Wi-Fi – Dutch-Fi

23/11/201705/02/2018

Frame classes

While studying for the CWNA and CWAP, you learn about the 802.11 State Machine. This describes the states of client connectivity during a session.

In the provided schematic there are three Frame classes mentioned.

Below an overview of these frame classes.

Class 1

Control frames
- Acknowledgement (ACK)
- CF-End
- Clear to send (CTS)
- Contention-Free (CF)-End+ACK
- Request to send (RTS)
Management frames
- Announcement Traffic Indication Message (ATIM)
- Authentication
- Beacon
- Deauthentication
- Probe Request / Response
- Spectrum Management Action. Only applicable in an IBSS.
Data frames
- Between stations in an IBSS

Class 2

Management
- Association Request/ Response
- Disassociation
- Reassociation Request / Response

Class 3

Management
- Block Ack Action
- Direct Link Setup (DLS)
- Quality of Service (QoS)
Control
- Action. Only applicable in an infrastructure BSS.
- Block Ack (BlockAck)
- Block Ack Request (BlockAckReq)
- Power Save (PS)-Poll
Data

07/08/201710/02/2018

Maximum allowed transmission power in the ETSI domain

In most Wi-Fi related documents, especially in study books, you read about the regulatory maximum allowed transmission power (EIRP) for access points.

The values described are usually based on the standards as defined by the United States Federal Communications Commission (FCC).

As a Dutch based Wi-Fi consultant these are not the values I can use as a standard for my configurations. In Europe the standard is defined by the European Telecommunications Standards Institute (ETSI).

In the following tables give an overview of the different values used in the ETSI domain.

2.4 GHz - DSSS / CCK modulation

Channel	Center frequency	Maximum EIRP
1	2412 MHz	18 dBm (63 mW)
2	2417 MHz	18 dBm (63 mW)
3	2422 MHz	18 dBm (63 mW)
4	2427 MHz	18 dBm (63 mW)
5	2432 MHz	18 dBm (63 mW)
6	2437 MHz	18 dBm (63 mW)
7	2442 MHz	18 dBm (63 mW)
8	2447 MHz	18 dBm (63 mW)
9	2452 MHz	18 dBm (63 mW)
10	2457 MHz	18 dBm (63 mW)
11	2462 MHz	18 dBm (63 mW)
12	2467 MHz	18 dBm (63 mW)
13	2472 MHz	18 dBm (63 mW)

2.4 GHz - OFDM modulation

Channel	Center frequency	Maximum EIRP
1	2412 MHz	20 dBm (100 mW)
2	2417 MHz	20 dBm (100 mW)
3	2422 MHz	20 dBm (100 mW)
4	2427 MHz	20 dBm (100 mW)
5	2432 MHz	20 dBm (100 mW)
6	2437 MHz	20 dBm (100 mW)
7	2442 MHz	20 dBm (100 mW)
8	2447 MHz	20 dBm (100 mW)
9	2452 MHz	20 dBm (100 mW)
10	2457 MHz	20 dBm (100 mW)
11	2462 MHz	20 dBm (100 mW)
12	2467 MHz	20 dBm (100 mW)
13	2472 MHz	20 dBm (100 mW)

5 GHz

Channel	Center frequency	Band	Maximum EIRP (DFS / TPC)	Maximum EIRP (no DFS / no TPC)	Maximum EIRP (DFS / no TPC)
36	5180	RLAN 1 - sub-band I (Indoor only) U-NII-1	N/A	23 dBm (200 mW)	N/A
40	5200	RLAN 1 - sub-band I (Indoor only) U-NII-1	N/A	23 dBm (200 mW)	N/A
44	5220	RLAN 1 - sub-band I (Indoor only) U-NII-1	N/A	23 dBm (200 mW)	N/A
48	5240	RLAN 1 - sub-band I (Indoor only) U-NII-1	N/A	23 dBm (200 mW)	N/A
52	5260	RLAN 1 - sub-band II U-NII-2A	23 dBm (200 mW)	20 dBm (100 mW)	N/A
56	5280	RLAN 1 - sub-band II U-NII-2A	23 dBm (200 mW)	20 dBm (100 mW)	N/A
60	5300	RLAN 1 - sub-band II U-NII-2A	23 dBm (200 mW)	20 dBm (100 mW)	N/A
64	5320	RLAN 1 - sub-band II U-NII-2A	23 dBm (200 mW)	20 dBm (100 mW)	N/A
100	5500	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
104	5520	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
108	5540	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
112	5560	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
116	5580	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
120	5600	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
124	5620	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
128	5640	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
132	5660	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
136	5680	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)
140	5700	RLAN 2 U-NII-2C	30 dBm (1000 mW)	20 dBm (100 mW)	27 dBm (500 mW)

More information can be found on the ETSI website.

2.4 GHZ – ETSI EN 300 328 V2.1.1 (2016-11)

5 GHz – ETSI EN 301 893 V2.1.1 (2017-05)

05/11/201606/02/2018

Protected Management Frames (PMF)

Protected Management Frames (PMF) is described in the IEEE 802.11w-209 amendment. PMF increases security by providing data confidentiality of management frames, mechanisms that enable data integrity, data origin authenticity, and replay protection.

This protection applies only to Robust Security Networks (RSN) and just to a subset of the management frames. The frames which are required before and during the 4-way handshake are not protected. Therefore the protection is limited to the following frames:

Channel Switch Announcement
De-authentication
Disassociation
Robust Action
- Block ACK Request / Response
- Fast BSS Transition
- QoS Admission Control
- Radio Measurement
- Spectrum Management

Another limitation is the support of this amendment on the wireless clients. The Wi-Fi Alliance (WFA) interoperability certification program requires support for PMF. However, this requirement applies only when certifying for 802.11ac. This means that there are a lot of devices which do not support PMF.

When you decide to enable PMF on your wireless network, beware of the consequences. You could potentially prevent a lot of clients from your connecting to your network. Unless you are in full control of the clients on your network and know if 802.11w is supported, my recommendation would be to disable PMF.

There are other options, such as enabling PMF as optional instead of disabled or mandatory, but I am not sure if all clients support this.

The 802.11w-2009 amendment has been superseded by the 802.11-2012 standard.