FlexConnect L3 Roaming

[GRANT3779]

Hi Folks,

I know this has been answered but seems to be a good few years now. I also can't find any supporting documentation to say otherwise.

IntraWLC Roaming on FlexConnect SSID. If you roam between APs that have different VLANs configured for the same SSID I am assuming this is not seamless and transparent to end user? End user would have to pick up new address and go through DHCP process again and affect traffic flow?

It was answered here - https://community.cisco.com/t5/wireless-and-mobility/l3-roam-using-flex-connect/m-p/3006162#M88619

Just seeing if this is the same or if anyone knows differently?

Thanks all

[patoberli]

This answer is to my knowledge still valid and correct.
In other words, don't do it, or set the DHCP lease time short enough, so that the client can't move between the different APs (I hope buildings...) without having to automatically do a fresh DHCP.

[Scott Fella]

Patoberli is right, don't do it. First thing you need to do is look at your requirements and then understand the design that will work with your requirements. It almost seems like you are better off with controllers at the site if you plan to have the same SSID but different vlans, like when you have L3 to every floor. FlexConnect has its own requirements, which you already know and also with a limited number of access point in a FlexConnect group. So design properly by looking at the requirements and then the limitations. You might be able to adjust your design to make it work, but thats after you gather the information you or your team needs to design it properly.

[GRANT3779]

Thanks both, I'm completely against it btw from a design perspecitve. The controllers are local to the site and this would be for Corporate traffic. The only concern I had was with tunnelling everything back to the WLC and that becoming a bottleneck (9800 Controller) but the throughput is upgradeable with a software license if that becomes an issue.

For the Central Switching - Am I right in thinking there are no issues with using one large subnet for the company SSID in Central Switching. I obviously want things like collaboration apps to work between devices on wireless and also between wireless / wired. Does the WLC proxy / deal wth ARP etc from end devices..?

[Scott Fella · Accepted solution]

From my experience and talking to a lot of my customers in the past, traffic that tunnels back to the controller has not been a major issue. Cisco has also gathered data from customers and that was the decision on reducing the number of ports on the newer devices. I know back in the days, some folks would use a 2504 and run AP’s in FlexConnect because they didn’t like the throughput of the backplane. I never ran into issues with the 2504 with AP’s in local mode. You can run FlexConnect, you just have to design it protons know what is supported and what feature is not. This way the customer is also aware so down the road their are no complaints on the design.
One large subnet is fine, depending on how many clients. If you search the forum, you will get some idea of how large some subnets are and is working. We use a single subnet also no matter how large the site is and really have not ran into any issues.

[GRANT3779]

Hi Scott, great info, thanks for this.

Does the WLC proxy arp requests if we have two devices looking to talk to each other?, e.g corporate laptops.

[patoberli]

As long as it's the same VLAN, yes, the client will not see any difference between LAN and WLAN (besides the speed differences).

[Scott Fella]

There is a feature that allows peer to peer that can be enabled or disabled.