Hub

Before a couple of years, we used to despair and panic in an event of power cut. These days the same happens when the internet connection goes down! It seems as if we and all of the myriads of our devices are jacked into the internet at all times. Without the connectivity to this vast network we find our ‘smart’-phones dumber than dumb! Yes, this sure is an era reigned by the might of computer networks. The complexity involved in a network such as the internet is unnerving. It is hard to find a standalone system today. Therefore, it makes sense to state that the technicians of the previous decades would find them jobless and hapless in todays networked world. Along with a strong understanding of individual components that make up a standalone system it is instrumental for us to know how a network works and the devices used to make that network function as it ought to!

Working principle of device:

A hub is an Ethernet network (IEEE 802.3) connectivity device. It is a single point of attachment for all the devices on a network. It works at the Physical layer of the OSI model (Layer 1). An array of RJ-45 ports is available to connect the network devices in a physical star, logical bus topology. Since hub is only a multi-port repeater it creates a logical bus topology where data flows to every host on the network even if it is physically connected in a star topology. A LAN (local area network) needs to be segmented into smaller parts to prevent it from slowing down. This process is called network segmentation. However, hubs are dumb devices and will NOT aid in making a network work efficiently.

But a huge LAN may still pose a variety of problems. Firstly, LAN is limited to a certain number of hosts (each individual terminal on a network). So it isn’t possible to connect a large number of hosts to a single LAN. To solve this issue, segments can be created and then interconnected with a device like hub (Note: you are strongly advised against using hubs for this purpose, the reason for which will be addressed in the tutorials on switch and router). With each segment having the maximum possible hosts the total number of hosts on the LAN will be equal to the number of segments times the maximum permissible number of hosts per segment. Segmentation can also help segregate the network based on its functions. For example, the HR department will have totally different tasks to perform than the sales department. Hence it seems logically more compelling to group the HR department and sales department separately and then connect them over a link. When each network segment is protected by its own firewall the risk of the entire network getting infested or compromised in any possible way reduces dramatically.

 A switch or a router is always preferred over a hub as they segment the network but when budgets are stringent it is better to be lame than to be disabled! Hub is basically a multi-port repeater. It will amplify the frame received and copy it to all other ports except its source. It doesn’t perform any kind of intelligent switching or routing. A hub cannot be used to connect multiple networks together. It can only be used to connect LAN segments together. A frame can be sent out to all hosts on a network (broadcast) or to a specific host (unicast). Without looking at the header to check whether it is a broadcast or a unicast, the hub will forward all frames to all hosts on the network (the hub doesn’t break up collision domains and broadcast domains, which is why it doesn’t segment networks!). This creates a problem of congestion on a network. Congestion leads to failed transmissions (at a time only one host can transmit and so collision occurs when multiple hosts transmit) and low bandwidth. Thus the overall performance of a network deteriorates. But Hallelujah! Switches and Routers at rescue!!!

Hub in the ultimate analysis is a god forsaken piece of shit that can find a place only in the sacred networking archives of the ancient civilizations!

Device installation: Simply connect Ethernet patch cables from the host to the hub and power it on. The network will be down and choked up in no time! Thanks to its intelligent behavior!

Standard Configuration of device: Hubs working at various speeds are available to suit the needs of the network. The common speeds are 10Mbps, 100Mbps fast Ethernet and 1000Mbps Gigabit Ethernet. Dual speed hubs supporting more than one base speeds are also available. Some families are simply more abundant than the others. Similarly, some hubs simply have more number of ports on them than the others!

Market share of different models (Standard companies only):

It is extremely rare to find hubs these days. Switches have largely superseded these notorious devices!

Hubs and switches look identical on the outside!