Another layer 2 device, the switch, is rapidly replacing the hub at the layer 1 level. Recently, this higher performance device has been dropping rapidly in price, making it a cost effective choice to improve network performance.
Many switches look just like hubs theyre boxes with 4, 8, or more ports, often-attaching cables with RJ-45 connectors. The difference is in functionality. Instead of repeating all the traffic out to all cables connected to it like a hub, a switch makes a virtual circuit between the sending and receiving devices, which stays up long enough for the traffic to pass. Like a bridge, it keeps track of which hardware MAC addresses are associated with each port, and sends out traffic only to those ports for which it destined. In this way it is similar to a router on the 3rd layer, the difference being that a switch directs traffic among devices on a single LAN, and a router directs traffic among multiple LANs.
The advantages of a switch over a hub are:
Home - Table Of Contents - Contact Us
CertiGuide for Network+ (http://www.CertiGuide.com/netplus/) on CertiGuide.com
Version 1.0 - Version Date: November 7, 2004
Adapted with permission from a work created by Tcat Houser and Helen O’Boyle.
CertiGuide.com Version © Copyright 2004 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.