Introduction To Network Classifications

This blog has the same content as Introduction To Network Topologies, So if you already read that blog so you avoid this.

What Is Topology?

Topology defines the structure of the network of how all the components are interconnected to each other.

There are two types of topology: physical topology and logical topology.

Physical topology is the geometric representation of all the nodes in a network.

Bus Topology

Bus topology is a specific kind of network topology in which all of the various devices in the network are connected to a single cable or line. In general, the term refers to how various devices are set up in a network.

• All of the stations are connected by a single cable known as a backbone cable due to the bus topology’s design.
• A drop cable or a direct connection to the backbone cable connects each node.
• A node puts a message over the network whenever it wants to send a message. Regardless of whether it has been addressed, the message will reach every station in the network.
• Most 802.3 (ethernet) and 802.4 standard networks use the bus topology.
• In comparison to other topologies, the configuration of a bus topology is very straightforward.
• The message is broadcast to all the stations via the backbone cable, which is referred to as a “single lane.”
• Among bus topologies, CSMA (Carrier Sense Multiple Access) is the most popular access technique.

CSMA

It is a media access control that is used to regulate the data flow in order to maintain data integrity, or the prevention of packet loss. There are two alternative ways of handling the problems that occur when two nodes send messages simultaneously.

• CSMA CD(Collision Detection): A collision detection access method, CSMA CD is used to find collisions. The sender will stop sending data once the collision has been identified. It focuses on “recovery after the collision” as a result.
• CSMA CA (Collision Avoidance): It is an access technique used to prevent collisions by determining whether or not the transmission media is in use. If the media is busy, the sender waits until it is free of activity. This method successfully lowers the likelihood of a collision. “Recovery after the collision” is not possible.

Advantages Of Bus Topology

• Low-cost cable: Bus topology connects nodes to the cable directly, bypassing a hub. As a result, the installation has a low initial cost.
• Moderate data speeds: Bus-based networks that support up to 10 Mbps typically use coaxial or twisted pair cables.
• Reliable technology: Bus topology is a well-known technology because hardware components are easily accessible and installation and troubleshooting methods are well-known.
• Limited failure: A node’s failure won’t affect any other nodes.

Disadvantages Of Bus Topology

• Bus topologies are relatively simple, but they still require many cabling.
• Difficult troubleshooting: The cable faults must be found using specialised test equipment. All of the nodes’ communication would be hampered if a cable fault occurred.
• Signal interference: When two nodes send messages at the same time, their signals interfere with one another.
• Difficulty in reconfiguration: Adding new devices to the network would make it slower.
• Attenuation: Communication problems result from attenuation, which is a loss of signal. The signal is renewed using repeaters.

Ring Topology

A ring topology is a network configuration where device connections create a circular data path. Each networked device is connected to two others, like points on a circle. Together, devices in a ring topology are referred to as a ring network.

It creates a ring connecting devices in this topology that have exactly two neighbouring devices.

With a large number of nodes, a ring topology requires a number of repeaters because, in order to send data to the last node in a ring topology with 100 nodes, the data must first travel through 99 nodes. Therefore, repeaters are used in the network to prevent data loss.

Data flow is unidirectional or flows in only one direction, but it can be made bidirectional by having 2 connections between each Network Node; it is called Dual Ring Topology. The workstations transmit data using the Token Ring Passing protocol and an In-Ring Topology.

A ring topology consists of four stations that are connected and each form a ring.

Token passing is the most popular access technique for ring topology.

The following operations take place in ring topology are :

1. One station referred to as a monitor station, is responsible for carrying out all operations.
2. The station must possess the token in order to transmit the data. The token must be made available for use by other stations after the transmission is finished.
3. The token will move around in the ring when there is no station sending data.
4. There are two different methods for releasing tokens: Early token release releases the token immediately after data transmission and Delay token release releases the token after the receiver acknowledges receipt of the data.

Advantages Of Ring Topology

• The data transmission is high-speed.
• The possibility of collision is minimum in this type of topology.
• It is less costly than a star topology.
• Cheap to install and expand.

Disadvantages Of Ring Topology

• Troubleshooting is difficult in this topology.
• The failure of a single node in the network can cause the entire network to fail.
• Less secure.
• The addition of stations in between or removal of stations can disturb the whole topology.

Star Topology

Star topology is a network topology in which each network component is physically connected to a central node such as a router, hub or switch.

In a star topology, the central hub acts like a server and the connecting nodes act like clients. When the central node receives a packet from a connecting node, it can pass the packet on to other nodes in the network. A star topology is also known as a star network.

• A network configuration known as a “star topology” connects each node to a central hub, switch, or computer.
• Coaxial cable or RJ45 cables are used to connect the computers.
• The central computer is known as a server and the peripheral devices attached to the server are known as clients.
• Hubs or Switches are mainly used as connected devices in a physical star topology.
• Star topology is the most popular topology in network implementation.

