Flexconnect vs Local performance

[Aaron Alvarado]

Team,

I am deploying 54 3802i AP's on cisco 2504 wlc and want to get the best performance possible and wonder if, I deploy the AP's as flexconnect will give me any benefits of local switching performance boost instead of tunneling back to the wlc 1GB on local mode.

Gear:

3650's switches

3802i AP's

2504 WLC's 

Don't have the luxury of putting the AP's on 10mGig but want to get the best performance possible over 1Gb.

Thanks 

[Jonas Kalldert]

Hi Aaron,

Well it depends,

Is the APs and WLC on the same site? How much data do you think will pass throu the APs/WLC?

WLC 2504 have a maximum throughput of 1gig so if you think you will push more than 1gig total spread over all your APs then Local mode on 2504 is a nogo.

Also the 2504 have a EOL set to 2023 and the last supported version is 8.5. Maybe the 3504 could be an option if you dont already have the WLC.

Otherwise I would go with Flexconenct. Correctly setup there are no performance drops when comparing to local what I have experienced.

regards,
Jonas
**Don't forget to rate helpful posts**

[Aaron Alvarado]

Jonas,
Thanks for the reply and the AP's and WLC are at the same site. My confusion relies on the how much total throughput can 2504 deliver on 54 devices versus flexconnect. if the 2504 delivers 1GB total for all 54 devices would be extremely slow. My thought or understanding is that with flexconnect 1Gb of throuput is doable as per port.

I am only concerned with the best performance possible. in 90% favor of flexconnect but wanted to check with this will give better than using local mode

[Jonas Kalldert · Accepted solution]

Aaron,

No problem.

WLC 2504 have a total maximum of 1gb throughput. The bottleneck is that it only handles 1gb from the switch into the WLC so all the APs CAPWAP tunnels will share that 1gb. So in this case I would go with flexconnect. In flexconnect all client data traffic will be dropped directly onto the LAN and not tunneled to the WLC.

regards,
Jonas
**Don't forget to rate helpful posts**

[Scott Fella]

I wouldn’t worry about the backplane to be honest, its not like you will be pushing 1gig consistent.  Local vs FlexConnect is a decision that is made when you have reviewed what you require and the limitations to FlexConnect.  I have seen sites with 300+ ap’s on a single gig link and not more than 75% max utilization spike.  If you are worried about the backplane and your not hitting any FlexCnnect limitations, then go for it.

[Muhammed Adnan]

Hi Scott, 

As suggested by you, it would always be better to first study the deployment requirement. If for the case of APs in local mode, the wlc uplink utilization is well within the limits, then local mode could be the better choice.

Is there any means from controller to verify the %age utilization of the WLC uplink?
Through NMS we could be able to do so,  however will there be any means to check it directly from the WLC as well?

[Scott Fella]

We use snmp monitoring which can give the port utilization on the switch and also in the controller. You should be able to find an OID to look at that or use a NMS like PI or others that can give you historical data. We use SevOne for this.

[Scott Fella]

Also, Cisco did some review of this and if you look at the 5508 or the 8510 and the new models that reduced the port. The reason being is that they too collected data that shows that utilization wasn’t high. The 5520 has either two 10gig (overkill) or can be set to two 1gig. Look at that as you can have 1500 access points.

[Muhammed Adnan]

Thanks Scott for your valuable responses.

[Jonas Kalldert]

I agree with Scott that usually 1gb is enough. But it always depends on the use case. For example I'm involved in building an event where we use two 5520 in HA and about 200 APs. On that deployment we peek 7,5-8gb and have about 4-5gb constant. 

Look at your requirements and make your decision based on that.

regards,
Jonas
**Don't forget to rate helpful posts**

[Scott Fella · Accepted solution]

That is correct. Like stadium installs where you can have 50k+ users or tech events, that’s when you need to scale and choose your platform properly. I have seen hospital deployments with a single gig connection for voice and data. It’s all about gathering the requirements and procuring the correct hardware. A good example also is if you don’t plan for enough density, your AP’s will be over utilized and user experience will take a hit. When that happens, utilization is still low because devices are struggling to push their data.