Looking for design principles in regards to a Campus Area Network? We are a medium sized company with < 250 employees spread across 4 offices. We will soon be combining 2 offices into 1 larger campus.

  • Should we utilize L2 or L3 for WiFi in each building? Since the buildings will all be close in proximity together and have outdoor APs I want to make sure any staff/guest can connect in any building without being disconnected when roaming around the campus. We will utilize the same SSID for staff connections across the entire campus. Currently we have Ruckus Wireless gear for the WiFi.
  • I understand keeping L2 networks small to keep down broadcast traffic. Would there be any major downfalls to spanning the L2 network between all buildings on campus? Splitting up different departments and services onto different VLANs.

Since the new offices have not been built yet I want to get things planned for the best availability of growth.

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    Commented Aug 10, 2017 at 15:37

3 Answers 3


I like to keep broadcast domains the "standard" /24, that has always worked fine for me. Separating departments into different /24's is a good idea, that makes your firewall rules and ACLs easier. Printers and other garbage I like to put into a different L2 network just to keep things tidier. Management traffic into another as well. L3 roaming is nice on WiFi since you can keep the department/subnet logic working there as well then. Remember to leave room for growth between your networks, for example allocate a /22 for each department and assign them the first /24. If that department grows, you can easily allocate another /24, and if you did everything right, you don't need to change any firewall rules.


This is a good question as this scenario covers tens of thousands of businesses. Following the KISS principle is always a good idea. You want the LAN to be a LAN. So, you want all VLANs available to all switches. Practically, this means uplinks (links connecting switches) are trunk links. This way, if you ever need to put a port on the OUTSIDE VLAN, for example, all you gotta do is assign that port to that VLAN.

As for WiFi, I recommend sticking with a layer 2 implementation unless you have a solid reason not to. Again, WiFi is layer 2 connectivity so leave it as such.

As for VLAN's and WLANs (SSID's), keep them to a minimum. You should not need more than 4 or so VLANs - maybe INSIDE, OUTSIDE, DMZ, GUEST. INSIDE and GUEST WLANs (SSIDs).


This will provide a good baseline for everyone of your requirements, however small or large your campus is. http://www.cisco.com/c/en/us/solutions/enterprise/design-zone-campus/index.html

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    Commented Feb 20, 2016 at 3:54

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