802.11b Receiver

802.11b Receiver

Listen to 802.11b channels 802.11b receiver (bbn_80211b_rx.py)

Identify the type of received frame

2

802.11 MAC Frame Format

3

Frame Control

Duration/ ID

Address 1

Address 2

Address 3

Sequence Control

Address 4 Data CRC

2 2 6 6 6 6 2 4 0-2312 bytes

Protocol version

To DS

More Frag Retry

Power Mgmt

More Data WEP

2 2 4 1 From DS

1

Order

bits 1 1 1 1 1 1

Type Subtype

MSB LSB

Special Frames

4

Frame Control Duration

Receiver Address

Transmitter Address CRC

2 2 6 6 4 bytes

Frame Control Duration

Receiver Address CRC

2 2 6 4 bytes

Frame Control Duration

Receiver Address CRC

2 2 6 4 bytes

ACK

RTS

CTS

802.11b Receiver

~/bbn_80211b/src/examples/bbn_80211b_rx.py Tune to 802.11b channels To identify the received frame type, the bbn_802.11b_rx.py

needs to be modified (ex) $./bbn_80211b_rx.py -f 2.412G b v

5

Lab homepage http://monet.postech.ac.kr/class/lab/ example result

802.11 MAC Frame

6

802.11 MAC Frame

7

802.11b Channels

8

Channel Lower Frequency Center Frequency Upper frequency

1 2.401 2.412 2.423

2 2.406 2.417 2.428

3 2.411 2.422 2.433 4 2.416 2.427 2.438

5 2.421 2.432 2.443

6 2.426 2.437 2.448

7 2.431 2.442 2.453

8 2.436 2.447 2.458

9 2.441 2.452 2.463

10 2.446 2.457 2.468

11 2.451 2.462 2.473