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When you are learning to go the CCNA exam and make your certification, you're presented to a lot of conditions that are either completely new to you or look familiar, but you're nearly sure what they're. The definition of "collision domain" comes to the latter class for most CCNA prospects. 

What exactly is "colliding" in the first position, and why do we care? It is the information that's being sent out onto an Ethernet segment that we are worried about here. Ethernet employs collisions to be avoided by Carrier Sense Multiple Access / Collision Detection ( CSMA/CD ) in the first place. CSMA/CD is really a group of principles dictating when hosts on an segment can and can not transmit data. Ostensibly, a host that wants to send information will "listen" to the ethernet segment to see if yet another host is currently transmitting. If nobody else is sending, the number will go forward having its own transmission. 

This is an effective way of avoiding an accident, however it is not foolproof. If two hosts follow this process at the exact same time, their transmissions will collide on the Ethernet segment and both transmissions will become useless. The hosts that sent those two attacks will then send a signal out onto the phase, indicating to all other hosts that they need to not send information. The two hosts will each start a random timer, and by the end of the time the listening process will be begun by each host again. 

Given that we know what a is, and what CSMA/CD is, we need to be able to determine a collision domain. A collision domain is any area where a collision can theoretically occur, so just one device can transmit at a time in a collision domain. 

In yet another free CCNA accreditation tutorial, we found that broadcast areas were defined by routers (standard) and switches if VLANs have been defined. Repeaters and locations did nothing to establish broadcast domains. Well, they don't do anything here, either. Sites and repeaters do not determine collision domains. 

Turns do, however. A Cisco switchport is clearly its unshared crash domain! Therefore, if we have 20 variety units attached to separate switchports, we've 20 collision domains. All 20 devices can transfer simultaneously without risk of collisions. Compare this to repeaters and hubs - if you have five units linked to a single link, you still have one large collision domain, and only one unit at any given time may transmit. 

Understanding the generation and definition of broadcast domains and collision domains can be an important step toward becoming an effective network manager and making your CCNA. Most useful of luck for your requirements in both these useful passions! [http://www.entrust.net/ssl-certificates/extended-validation.htm ssl management]