New Switch integrated into System creates Connection Failures

[dt2009]

Hi Everyone,

good day to you all, i have  3 running switches currently, two 24-port J92085A and one 48-port J9280A switches, these 3 are all connected to each other, now i tried setting up another switch (DELL) on another floor and plugged that into floor tank leading to the patchpanel and from there into the main switch (the 48-port J9280A ). When i do that suddently the 2 24-Port Switches can not be accessed via browser/IP any more and they get a an error saying "Lost connection to multiple devices on port # " causing many machines to loose their network connection. Has anyone ever experienced similar problems? I have no clue why this is happening?

Lots of thanks in advance for taking a look at this, with best wishes from here and a great day to you all,

cheers

dt

[IanV]

Howdy,

Chances are that the introduction of the new switch on your network has created a loop that is creating a broadcast storm and is bringing your network down. Ugh.

You either need to make sure that there are no loops in your network or need to read up on spanning-tree protocols and how they can be used to prevent loops. Hopefully the Dell switch can be made to be interoperble with your HP ones and they can all play nicely.

The HP's will run MST (google it) out of the box which is why you probably didn't have a problem until the DELL came along. If the DELL can have STP switched on that would be good - even better if it can run MST. If it already running some flavour of STP we can move on...

The HP switch that sits underneath your WAN gateway should have its spanning tree priority lowered (google it)  such that it becomes the focal point for the rest of the network to converge upon. This configuration will make this switch the "root bridge" (yep, google is your friend). This basically means that you force the network to respect your wishes when it comes to how the redundant links should arrange themselves. In other words you rather than the switches decide who's boss and where the "top" of the network is.

Best of luck !

Ian