I'm testing out a 93H for a Dorm type environment and have it working in tunnel mode. I've read the differences stated in this guide, referenced in other forum posts:
http://www.arubanetworks.com/pdf/technology/DG_Mobility-Controllers-Deployment-Models-5.0-VRD.pdf
After reading this, I have some questions and I'm not sure if its related to Bridge Mode, or Just limitations of equipment or just a suggestion from Aruba. In the Bridge Mode Section (Page 42) it states this:
Bridge mode allows the AP to bridge traffic directly on to the LAN, with firewall policies applied at the
AP. This deployment model is typically used in a deployment with a small number of users and APs on a
single /24 subnet. Aruba supports no more than 32 APs at a single Layer 2 network without a controller
being present and reverting to one of the other two forwarding modes.
This is not a mobility controller limitation, but a limitation in the number of devices that should
reasonably be deployed in a single Layer 2 network. Most network administrators will keep Layer 2
segments limited to /24 subnets to control broadcast domain size. This limitation fits with the expected
network size, providing approximately 222 station addresses, or approximately seven stations per AP.
As an example, where multiple buildings exist in a small area, such as a school, if each building is a
separate Layer 2 network, each building can have up to 32 APs deployed.
The APs still require access to the mobility controller to function, though the controller does not need
to be in the same location as the APs. If the mobility controller is remotely located, the APs need a
secure connection (VPN) between the sites with low latency. All processing is performed on the AP, so
certain centralized features are not available. To enable bridge mode, CPsec must be enabled in the
network.
The line that is most troubling is that last sentence of the first paragraph: "Aruba supports no more than 32 APs at a single Layer 2 network without a controller being present and reverting to one of the other two forwarding modes." I understand that a good network design has each building with a /24, but in an education community, that just doesn't work. All of my networks are /23 at the minimum and I have a couple /22, thanks to the influx of Mobile devices. A couple of my networks span several buildings, due to the small user base in those areas, however, because of Construction materials used in those areas, older buildings, the AP count is going to be much higher than 32.
Can someone clarify what this section is trying to say exactly? I guess I'm confused if this is a Bridge Mode limitation or if I'm going to hit some kind of limit or is this just a suggestion, or what. I'm looking to likely deploy around 400 of the 93H if this test proves to be good, which it is looking like it is, so any suggestions would be appreciated.
The debate I'm having with the rest of my network team currently was in regards to the Bridge vs Tunneled modes. I can see arguments both ways. Has anyone else run into this? Are the Access Switches setup in a similar fashion?
For reference, Our environment is mostly AP-105 and AP-135 Currently, Total 115 Aruba APs, Replacing a Cisco Environment of Over 500 APs. We're using a 6K controller with 1 M3 blade running 6.1.3.4, Currently. Will likely buy 2 more M3's in the next year.
Any thoughts or suggestions are greatly appreciated. Thanks.
#AP115