HUBS in Computer network ||Aadi education

 HUBS

Hub is a network device that connects multiple ethernet devices with which they can share resources and transfer data, it works as layer 1 of OSI model of the physical layer. It amplifies and regenerates the signal too. it has many port in it so we also call it multi port repeater HUB port act as a repeater of our hub and amplify the signal and tries to send it far. Hubs connect the computers to transfer data. Hubs are not intelligent, hence they can not forward data on the basis of logical and physical address.

FEATURES OF HUB

Following are features of the network hub devices.

1. Operates in half duplex mode 

2. Available in 4 to 24 port sizes

3. host are responsible for collision detection and retransmission of packets.

4.there are three types viz. active hub, passive hub and intelligent hub.

TYPES OF HUB

There are three types of HUB.

1. Active Hub:- These hubs regenerate our signals as well as amplify the signal. Active hub need electricity to work. Active Hub is a hub that has electronic circuitry to regenerate weak signals. Active hubs function as multiport repeaters, allowing computers to be networked together in a star topology. Virtually all hubs sold today are active hubs.

2. Passive Hub:- Talking about passive hubs, it simply distributes the signal coming from the previous port. Passive hub neither regenerates any signal nor amplifies, therefore it  does not require electricity to work.

3. Intelligence Hub:- This helps the administrator to monitor network traffic, and you can configure each port on it individually, also known as manageable hub.

WORKING OF HUB

When a host send frames, the hub forwards the frames in all the ports. Hub do not separate the type of the frame, For example, whether the frame uni-cast should be either multicast or broadcast. HUBS forward all the frame into all the ports.

Although a hub sends the frames to all the ports, a computer accepts the ones, whose MAC match matches the destination MAC address field. The rest of the frames are discarded after receiving the required information.

ADVANTAGE OF HUB 

There are following benefits of hubs:

1. It can extend total distance of the network.

2. It does not affect performance of the network seriously.

3. It is cheaper.

4. It can connect different media types.

DISADVANTAGE OF HUB

Following are the disadvantage of HUB:

1. It does not have mechanisms such as collision detection and retransmission of packets.

2. It does not operates in full duplex mode.

3. It can not connect different network architectures such as token ring and ethernet etc.

4. It can not filter information i.e. it passes packets to all the connect segments.

5. It does not have mechanism to reduce the network traffic.