There are circumstances where 802.11n devices cannot operate at their maximum capable data rates. There are various reasons why this occurs. This is the list of factors that affect 802.11n throughput:
When 802.11n clients operate in a mixed environment with 802.11a or 802.11 b/g clients, 802.11n provides a protection mechanism to interoperate with 802.11a or 802.11 b/g clients. This introduces an overhead and reduces the throughput of 802.11n devices. Maximum throughput is achieved in Greenfield mode where only 802.11n clients exist.
Factors such as Channel width, Guard Interval and Reduced IFS (RIFS) play a major role in the bandwidth.
Clients ability to send a Block Ack instead of individual frame acknowledgements.
MCS Index configured on the WLC.
Proximity to AP—Clients closer to the AP experience higher data rates. As clients move farther away from the AP, signal strength reduces. As a result, data rate decreases steadily.
RF environment—Amount of noise and interference in the environment. The less the noise and interference, the greater the bandwidth.
Encryption/ Decryption—Encryption in general reduces the throughput due to the overhead involved in the data encryption/decryption process. However, advanced encryption standards, such as AES, can provide better throughput when compared to other encryption standards, such as TKIP and WEP.
Wired Network Infrastructure—Bandwidth of the wired infrastructure determines the speed of the traffic to and from the wired network to the wireless clients.
If using an AP1250, change the AP to H-REAP mode for a 5-10% boost.
If using an AP1140, keep the AP in local mode and enable TCP MSS on the controller. Use the config ap tcp-adjust-mss enable all 1363 command in order to enable it.
Disable RRM scanning to prevent any throughput drops when going off channel. This can yield a 1-3% improvement.
Disable RLDP to ensure the AP does not attempt to connect to rogue devices during testing.
Use a Wireless Controller 5508 as the data plane is superior to the 4404-series
Transferring Crash file from standby:
Login to the Active WLC in HA.
(Cisco Controller) >transfer upload datatype crash
(Cisco Controller) >transfer upload filename <Desired filename>
(Cisco Controller) >transfer up...
This is the start of a display filter cross reference between Wireshark and OmniPeek.
The 1st installment is a table of advanced filters. More filters will be added as time allows.
It is a living doc, so check back for changes every so often
Please feel ...
I have created a Powershell script to automatically add a Wireless Guest User on Cisco WLCs. (tested on 2500 Series)
The script should be completely self explanatory.
Powershell SNMP Module (Install-Module -Name SNMP)
SNMP Write Access to...