COMPUTER NETWORK HUB

A computer network hub is a basic networking device that connects multiple computers or other network devices together allowing them to communicate with a local area network (LAN).

There are several types of computer or network hubs and they are; passive, active, intelligent or smart, switch and dual-speed hub.

A passive hub simply connects cables together with no amplification, processing or power supply. It acts as a pure wiring concentrator. Examples of passive network hubs include; 10base-T wiring concentrators, BNC coaxial T-connectors/vampire taps, token ring passive MAU (multi-station access unit), simple punch down patch panels etc.

An active hub (multiport repeater) regenerates and amplifies the incoming signals before broadcasting it to all ports. Examples of active network hub includes; net gear EN10STP, 3COM office connect hub 8, Cabletron systems MR9T-series hub, D-link DE-805TP, Bay Networks 10 base-T hub, IBM 82222 workgroup hub etc.

An intelligent or smart hub includes all active hub features plus management capabilities such as monitoring, diagnostics and some level of traffic management. Examples of intelligent or smart hub includes; 3com super stack II hub 10, Cabletron systems MMAC-plus, cisco catalyst 1000 series, bay networks lattis hub 28115, HP advance stack 10 base-T hub, synoptics lattis net model 2813 etc.

A switching hub is a transitional device that combines hub architecture with some switching intelligence. It can direct traffic more efficiently than a pure hub but is essentially an early generation network switch. Examples of a switching hub includes; Kalpana etherswitch EPS-700, 3com LANplex 2500, cisco catalyst 1900 series, bay networks 28200 series, DEC GIGA switch etc.

A dual speed hub supports two different speeds on the same device, commonly 10mbps and 100mbps allowing legacy devices to coexist with faster ones. Example of dual-speed hub includes; net gear DS 108, net gear DS116, 3com office connect dual speed hub 8, D-link DFE-905 dual speed hub, Linksys EFA-H08W, Intel netport express dual speed hub etc.

The advantages of computer network hub are; they are simple, cheap and easy to install. They work seamlessly with virtually any network device and are ideal for packet sniffing and analysis. They are also very useful for network monitoring. Network hubs require no memory or processing overhead for address learning. Active hubs extend cable range by regenerating signals or by signal amplification.

The disadvantages of computer network hub are; all traffic goes to all devices regardless of destination, resulting in bandwidth waste. All devices share one collision domain causing frequent packet collisions. Their performance degrades badly as more devices are added. They are not designed to filter, prioritize or direct traffic and any device on the hub can see all network traffic (easy to sniff). They cannot send and receive simultaneously hence further limit their speed of operation. They cannot segment traffic logically and are obsolete in speed (most hubs cap at 10-100mbps).

Computer network hubs find applications in the following; network analysis and trouble shooting, small home and office networks, labs and testing environments, industrial and legacy systems and network tapping and mirroring.

The future of computer network hub depends on the advances and development of the following technologies; the emerging trends in network hubs are smart/managed switches; software defined networks (SDN) which allow the use of software to dramatically manage traffic flow across the entire network; wireless access points will enhance faster, more flexible and cable free connectivity. The future will see the advent of USB-C and thunderbolt docking stations with devices that expands a laptop ports. Cloud managed networking platforms like cisco meraki and ubiquiti uniFi would manage entire networks from the cloud, eliminating the need for any standalone hub era thinking.

 

SOURCES:

• Computer networks by Andrew S. Tanenbaum and David J. Wetherall.
• Data communications and networking by Behrouz Forouzan.
• Building a network: A practical guide by Scott Mueller and Terry Williams Ogletree.
• Introduction to networking by Dave Holzner.
• Local area networks by Patrick Regan.