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Capturing wifi traffic with Cisco Aironet access point.

Capturing wifi traffic with Cisco Aironet access point. published on No Comments on Capturing wifi traffic with Cisco Aironet access point.

It is possible to use Cisco Aironet as wifi sniffer. The device can operate in monitor mode and sending packets to specified destination. This is implemented by WIDS (Wireless IDS?) protocol.
In this case, the packets were capturing using Wireshak. I configured access point to work in monitor mode and to send packets to my computer on address and on 5555 port.

Now device sends packets to my computer, I can launch Wireshark and see them. There is need to set proper packets decoding as CWIDS.


Additionally I set filters to only see traffic from the access point.


It is important to note, that the device is able to monitor only one channel in the same time, but channel can be easily changed: 

802.11n vs 802.11ac performance comparison – cisco aironet 2600, 2700 series

802.11n vs 802.11ac performance comparison – cisco aironet 2600, 2700 series published on No Comments on 802.11n vs 802.11ac performance comparison – cisco aironet 2600, 2700 series

It will be my first post on this blog 🙂

Today I want to show my tests of two wireless access points. The short specification of this two devices presents as follows:

air-cap2602i-e-k9802.11N – Cisco Aironet 2600 series AIR-CAP2602I-E-K9 with autonomous ap IOS software 15.3.3-JC
“802.11n with 3×4 multiple-input multiple-output (MIMO) technology with three spatial streams, which sustains 450-Mbps rates”
Full spec: Link

air-cap2702i-e-k9-1802.11AC – Cisco Aironet 2700 series AIR-CAP2702I-E-K9 with autonomous ap IOS software 15.3.3-JC
“802.11ac with 3×4 multiple-input multiple-output (MIMO) technology supporting three spatial streams. This architecture offers a sustained 1.3-Gbps rates”
Full spec: Link

So both devices have 3×4 spatial stream. The main purpose of this test is to show performance diffrence between 802.11N and 802.11AC wireless standard. The differences between the two standards in the brief are:

    – the width of a channel, 802.11N supports up to 40Mhz channel while 802.11AC (phase 1) support up to 80Mhz, and for phase 2 of this standard it is 160Mhz. Cisco Aironet 2700 is a 802.11AC phase 1 device.
    – the modulation, 802.11N supports up to 64-QAM, for 802.11AC it is 256-QAM

As wireless client I will use notebook Dell Latitude e7240 with Intel 7260AC wireless card which has 2×2 spatial stremas. The notebook is running under Opensuse Linux 13.1 with 4.2.5-1 kernel version and iwlwifi-7260-15 firmware for wireless card. Unfortunately I do not have device supporting 3×3 spatial stream.

Let’s get to the test…

I set radio interface on both devices like shown below.
Cisco Aironet 2600:

Cisco Aironet 2700:

For performance testing I use iperf3 between two computers. One of them is connected by gigabit ethernet to the access point, and the second (Dell Latitide) is connected to the wireless network. It looks like below.
Let’s see how the connection looks, when I connect notebook to Aironet 2600. The distance between devices is about 2 meters. I’ll check the statistics of wireless interface in notebook.

I am especially interested in two parameters – txrate, rxrate. It look’s very good, the Intel 7260 wireless card achieved maximum connection bitrate for 2×2 spatial stream device in 802.11N standard – 300Mb/s Rxrate and 300Mb/s Txrate.
Now I launch iperf to see how the performance looks, when device passes real TCP traffic.
On the server I started iperf which is listening for incomming connections on 8888 port.

I’m going to perform download test. On the client I launched iperf in 10 processes to simulate 10 tcp sessions:

and upload:

Wow! 🙂 220 Mb/s download and 172 Mb/s upload speed. In my opinion these are very good results for 802.11n standard.

Let’s check the 802.11AC with Aironet 2700. The connection status on Dell Latitude is showing:

Despite the short distance connection parameters were not as stable as in the case Aironet 2600. I do not know why Intel 7260 did not achieve full rate, which is 866Mb/s Rx/Tx Rate for 2×2 spatial stream client on 80 Mhz channel width. I saw 866Mb/s rates only temporarily. In Addition, there was a problem with the client connection which was hanging up every minute. I solved this problem by remove 802.11d configuration.

I do not understand why it had such an impact. These settings works well in 802.11N.

But, how real speeds I can achieve in iperf test with Aironet 2700?
Download speed:

Upload speed:

442 Mb/s download and 298 Mb/s upload speed.
Nice, almost half gigabit per second. But I was expecting a better result in spite of twice the width of the channel and denser modulation in 802.11ac

That sums up.
Is it worth to upgrade wireless infrastructure from 802.11N to 802.11AC?
It depends on your needs. 802.11N is still fast enough for most applications, and it is stable. But if you work with tasks which are generating heavy network traffic, such as copying big files over local network, you should consider switch to 802.11AC.