CompTIA Network + Exam Certification Exam Tutorial:
The Star Topology
By Chris Bryant, CCIE #12933
To pass the Network+ exam, you've got to master the details of the various network topologies in use today. Every topology has its benefits and drawbacks, but some have more benefits and some have more drawbacks! In today's Network+ exam tutorial, we'll take a look at star networks.
You know how you really have to use your imagination when you look at a constellation and you're supposed to see a big water dipper, or a little water dipper? You'll have to use your imagination to see a star here, but this is a star topology:
We've got a switch in the center of this star topology, but we could also have a hub. You should know that the switch drawing shown here is universal, so if you see a 3D square with those arrows on top, that's a switch!
The star topology has better fault tolerance than a bus, but that's not saying a lot. If the cable connecting Host A to the switch goes down, the ability of the other hosts to transmit data is unaffected. Obviously, Host A will not be able to transmit.
Star topologies still have a single point of failure, though, and that's the device that connects the "points" of the star. If the switch goes down, no host will be able to successfully transmit data.
Other benefits of the star topology:
- When workstations are connected to their own switch ports, they can send data at any time, regardless of whether hosts connected to other switch ports are transmitting at the same time.
- Star topologies are highly scalable. In the network we've been discussing, as long as you've got a switch port that's not in use, you can easily add hosts to the network without impacting other hosts.
A "drawback" to star topologies is that they do require more cable than a bus topology. It's good to know that theory, but in the real world, a lack of cable is rarely if ever going to stop you from implementing a star topology over a bus. You're going to see more star topologies than any other in today's real-world networks.
In contrast, you don't see a lot of ring topologies out there anymore, but just in case you bump into one on your Network+ exam or in a real-world network, you better be ready... and you will be after reading my next Network+ exam tutorial!
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To your success,
Chris Bryant
CCIE #12933
chris@thebryantadvantage.com
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