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Understanding an APs 802.11 MAC counters output

Does anyone know if Cisco have any guidance on troubleshooting AP throughput and interpreting the 802.11 MAC counter statistics ?

2 ACCEPTED SOLUTIONS

Accepted Solutions

Re: Understanding an APs 802.11 MAC counters output

Hi Ashley,

802.11 MAC Counters

The following table describes the 802.11 MAC counters.

Table 2-2    802.11 MAC Counters
Counter

Description

Tx Fragment Count

This counter is incremented for an acknowledged MPDU with an individual address in the address 1 field.

Tx Failed Count

This counter increments when an MSDU is successfully transmitted after one or more retransmissions.

Multiple Retry Count (Graphics view only)

This counter shall increment when an MSDU is successfully transmitted after more than one retransmission.

RTS Success Count

This counter increments when a CTS is received in response to an RTS.

ACK Failure Count

This counter increments when an ACK is not received when expected.

Multicast Rx Frame Count

This counter increments when a MSDU is received with the multicast bit set in the destination MAC address.

Tx Frame Count

This counter increments for each successfully transmitted MSDU.

Multicast Tx Frame Count

This counter increments only when the multicast bit is set in the destination MAC address of a successfully transmitted MSDU. When operating as a STA in an ESS, where these frames are directed to the access point, this implies having received an acknowledgment to all associated MPDUs.

Retry Count

This counter increments when an MSDU is successfully transmitted after one or more retransmissions.

Frame Duplicate Count

This counter increments when a frame is received that the Sequence Control field indicates is a duplicate.

RTS Failure Count

This counter increments when a CTS is not received in response to an RTS.

Rx Fragment Count

This counter shall be incremented for each successfully received MPDU of type Data or Management.

FCS Error Count

This counter increments when an FCS error is detected in a received MPDU.

WEP Undecryptable Count

This counter increments when a frame is received with the WEP subfield of the Frame Control field set to one and the WEPOn value for the key mapped to the TA's MAC address indicates that the frame should not have been encrypted or that frame is discarded due to the receiving STA not implementing the privacy option.

I think the Band Select statistics speak for themselves ...

When the feature is activated, the WLC doesn't immediately reply to probe requests on 11b/g. If immediately a probe is also seen on 11a, then the clietn is detected as dual band. Then WLC only replies on 11a. After some time, this "categorization" expires and WLC will again try to see if the client is present on both bands.

Re: Understanding an APs 802.11 MAC counters output

Yes, for once that the Help page is actually helpful .... ;-)

5 REPLIES

Re: Understanding an APs 802.11 MAC counters output

Hi Ashley,

can you be a bit more specific ?

AP throughput is best tested with Iperf tool. The max throughput with 11g APs is 19 Mbps more or less.

11N APs have more varying factors. I have never seen more than 180Mps on a 11N running on 300mbps data rate.

Which MAC counters are you exactly wondering about ?

Nicolas

New Member

Re: Understanding an APs 802.11 MAC counters output

Hi Nicholas,

                 I am referring to the AP stats you get shown from a WLC.  I use MONITOR > Access Points > 802.11b/g/n and then select "detail" from the blue drop down arrow on the far right hand side of each AP shown in the list.

   At the bottom of this screen are the "802.11 MAC counters" stats and "Band Select Statistics"

I'm trying to find information on Cisco about the figures and the meaning of each category.....

Re: Understanding an APs 802.11 MAC counters output

Hi Ashley,

802.11 MAC Counters

The following table describes the 802.11 MAC counters.

Table 2-2    802.11 MAC Counters
Counter

Description

Tx Fragment Count

This counter is incremented for an acknowledged MPDU with an individual address in the address 1 field.

Tx Failed Count

This counter increments when an MSDU is successfully transmitted after one or more retransmissions.

Multiple Retry Count (Graphics view only)

This counter shall increment when an MSDU is successfully transmitted after more than one retransmission.

RTS Success Count

This counter increments when a CTS is received in response to an RTS.

ACK Failure Count

This counter increments when an ACK is not received when expected.

Multicast Rx Frame Count

This counter increments when a MSDU is received with the multicast bit set in the destination MAC address.

Tx Frame Count

This counter increments for each successfully transmitted MSDU.

Multicast Tx Frame Count

This counter increments only when the multicast bit is set in the destination MAC address of a successfully transmitted MSDU. When operating as a STA in an ESS, where these frames are directed to the access point, this implies having received an acknowledgment to all associated MPDUs.

Retry Count

This counter increments when an MSDU is successfully transmitted after one or more retransmissions.

Frame Duplicate Count

This counter increments when a frame is received that the Sequence Control field indicates is a duplicate.

RTS Failure Count

This counter increments when a CTS is not received in response to an RTS.

Rx Fragment Count

This counter shall be incremented for each successfully received MPDU of type Data or Management.

FCS Error Count

This counter increments when an FCS error is detected in a received MPDU.

WEP Undecryptable Count

This counter increments when a frame is received with the WEP subfield of the Frame Control field set to one and the WEPOn value for the key mapped to the TA's MAC address indicates that the frame should not have been encrypted or that frame is discarded due to the receiving STA not implementing the privacy option.

I think the Band Select statistics speak for themselves ...

When the feature is activated, the WLC doesn't immediately reply to probe requests on 11b/g. If immediately a probe is also seen on 11a, then the clietn is detected as dual band. Then WLC only replies on 11a. After some time, this "categorization" expires and WLC will again try to see if the client is present on both bands.

New Member

Re: Understanding an APs 802.11 MAC counters output

Hi Nicholas,

                 I've just found exactly what you provided and thank you for the quick response.

I forget that the actual HELP pages on the Wireless LAN Controller itself can often give you more information than what you find on Cisco.

Thanks for you investigative efforts, good job.

Regards

Ashley

Re: Understanding an APs 802.11 MAC counters output

Yes, for once that the Help page is actually helpful .... ;-)

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