802.11b specification

I'd like to look at the specification of the packets that are sent over

802.11b. Specifically the types (data, management etc.) and so on. I downloaded a so called spec from the IEEE web site, but that was missing much more than it included, and seems to talk more about the RF than the data side.

Does any one have a suggestion where I can start?

Reply to
nigel.horne
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Base 802.11-1999 |

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802.11 related standards and updates: |
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'll also need 802.11a-1999, 802.11b-1999 and 802.11g-2003. It's all in there. Be prepared to have your brain turn to mush.

Understanding 802.11 frame types: |

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802.11 from Microsoft: |
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Wireless Site: |
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Reply to
Jeff Liebermann

I could only find parts of the specs on the IEEE site.

The problem is that my association request fails with reason 18 (required rates aren't supported by the station), even though I believe that they are. The authentication request went through OK first, so I must be doing something wrong in the association stage. I've put this into the rates field:

static const unsigned char eleven_b[] = { 3, 2, 4, 11 };

using this type of code:

frame->u.assoc_req.variable[index++] = sizeof(eleven_b); memcpy(&frame->u.assoc_req.variable[index], eleven_b, sizeof(eleven_b));

The beacon packets from the (Cisco) Access Point has 4 (i.e. 2Mb) defined twice, which is strange. I see { 4, 4, 2, 4, 11 }.

-Nigel

Reply to
nigel.horne

Ignore the 3, at the start of the array. I sent you the wrong version. It should, of course, have read:

static const unsigned char eleven_b[] = { 2, 4, 11 };

-Nigel

Reply to
nigel.horne

Ignore the 3 in the array. I sent you the wrong version. It should, of course, read:

static const unsigned char eleven_b[] = { 2, 4, 11 };

Reply to
nigel.horne

Which parts could you *NOT* find?

The beast comes in 4 parts.

- 802.11 which is 1 and 2 Mbits/sec only.

- 802.11b which extends the array to 3 (Breezecom FHSS) Mbits/sec, 5.5 and 11 Mbits/sec.

- 802.11a which again expands the field to include OFDM rates from 6 to 54Mbits/sec, and PBCC for 22MBits/sec.

- 802.11g which applies 802.11a specifications to 2.4GHz and adds an 802.11b compatibility mode.

You'll need all 4 to decode all the possible speeds. In addition, some of the chip vendors have gone off on their own and added proprietary modes. They usually default to indicating 54Mbits/sec but are running faster.

I'm going to play ignorant and pretend I don't know how to program. You might want to look at various open source implimentations on the Linksys web pile to see how it's done. The first thing I do before I scribble code is to see how the other guys do it and steal as much as possible. Maybe that's why I'm such a lousy programmist.

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Reply to
Jeff Liebermann

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