Advantages Of Star Topology

• Efficient troubleshooting: When compared to the bus topology, troubleshooting in a star topology is much more effective. The manager must examine the kilometres of cable in a bus topology. All of the stations are linked to the central network in a star topology. As a result, the network administrator must visit the single station to investigate the issue.
• Network control: With the star topology, it is simple to implement complex network control features. The star topology is automatically adjusted to any modifications.
• Limited failure: Since each station has its own cable connecting it to the central hub, a cable failure won’t affect the entire network.
• Familiar technology: Star topology is a familiar technology as its tools are cost-effective.
• Cost-effective: Star topology networks are cost-effective as it uses inexpensive coaxial cable.
• Easily expandable: It is easily expandable as new stations can be added to the open ports on the hub.
• High data speeds: It supports a bandwidth of approx 100Mbps. Ethernet 100BaseT is one of the most popular Star topology networks.

Disadvantages Of Star Topology

• A Central point of failure: All of the connected nodes won’t be able to communicate with one another if the central hub or switch fails.
• Cable: Sometimes cable routing becomes difficult when a significant amount of routing is required.

Tree Topology

A tree topology is a special type of structure where many connected elements are arranged like the branches of a tree. For example, tree topologies are frequently used to organize the computers in a corporate network or the information in a database.

In a tree topology, there can be only one connection between any two connected nodes. Because any two nodes can have only one mutual connection, tree topologies create a natural parent and child hierarchy.

This topology is the variation of the Star topology. The data flow in this topology is hierarchical. SAC (Standard Automatic Configuration) protocols like DHCP and SAC are used in tree topology.

In this, the repeater-containing central hub is connected to the various secondary hubs. Both top and bottom directions—from the central hub to the secondary hub and then to the devices—or bottom and top—from the devices to the secondary hub and then to the central hub—are possible for this data flow. It is a multiple-point connection and a non-robust topology since the topology crashes if the backbone fails.

Advantages Of Tree Topology

• It reduces the distance that the signal must travel to reach the devices by enabling more devices to be connected to a single central hub.
• It allows the network to get isolated and also prioritize from different computers.
• Error detection and error correction are very easy in a tree topology.
• We can add the new devices to the existing network.

Disadvantages Of Tree Topology

• If the central hub gets fails the entire system fails.
• If new devices are added, it becomes difficult to reconfigure.
• The cost is high because of the cabling.

Mesh topology

A mesh topology is a network setup where each computer and network device is interconnected with one another. This topology setup allows for most transmissions to be distributed even if one of the connections goes down. It is a topology commonly used for wireless networks.

• Mesh technology is a network configuration in which computers are linked to one another by numerous redundant connections.
• There are multiple paths from one computer to another computer.
• The Internet is an example of mesh topology.
• It has no switch, hub or any other central computer that serves as a hub for communication.
• In WAN implementations where communication failures are a serious concern, mesh topology is primarily used.
• The number of cables = (n*(n-1))/2, where n is the number of nodes that make up the network, can be used to create a mesh topology.

Mesh topology is divided into two categories:

• Full Connected Mesh Topology: Each computer is linked to every other computer in the network in a full mesh topology.
• Partial Connected Mesh Topology: In a partial mesh topology, only a portion of the computers are linked to the computers they frequently communicate with.

Advantages Of Mesh Topology

Reliable: The mesh topology networks are very dependable because a broken link won’t stop connected computers from communicating with one another.

Fast Communication: Communication is very fast between the nodes.

Easier Reconfiguration: The communication between existing devices would not be hampered by the addition of new ones.

Disadvantages Of Mesh Topology

• Cost: A mesh topology has more transmission media than other topologies and a lot more connected devices, like routers.
• Management: Mesh topology networks are enormous and extremely challenging to manage and maintain. The failure of the communication link goes unnoticed if the network is not carefully inspected.
• Efficiency: The number of redundant connections is high in this topology, which lowers the network’s effectiveness.

Hybrid Topology

This topology technology combines all of the various topologies that we have already looked at. It is used when the nodes are free to take any form. This means that they could be singular topologies like the Ring or Star topology, or they could be a combination of the various topologies we saw above. The earlier-discussed protocol is applied to each distinct topology.

Advantages Of Hybrid Topology

• The size of the network can be easily expanded by adding a new device.
• This topology is very flexible.

Disadvantages Of Hybrid Topology

• Hubs used in this topology are very expensive.
• Due to the extensive cabling and network equipment needed for hybrid networks, the infrastructure cost is very high.
• It is very difficult to design the architecture of the Hybrid Network.
• Token: A frame that travels throughout the network.
• Token passing: Using this network access method, a token is passed from one node to another.