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FlexConnect in a local network

B A
Level 1
Level 1

Hello,

 

I have basic knowledge of FlexConnect and when it's used - branch offices and remote sites. Recently I've been told by some auditors that we should configure FlexConnect in our local network to increase wireless speed and quality. I've never heard of using it in a local network. Does it make sense to enable FlexConnect in a local network? 

 

Thank you for any feedback.

 

Btw. we have one WLC and 70 APs.

 

42 Replies 42

saravlak
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out of curiosity, the existing setup is Aireos or ios-xe based. If Airos, first thing to be done is to migrate to ios-xe.

are auditors talking about SD-Access and not traditional flex connect by any chance.

B A
Level 1
Level 1

@patoberli There currently is no circumstance to do this, as long as the bandwidth between all APs and WLC is large enough to cope the full expected traffic.
This is what I needed to hear. Do other experts agree on this too? 

 

@balaji.bandi you can use any netflow and NMS to Monitor
Do you recommend any? We use Zabbix but I am not able to make it work. Any other alternative? Where can I see these numbers in WLC?

 

@Scott Fella Out of curiosity, have you made a decision or done any further testing?
I've made my decision but I am collecting more info for my manager. Now I am going to monitor traffic from/to WLC to verify that WLC uplinks can handle all the traffic. I would test FlexConnect on APs only in case they would insist on configuring it.

 

@saravlak We have 3504. As long as it's supported, we stay where we are. 

Do you recommend any? We use Zabbix but I am not able to make it work. Any other alternative? Where can I see these numbers in WLC?

I use Prime Infrastructure. I wouldn't anymore buy this as a new product. 

Cisco by now uses a mostly standard netflow format, but make sure your software actually supports Cisco WLC Netflow:

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-8/AVC_8point8_dg.html#pgfId-81615

 

I've made my decision but I am collecting more info for my manager. Now I am going to monitor traffic from/to WLC to verify that WLC uplinks can handle all the traffic. I would test FlexConnect on APs only in case they would insist on configuring it.

As stated many times, FlexConnect is very rarely needed if you don't transfer the data over WAN links. Depending on the size of your network (amount of APs) and the small 3504 WLC, you might saturate the 1 Gbps port. You can work around that by enabling LAG on more ports on the 3504, that way you can increase the throughput further: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-5/b_WLC_3504_Release_8_5_Deployment_Guide.html

 

Nowadays in most enterprise developments your AP density is fairly high, so that all clients have a strong signal with a short path to the AP. That way you can get a lot of performance out of your network, while providing good roaming. The big downside of this is the channel re-use. For this reason you often have 40 or even 20 MHz channels on 5 GHz, to maximize the amount of free channels. But this will vastly reduce the maximum throughput if no users are there (capable client assumed), but will vastly increase the throughput if many users are there.

In other words, with a 160 MHz 802.11ax channel (which limits you to 2 or 3 available channels), you could have > 1 Gbps of throughput with a single capable client. If you reduce this to 20 MHz you now have around 19 available channels, but a maximum throughput of maybe 250 Mbps. Those numbers are sadly only valid if there are no other wireless devices on the same frequency, which sadly doesn't happen in the real world, unless you are in a cellar For this reason you never really reach the high bandwidth when using 80 or 160 MHz channels, as you have way to much co-channel interference and noise which will lower the real throughput. Please note, those channel numbers are for the USA, there are various regulations over the world. In some places you only have one 160 MHz channel, or two/three 80 MHz ones. 

B A
Level 1
Level 1

Nobody?

Again, what else are you looking for here? This is a pretty long thread and the decision is up to you.
-Scott
*** Please rate helpful posts ***

B A
Level 1
Level 1

patoberli wrote: There currently is no circumstance to do this, as long as the bandwidth between all APs and WLC is large enough to cope the full expected traffic.
Do other experts agree on this too? 

Agreed. 

And in fact there may be specific reasons for needing the traffic to be centrally switched like features which are not supported on flexconnect local switching.

https://www.cisco.com/c/en/us/td/docs/wireless/access_point/feature-matrix/ap-feature-matrix.html

B A
Level 1
Level 1

Well, we've been monitoring traffic on WLC ports and I see these values (per second):

Avg. Sent:150Kbps

Avg. Received: 2Kbps

Are these numbers relevant? They seem pretty low.

If those numbers are correct, then there is virtually no wireless traffic at all.

B A
Level 1
Level 1

Are these numbers real/correct when 300 devices are connected?

It looks like all the Internet traffic doesn't go by default through WLC and just the management traffic does.

Can anyone clarify this?

For fairly live statistics you can enter the following command:

(Cisco Controller) >show stats port packets 5
Link n secs n secs InPktRate OutPktRate InDataRate OutDataRate
Pr Status Pkts In Pkts Out (pkts/sec)(pkts /sec)(bytes/sec) (bytes/sec)
-- ------ ------- ------- ------- ------- ---------- -----------
1 Down 0 0 0 0 0 0
2 Down 0 0 0 0 0 0
3 Down 0 0 0 0 0 0
4 Up 4 7 4 7 676 762
5 Up 2011 535 2011 535 422208 254098
Total 2015 542 2015 542 422884 254860
Interval(n): 1 Seconds

The number at the end is the port on the WLC. It shows how much data was transmitted the last one second. In my case 422 KB/s from switch and 254 KB/s to switch.

And here while running a speedtest:
(Cisco Controller) >show stats port packets 5
Link n secs n secs InPktRate OutPktRate InDataRate OutDataRate
Pr Status Pkts In Pkts Out (pkts/sec)(pkts /sec)(bytes/sec) (bytes/sec)
-- ------ ------- ------- ------- ------- ---------- -----------
1 Down 0 0 0 0 0 0
2 Down 0 0 0 0 0 0
3 Down 0 0 0 0 0 0
4 Up 12 18 12 18 8567 2151
5 Up 41941 71468 41941 71468 47030096 50446188
Total 41953 71486 41953 71486 47038663 50448339
Interval(n): 1 Seconds


Now it was around 47 MB/s and 50 MB/s.

More info:
https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-10/cmd-ref/b-cr810/show_commands_r_to_z.html#wp3247135730

B A
Level 1
Level 1

Thanks. This is what I was looking for. I see 40-60Mbps InDataRate and 20-40Mbps OutDataRate. Still, I think this is ok. Do you agree?

 

Probably, I have absolutely no idea what kind of clients do you have, if the normal number is on-site (home office Corona ...?), what the typical traffic is that you have and and and. This is a very individual number for every company.
But if you say that you currently have the normal number of clients on-site and they normally use the wireless, then yes this number is ok.
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