Hub vs Switch: Comparison And Difference Between Networking Devices

 


Hub vs Switch – which one is better? Which one should be used for faster communication? Which one is more secure? Well, we answer all the aspects of using a hub and a switch against each other in this article.
Hub was very popular before the arrival of a Switch. So, what was something special inside a Switch which made Switch so popular? We will take a look at all the differences and functional aspects between a Switch and hub.Let’s take a look:

Hub vs switch — Comparison and differences

Hub’s properties:

• Works at the physical layer of the OSI layer
• Uses ‘Store and forwarding’ when it receives a data packet
• A virtual LAN cannot be created using a hub
• Usually comes with 4 to 12 ports
• Only transmits electrical signals or the bits (relate it with physical layer)
• Does not use any software
• Does not have its own memory for memorizing the devices connected over to the network
• Cannot learn the MAC addresses and neither can forward them
• Supports Half-duplex transmission mode
• A hub has only one broadcast domain
• Cannot support Spanning tree protocol
• Packet collisions occur commonly inside a hub

Switch’s properties:

• Works at the Data link layer or layer two of the OSI model
• Uses ‘filter and forwarding’ when it receives a data packet
• A virtual LAN can be created using a Switch and it can also work as a multi-port bridge
• Usually comes with 24 to 48 ports
• Transmits Frames (layer 2 packets) and Layer 3 packets of the OSI model
• Uses its software for admin access and other configurations
• Has its own memory for memorizing the devices connected over to the network
• Can learn the MAC addresses and stores those addressed in a CAM (Content Addressable Memories)
• Supports Half as well as full duplex transmission mode
• A hub has only one broadcast domain
• Can support Spanning tree protocol
• No packet collisions occur commonly inside a hub

Working differences — Hub vs  switch

Before you proceed to further reading, have a look at the basic concepts of the different networking devices and hardware types — hub, switch, router, modem, bridge, repeater.
Let’s say a few computers are connected to a hub in one of the scenarios and in the other scenario, they are connected to a switch.
In the Hub’s case, when all the computers send data packets, those are copied as a signal at the different ports of the hub. That means, the hub simply replicates the signal and the intended recipient gets the packets. Since there is no concept of filtering the packets and forwarding those, there will be a lot of collisions as well.
When the same data packet will arrive at one of the ports of a Switch, the following generic steps will take place:

• A data packet arrives at one of the ports.
• The Switch checks of the address inside the data packet (also called as a frame of layer 2 on OSI model)
• The switch has a CAM table and it will match the address of the frame with one of the addresses of the CAM table.
• If the address matches, the switch known the particular port at which that address resides. So the Switch will forward that packet to that particular port and this is also called as ‘Filter and forwarding’ in computer networks terms
• These things are all possible because of a configuration file and memory inside a Switch which is absent in a hub.
• The network admin can configure the switch according to his preference.
• Because of the filter and forwarding, there is no collision inside a switch.

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OSI Model And 7 Layers Of OSI Model Explained

 






What is OSI model? Why OSI model is so important and what are layers and protocols in OSI model? Here we’ll answer all the questions and explain all the different layers of the OSI model in brief.
Recently, I have been writing a lot over network topology, computer networks, and network devices. However, with time, I realized that if I continue writing more networking things, I need to write about the basics of computer networking i.e. OSI model. This will help the readers to relate it with the famous OSI model and at different points.Also, When I would feel a need of guiding a reader to read about the networking basics and fundamentals like OSI model, I can simply put up a link there.
So, here I go:

What is OSI model?

The OSI model (Open System Interconnection) model defines a computer networking framework to implement protocols in seven layers. A protocol in the networking terms is a kind of negotiation and rule in between two networking entities.

Layers of OSI model:

Physical layer

The Physical layer is also called as the Layer 1. Here are the basic functionalities of the Physical layer:

• Responsible for electrical signals, light signal, radio signals etc.
• Hardware layer of the OSI layer
• Devices like repeater, hub, cables, ethernet work on this layer
• Protocols like RS232, ATM, FDDI, Ethernet work on this layer

Data Link layer

The data link layer is also called as the Layer 2 of the OSI model. Here are the basic functionalities of the data link layer:

• Responsible for encoding and decoding of the electrical signals into bits.
• Manages data errors from the physical layer
• Convers electrical signals into frames
• The data link layer is divided into two sub-layers
  • The Media Access Control (MAC) layer
  • Logical Link Control (LLC) layer.
• The MAC sublayer controls how a computer on the network gains access to the data and permission to transmit it.
• The LLC layer controls frame synchronization, flow control and error checking.
• MAC address is a part of the layer 2.
• Devices like Switch work at this layer

Network Layer

The Network layer is also called as the layer 3 of the OSI model. Here are the basic functionalities of the network layer:

• Switching and routing technologies work here
• Creates logical paths between two hosts across the world wide web called as virtual circuits
• Routes the data packet to destination
• Routing and forwarding of the data packets.
• Internetworking, error handling, congestion control and packet sequencing work at this layer
• Router works at layer three
• Different network protocols like TCP/ IP, IPX, AppleTalk work at this layer

Transport layer

The Transport  layer is also called as the layer 4 of the OSI model. Here are the basic functionalities of the Transport layer:

• Responsible for the transparent transfer of data between end systems
• Responsible for end-to-end error recovery and flow control
• Responsible for complete data transfer.
• Protocols like SPX, TCP, UDP work here

Session layer

The Session  layer is also called as the layer 5 of the OSI model. Here are the basic functionalities of the Session layer:

• Responsible for establishment, management and termination of connections between applications.
• The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end.
• It deals with session and connection coordination.
• Protocols like NFS, NetBios names, RPC, SQL work at this layer.

Presentation layer:

The Presentation layer is also called as the layer 6 of the OSI model. Here are the basic functionalities of the presentation layer:

• Responsible for data representation on your screen
• Encryption and decryption of the data
• Data semantics and syntax
• Layer 6 Presentation examples include encryption, ASCII, EBCDIC, TIFF, GIF, PICT, JPEG, MPEG, MIDI.

Application Layer:

The Application layer is also called as the layer 7 of the OSI model. Here are the basic functionalities of the Application layer:

• Application layer supports application, apps, and end-user processes.
• Quality of service
• This layer is responsible for application services for file transfers, e-mail, and other network software services.
• Protocols like Telnet, FTP, HTTP work on this layer.

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