical topologies can be quite expensive to build, especially if they include a lot of cables or redundant hardware.

What is Logical Topology?

Logical Topology reflects the arrangement of devices and their communication. It is the transmission of data over physical topology. It is independent of physical topology, irrespective of the arrangements of nodes. It is concerned with intricate details of network like type of devices (switches, routers) chosen and their quality, which affects rate and speed of data packets delivery. The logical topology ensures optimal flow control that can be regulated within network. The data can either flow in a linear pattern called Logical bus or in form of a circle Logical ring.

Types of Logical Topology

Logical topology refers to the manner in which the data is transported and the network device structure is displayed. On the basis of data transfer, logical topology have below mentioned types:

1. Ethernet
2. TCP/IP
3. OSI

Advantages of Logical Topology

• Flexibility: Logical topology allows community engineers to design and configure networks based totally on logical necessities, without being constrained by using physical limitations.
• Efficient Resource Utilization: Using logical topology to define efficient information paths and routing configurations, the most efficient use of resources is made possible.
• Ease of Implementation: Making changes or improvements to a logical topology is frequently less difficult and disruptive than making changes to a community's physical layout.

Disadvantages of Logical Topology

• Complexity: Technical expertise and understanding may also be needed to comprehend and manage the complexities of logical topology, which includes protocols and routing configurations.
• Dependency on Protocols: Logical topology is contingent upon the proper functioning of network protocols, making networks prone to issues arising from protocol failures or misconfigurations.
• Potential Security Risks: Misconfigurations or vulnerabilities in logical topology components, which include routing protocols, may leads to security risk

Difference between Physical and Logical Topology

Question for Practice

If there are 'N' devices (nodes) in a network, what is the number of cable links required for a fully connected mesh and a star topology respectively. [ ISRO CSE 2017]

(A) N(N-1)/2 , N-1

(B) N , N-1

(C) N-1 , N

(D) N-1 , N(N-1)/2

Solution: Every node in a fully connected mesh topology should be connected to every other node, thus there will be = N (N − 1) / 2 links. while in star topology every device is connected with the central hub, so N-1 links. Hence option (A) is correct.