I recently passed my CCNA and got a "entry level" position as a Network Technician. I think some of the configurations I am asked to do are not so entry level and I have very little help from colleagues unfortunately. At any rate, I am wondering if anybody out there can help me with a problem I am facing. I was asked to setup and create a new VLAN. Sounds simple right? Well, this is the setup as far as I understand it...

My setup:

"Switch A" is a Cisco switch (not sure what model off the top of my head). This is the switch that some DVR type devices for surveillance purposes will be connected to. The company I am working with would like a new VLAN setup on their network for these DVRs that can be accessed from any of their locations, throughout the country, which are connected to each other over an MPLS. Switch A is connected to a layer 3 Cisco switch, I believe, and that layer 3 switch is configured as the VTP server and in turn is connected to a SonicWALL firewall (NSA 4500).

What I have done so far:

I created the VLAN (named DVR on VLAN 9) on the layer 3 switch and VTP propagated that VLAN to Switch A. On Switch A I added the access ports to the DVR VLAN that need to be part of that VLAN. That's it. I am not sure where to go after this.

Some more information:

This VLAN needs to provide DHCP services to the devices connected to it. At a very minimum I would like to know how to get the VLAN up and running at
least on the local network and worry about crossing the MPLS another time. So what do I need to configure on the layer 3 switch and the firewall?

My question is this:

How do I configure the VLAN on this equipment to get the VLAN traffic to route through the network properly? The layer 3 switch and firewall are causing some confusion in my head.

Let me know if you have any questions or would like running configs. I would be truly grateful for any help you can provide. Thanks in advance.