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Discussion Starter · #1 ·
I was wondering if someone could give me a quick tutorial on the difference between Managed and Un-Managed Switches or confirm that my thinking is correct.

Situation 1: UN-Managed switch, computer set the DCHP. Can connect the two with Ethernet cable and will be able to "see each other" All is well.

Situation 2: Managed switch with a Port 1 addressed 192.168.1.1 Computer has a static IP of 192.168.1.1 When Ethernet cable is connected from computer to Port 1 they will be able to "see each other" All is well

Situation 3; Managed switch with Port 1 addressed 192.168.1.1
Computer has a static IP of 192.168.1.2 When Ethernet cable is connected from computer to Port 1 they will NOT be able to "see each other"


I realize that there are probably a ton of other conditions that can come into play when dealing with computer networking. I just want to make sure that I have the basics.

Thanks
 

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No to all.

Managed switches vs dumb switches the easiest way to lay it out is manages swishes have the ability to be configured. Things like QOS quality of service, security, port speed, VLANs virtual LANs. The IP addressing is not handled by the switch in normal cases. The IP addresses are either statically assigned or handed out by a DHCP server on a router. The different here is there's Layer 2 managed switches and Layer 3 where layer 3 switches can function as both a router and a switch.

An IP is not assigned to a port a managed switch however does have it's own IP so you can access and manage it however.

The next part of your question is IP addressing which is a whole separate subject. But an IP is basically a mailing address. Imagine networking as streets unless streets are interconnected or intersect you can't get to houses on other streets.

So for example 192.168.1.x is Walnut St and 192.168.2.x is Maple St.

You can live at 192.168.1.100 and a neighbor at say 192.168.1.150 and as you both live on Walnut street you can visit each other. However 192.168.2.100 is another person on another street and unless you configure your routes to allow traffic to cross between the two addresses they can't deliver to each other.

That's the very basic idea
 

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Discussion Starter · #3 ·
Edrick,

Thanks for your response!!!!

I realize that I have a ton to learn.

I am presently working on a project that has probably close to 20 managed switches, 16 fiber to copper adapters that are all managed, plus VoIP. I am not really working on the configuration of the network, however I would like to have an idea what everyone is talking about and not be completely ignorant on the topic.

I guess I have to go to Google and educate myself some.

Thanks
 

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Two more things to add, although they were alluded to. Data crashes and switch failures.

With an unmanaged switch, ie at your house where activity is relatively low, data crashes, in other words packets of data that interfere with each other, are almost never going to happen. But the larger the system, the more that likelihood increases, exponentially. That can mean that devices trying to communicate have to send, and resend, and resend, and resend data until it finally gets through. The larger the system, the worse that gets. Managed switches are like traffic cops in the street/house analogy, making sure everyone gets to their destination on time. They also can be told to let fire trucks and other important visitors through with varying levels of priority. With unmanaged switches, the garbage truck gets the same level of priority as the ambulance.

If you try to build a WAN using unmanaged switches, because lets say your traffic is low and determinism (predictable message speed) is unimportant, the other problem is if a switch fails, you have no idea. So if the system crashes, or a portion of it crashes, it can take a while to find out why. In a managed switch environment, each SWITCH, having its own separate IP, can be interrogated by the system. So if something stops working, the Central Office calls all the traffic cops on the radio and the one that doesn't respond is reported to the equivalent of the 911 operator to send an ambulance out to him (the IT guy) to see what's wrong.
 

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Discussion Starter · #5 ·
Thank You JRaef

Between you and Edrick I am starting to see why managed switches were chosen. On the process side, there is going to be approx. 10 PLC all sharing data not to mention the SCADA and Historian servers. If any part would crash the plant could be dead in water.

Once again thanks, I think that after this project is over I am going to have a much better understanding of the networking side of industrial controls.
 
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