Two networks using the same switch?

[MelvinM]

I saw this today and I was not aware you could do it. Two seperate networks were using the same switch. Example 64.xxx.xxx.xx and 66.xxx.xx.xx. Both from seperate ISPs. It was a simple cisco switch, nothing tricky setup. No vlan. Just acting as a normal switch. It seems to be working, but I thought that type of setup wasn't the best idea.. that each network should use its own seperate switch.

Thanks!

 

[bcastner]

If this was a hub I would agree with you. Who needs to collision domains?

But a switch essentially cares about the MAC addresses, and really is little concerned with the TCP/IP side of the equation.

 

[opediggitty]

It is still not a good idea to to run more than one IP network over the same wire essentially, regardless if it is a hub or switch for performance as well as security reasons. The switch, even though it is looking at MAC addresses to route traffic and not flushing it out all ports like a hub, has a certain bandwidth on its backplane and when you run more than one IP network on it you are actually doubling the workload on that backplane.

 

[Morsing]

This is a pretty common setup and switches doesn't care about networks.

Cheers

Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support