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New Member

lwapp/capwap technology clarifications

hi,

can someone help me clarify some points with capwap implementation,

does all data and control traffic tunneled back to the controller and switching packets to the specific vlan will be done by the controller?

so if i have 5508 controller, its maximum throughput will be 8 gbps (local mode AP), provided i have done LAG on all its ports to the LAN switch?

6 REPLIES

Re: lwapp/capwap technology clarifications

Hi,

You are right. All traffic is tunnled back to the WLC and the WLC put the packet in the correct VLAN.

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New Member

lwapp/capwap technology clarifications

Hello Joseph

You are correct, all the traffic that all of the access points gather is going to be tunneled to the wireless LAN controller, no matter the VLANs or the SSIDs that you have, the WLC is the device that is going to tag the packets and send it to the switch so you have to make sure that the switch is properly configured with all of the VLANs that you configured on the wireless LAN controller. The only setting that will override this behavior is the HREAP setting with local switching which will keep the traffic locally where the access point is not going back to the controller.

Also, the Link Aggregation feature will work the way you described it, it will load balance the traffic on all of the active ports on the wireless LAN controller so if you have all 8 Gigabit ports connected to 8 Gigabit ports on your switch you will have a big 8 Gbps link between your wireless LAN controller and your switch.

Here is some documentation about this:

Multiple VLANs and their behavior

http://www.cisco.com/en/US/partner/tech/tk722/tk809/technologies_configuration_example09186a00805e7a24.shtml

LAG:

http://www.cisco.com/en/US/partner/docs/wireless/controller/7.0/configuration/guide/c70mint.html#wp1277652

New Member

Re: lwapp/capwap technology clarifications

Hi Marco,

thanks for the reply, it's helpful. with the behavior the capwap has, this makes my controller the chocking point if all my AP's (200 units) at the same instant will throw data at maximum tput.

200 x 80 Mbps = 16 Gbps

can i do hreap even through the AP and the controller is on the local area network only?

Cisco Employee

lwapp/capwap technology clarifications

Each radio on AP is half duplex.

Each AP's radio bandwidth is shared no matter how many clients connected to it. Radio bandwidth is fixed.

Not all APs loaded with clients all the time sending/receiving traffic unless continous big file transfer or multicast streaming at ideal environment.

Not all APs sending/receiving at Max supported datarate all the time unless you've high density deployment with all clients closer to its APs.

AP/WLC does has certain buffer limit that can handle a bit.

On mixed G only and G/N environment through deployment or wireless client at the edge connected to G can reduce the overal radio's throughput for that AP. Same applicable for A band as well.

multicast and broadcasts are buffered at AP on dtim interval to deliver as bursts.

jumbo frames are not supported on wlc.

Having this said you can't easily reach 16 Gbps in real world.

you can't choke the 5500 with its supported AP and client limit even on its ideal environment.

New Member

lwapp/capwap technology clarifications

hi Sarav,

it may not choke the 5508 in the real world, but it may cause congestion on the 2504 with 50 AP controlled and vast traffic is going to the controller. thanks for the explanation that helps a lot.

Cisco Employee

lwapp/capwap technology clarifications

2504 is a different story, it doesn't support LAG so all the AP traffic dumped onto one physical interface only, only the uplinks can be distributed. it is a low cost software based controller. however, it will perform well at its supported AP and client limit also haven't heard anything abnormal about it if used for its purpose.

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