Network Topologies

Network Topologies:
Network topologies are the methods to connect different computers in different ways. This section well describes the network topologies.

Types of Topologies:
  •  Physical Topology:
Physical Layout or design of the network is known as the physical topology. We can see and touch the design of the network. 
  • Logical Topology:
Flow of data on the physical topology is referred to as logical topology. It means that in what respect data flows.

1. Star:
A star topology is sometimes referred to as Hub-and-spoke topology. In which centralized device the hub and the other devices are spokes. This topology had huge benefits over the ring and bus topology, that is when any links broke or failed it would not affect the other network but it has disadvantage which is a single point of failure. It means that if the central hub fails it will affect the overall network.


2. Mesh:
In mesh topology we have multiple connections interconnected with one another. If we have offices in different locations then we need WAN. In mesh each office is connected to every other office. 



3. Ring:
In ring topology each node is connected to the next to form a ring. Data is moved in circular form one node to the next node. But the main drawback of ring topology is that if any of the links break down then the whole network will stop working.


4. Bus:
A bus topology contains the single cable that connects all the nodes in a line. The major drawback of this topology is the same as the ring topology, that is if any of the links broke then the entire network will not work.


5. Hybrid:
Any form of networking topology that combines both physical topology and logical topology is known as hybrid topology. There are two forms of hybrid topology one is star-ring topology and the other one is start-bus topology described below with the help of diagram.

6. Star-Ring topology:




7. Star-Bus topology:


Types of WAN Topology:
WAN interconnect geographically dispersed networks like if there are different offices of an organization.
  • Point to Point:
It interconnects two devices. One point of the device to the point of another device. It uses the layer 2 protocols. Most popular protocol of layer 2 is PPP.



  • Point to Multipoint:
A type of WAN topology where one location connects by a single physical link to multiple locations.

  • Hybrid:
A type of topology containing elements of multiple types of network topologies. It means that a network contains both point to point and point to multipoint elements.


Network Architecture:
  • Client Server Architecture:
In client server architecture there is only one node acting as a server which shares the common resources and the other node acting as client connected to the server. Client request to the server for the resources. Resources can be anything like printers and files.
  • Peer to Peer Architecture:
In Peer to Peer architecture one or more nodes acting as the server and all the other nodes request for the services to the nodes which are acting as a server. In this Architecture there is no dedicated server for sharing resources. Each node shares their resources with other nodes.

Network Types based on Geographical:

1. LAN:
LAN stands for local area network. It is the private network that connects the computer or devices in limited areas like buildings, offices or a campus. Mostly it is used to share the resources like printers, scanners and software's in the network.



2. MAN
MAN stands for Metropolitan Area Network. It is larger than LAN and it covers multiple cities or towns. Below we see four different buildings in Chicago, we've got the John Hancock Center, the Willis Tower, the Chicago Board of Trade, and the Tribune Tower. And the service provider could have different clients within these different buildings, and there's probably other buildings as well.



3. WAN:
WAN stands for Wide Area Network. It is larger than LAN and MAN and it covers multiple countries or continents. It is more expensive and a single organization might not have WAN. It is mostly managed by satellites.



4. CAN:
CAN stands for Campus Area Network. It is larger than LAN but smaller than MAN. It connects the nearby buildings. Some organizations have multiple cities in the same town so we can use CAN in such situations.

5. PAN:
PAN stands for Personal Area Network. It is smaller than LAN mostly it covers small distance like if you are using television with remote or Bluetooth comes under the PAN. It is not much high speed connection.

6. WLAN:
Before we talk about the topology that uses the physical medium to connect with one another but WLAN Wireless Local Area Network consist of three different types of topologies:
  • Ad Hoc:
In ad hoc wireless topology we don’t need any type of access medium. We just directly connect one device to the other for example if one computer wants to communicate with another computer then it sends data directly to the other computer without any wireless medium.
  • Infrastructure:
In Infrastructure wireless network we need a medium like wireless access point. If two devices want to communicate with one another then they first communicate to access point and then access point transfer the data to the receiver device.
  • Mesh:
In mesh instead of having access points we have mesh nodes that allows us to provide coverage to outdoors areas that is not terribly near the building or office. Each of these mesh nodes can communicate directly with any of the other mesh nodes, and if we're trying to communicate from one node to another node, that node that's sending the wireless transmission, it's able to run an algorithm to calculate what's the best path to get to the destination node which is gonna get out to the client.

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