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would it cause any delay or troubles in communication if we mixed network ranges in the same stiches?

like we have 172.16.X.X along with 192.168.X.X adresses in the same auto negotiating unmanaged switch!

It really shouldn't. You should be fine. Even a cheap modern switch has a huge capacity. However, broadcast requests will be sent and heard from both.

Really screwy packets being formed, broadcast storms, attacks, etc are possible between networks. For example, I've seen a windows computer that had 2 IP addresses bound to the same adapter magically lock up a clunky embedded NIC on an NMR machine. If you're really security conscious you might separate your networks between switches or VLANS.

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Nathan Boeger
http://www.inductiveautomation.com
Total SCADA freedom

It shouldn't cause any problems if the switch is unmanaged. The machines use ARP [0] to find the other hosts' IP addresse on the same network. With a
managed switch you can make VLANs and in some cases access control lists to enhance security. Your setup isn't ideal, but you shouldn't have any problems.

HTH,

~ sh

Why would you not want to use a router for this purpose? After all, thats what they are designed for!

A good design aspect would be to segregate your domains via a router and then plug the respective ranges into seperate switches. Check out HARTING for a comprehensive range of Ethernet switches.

You would use a Layer 3 switch as opposed to a router. They're really very similar except that the router does it in software and the switch does it with hardware (ASICs). The advantage of a "smart" switch is that you can logically define "networks" (VLANS) that can't communicate with each other directly. These can be based on physical ports or MAC addresses. You can assign logical gateways in the switch that act as routers like you're referring.

A router is going to be better suited for connecting large networks (huge cached routing table) and providing security (if it has a firewall or policies built in).

A managed switch will be better for creating "separate" networks for you to use.

Again, the "gotcha" from a security geek or hypothetical situation is separating broadcast domains.

Hope this helps,

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Nathan Boeger, MCSE
http://demo.inductiveautomation.com
Total SCADA Freedom

Using different networks through a single switch is not a problem, but it's not advisable, two broadcast domains would fall into the same switch. It has to be separated through VLAN based switches or to have a router to do so.

You might run into trouble with netbeui if any of your computers use it.

Tomy Zacharia