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Differences Between Switches and Hubs

From N-TRON, Corp.
 

 
A hub, also known as a repeater, is a simple device that connects Ethernet nodes. Hubs forward data packets they receive from a single workstation to ALL ports. All users connected to a single hub or interconnected hubs share the same bandwidth. As nodes are added to the network, they compete for a finite amount of bandwidth (typically 10 or 100Mbs). Therefore, data collisions are guaranteed when a hub is used and network determinism (the ability to guarantee a packet is sent/received in a finite amount of time) is impossible. This is the primary reason Ethernet has had historical problems in control applications. Most control systems have a definite time requirement for packet transmission (< 100ms). This cannot be guaranteed with a hub and is highly unlikely to happen if the network is busy. You can imagine the problems this can cause in a mission critical control application. This is analogous to a single lane road. You cannot get onto the road until traffic is clear. With a hub, you cannot send a packet until network traffic is clear.
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Topics of Interest
3.9.2   The DAVID Project The DAVID (Data and Voice Integration over DWDM) project [75–78] is part of the Information Society Technology (IST) Program, a research program of the European... (Read More)
Overview of Fibre Channel Equipment Fibre Channel shares much of the same terminology as Ethernet networking with hubs, switches, network interface cards, and routers all representing a part of the... (Read More)
3.9.3   The RingO Project The RingO (Ring Optical network) project [71, 79] is carried out by a consortium of Italian Universities coordinated by the Optical Communication and Network groups... (Read More)
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