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I currently have fiber vlan trunks between all of our buildings. We are adding another ip camera server and am looking to segregate traffic. I am thinking of dedicating a fiber link and putting it on the specific ip camera vlan so traffic for the cameras in those buildings would only use that fiber and not the fiber trunk back to the main office. I have attached a a drawing of the current layout plus additional links to be added. What is the best way to do this.

proposed network layout

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    What make and model of switches are you using? How they handle Spanning Tree will greatly affect your design choices. – Brett Lykins Apr 22 '14 at 14:45
  • Core is a stack of 3 - Dell PowerConnect 7048P's. Each building has Dell PowerConnect 5548P's. – ravelsol Apr 22 '14 at 14:47
  • Why do you want to put camera traffic on separate fiber? Is it performance? Bandwidth? How many cameras do you have? I would be reluctant to do that unless there was a compelling reason. – Ron Trunk Apr 22 '14 at 16:40
  • There are over 60 cameras connected to the Packaging, Shipping, and Fiberglass switches. For bandwidth it would seem better to have there traffic go over dedicated links... – ravelsol Apr 22 '14 at 16:54
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 8 '17 at 17:51
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The short answer is, your proposed additional fiber in the diagram will not gain you any real advantage for VLAN 3.

All traffic from Packaging or Fiberglass, destined to the server in Shipping on VLAN 3, will still traverse the Core. (Presuming that you have already properly tuned your Spanning Tree settings to make the Core switch stack the root bridge.)

This is due to the Dell 5500 series switches only supporting regular 802.1D Spanning Tree and 802.1w Rapid Spanning Tree. What this means, is that in your entire switched domain in the diagram, there is only one Spanning Tree for all VLANs.


If you are set on adding additional links, and dealing with VLAN 3 in this way, you have several alternatives (viable or not, depending on your circumstances):

  1. Install switches capable of running MST (Multiple Spanning Tree), which allows you to create VLAN to Spanning Tree mappings. (Your core switches (Dell 7048P) DO support MST, but the 5548P switches do not.) You could assign all other VLANS to MST Instance 1, and then assign VLAN 3 to MST Instance 3 (instance numberings are just for example). Then you would tune the settings so that the root bridge for MST Instance 1 is your core stack, and root bridge for MST Instance 3 is the Shipping switch.

  2. Install another vendor's switches which are capable of creating a Spanning Tree instance for each VLAN. It is called different things by different vendors, PVST+ in Cisco, VLAN Spanning Tree in Juniper, etc. Similar to MST, tune the Per VLAN Spanning Tree instance for VLAN 3 to make the Shipping switch the root bridge for that instance.


With all of that said, there are still one main concern in my mind.

Why locate the server in the building with the Shipping switch? You would be better served by placing it in the main location with your Core switches.

If it MUST be attached to the Shipping switch, and you can't make changes to the switches to get a more robust Spanning Tree configuration, you still have a few options.

You could increase your bandwidth to each switch in order to handle the hair-pining of VLAN 3 traffic through the core. All of your Dell switches support LACP link aggregation, this would allow you to gain bandwidth easily between the switches to support the IP-Cameras.

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  • The Dell 5500 series switches do suppost MSTP. dell.com/us/business/p/powerconnect-5500-series/pd So it may be an option to keep those in place. The reason this server is in the shipping building is because I was trying to segregate some of the traffic. I also have some free fiber pairs between these buildings. There is another camera server in the main office where the core switch is that 80 more cameras connect too. – ravelsol Apr 22 '14 at 17:36
  • @ravelsol if I were you, I would verify that the 5500's have MST capability in their configuration (it might be software version dependent). The source of my assertion that they were not MST capable, was the actual spec sheet pdf (dated from January 2014) for the 5500 switches. I have longs since stopped trusting most vendor websites, as they tend to bend the truth more than the actual spec sheets. As for segregating the traffic, I'm still not understanding why you're attempting to do that. Are there throughput issues you're running into or anything of that nature? – Brett Lykins Apr 22 '14 at 18:07

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