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How can I prevent collisions on my network?

Learn about network collisions and how to prevent them with networking expert Chris Partsenidis.

How can I prevent collisions on my network? We're using extended-star topology, and after installing a 16-port switch there are fewer collisions but the network is still congested.

We have four switches with 24 ports as well as one hub with 24 ports, and it seems that the people most affected by collision are connected to the 3Com hub.

Secondly, how do I remove the domain name system (DNS) from our primary server?

The fist step in preventing collisions within your network would be to remove all hubs; they are simply a source of problems and nothing more.

When a frame enters a hub it will exit out all ports, creating unnecessary traffic on your network; whereas a switch will only send the frame out of the correct port -- where the destination machine resides. All ports on a hub belong to the same collision domain; conversely, on a switch each port belongs to one collision domain.

In many cases, I've seen problematic hubs generate garbage traffic that would affect most workstations and servers on the network, so keep away from them.

Secondly, you've got around 120 ports available on your network, which is a fairly large amount for one flat network. I usually start to break networks with more than 50 hosts into smaller segments in order to avoid broadcast/collision problems.

It might be a good idea to look into breaking the network into smaller pieces, using widely known Virtual Local Area Networks (VLANs). With VLANs, you effectively create smaller, separate networks and join them using either a router or Layer 3 switch.

If you're interested in learning more about VLANs and how you can connect them between each other, you can visit my website, where the topic is analyzed extensively.

You also mentioned that you wanted to remove the DNS server from your primary server. Depending on your network setup, this might not be a good idea, especially if you're running Microsoft Active Directory which requires the DNS service in order to function correctly.

However, if you've got a workgroup, then moving the DNS server to a different machine shouldn't be that much of a problem.

This was last published in July 2008

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