PowerConnect 7048s and 8132F.

Let’s start by addressing your statements about active/passive.

The switches will have Spanning Tree on by default.  It is a protocol that is used to stop any redundant cabled paths from causing a loop and causing your switches to be overworked.  Essentially it will block the less prioritized paths (passive) until the designated (active) path goes down for some reason.

The word active in the channel-group 1 mode active command is referencing to put the LAG (Link Aggregation) into a dynamic LACP protocol state.  Instead of a static (manual) configuration.

Link Aggregation is where you have multiple physical cable acting as 1 virtual connection.  This tells spanning tree to treat all the cable connections as one connection and not block the redundant cables to the same device.  

You will set up a trunk any time that you need multiple VLANs to move across a connection.  Where it is a single cable or a LAG.

Do you have a network diagram available that we may look at?

Thanks for the explanation. Most of the concepts I was indeed aware like Spanning Tree Protocol, LAG (dynamic or static), etc.

Attached you can see the diagram. The server switches at the top currently have 5 VLANs created on them and are connected to the core as per the diagram.

What I am after is understanding how to setup the connections between all the switches. I am very confident I got it but would not mind seeing what you guys come up with!

Cheers and again thanks for the valuable help on these forums.

CR

I see that you have the core switch on the right with all the passive connections.  In order to actually get that accomplished you will need to go in and create priorities on the different connections.  Here is some information on how the port costs behave.

1,  Spanning-Tree Port Costs

    Switches all use an algorithm to determine how close they are to the root bridge. This metric is called the path cost. The lower the cost, the closer the switch is to the root. The idea is to transverse the tree using the lowest costs. What happens if two devices have identical path costs in the node of a tree? The device with the lowest MAC address value is used for the tiebreaker.

2.  Port Priority

    Spanning-Tree Port Priority influences the choice of port when a bridge has two ports connected in a loop. A lower numerical value gives that port a higher priority. This determines, between two equal cost paths, which one will be selected to be in forwarding mode, putting the other link in blocking mode.

    By calculating and assigning the port cost of the switch ports, you can ensure that the shortest (lowest cost) distance to the root switch is used to transmit data. You can assign lower path cost values to higher bandwidth ports to have them be a priority path to the root bridge

Or you may want to keep the default settings and allow the 2 core switches to load balance the traffic. Although this may take a little tweaking also to get it balanced.  The default settings take the lowest mac address and port number. This will make better use of the hardware CPUs on the devices.  Then if you were to lose a cable or switch then you would have the redundant paths to the other core switch.