무선랜 (WLAN) 의 이해 - 무선랜의 동작 원리 및 현재 사용되는 Physical and MAC Layer 표준

목차

1. Objective - 목표

2. Fundamentals of WLAN - WLAN의 기초
2.1 WLAN in Wireless Technology Category[1] - 무선 기술안에서의 WLAN
2.2 Advantages of WLAN Technologies[2] - WLAN의 장점
2.3 Shortcomings of WLAN Technologies[2] - WLAN의 단점
2.4 Standards related to WLAN[3] - WLAN과 관련된 표준기술들
2.5 Coverage Planning for WLAN [3] - WLAN을 위한 반경 설정 기술

3. WLAN operation - WLAN 동작 원리
3.1 Basic Operation - 기본 동작 원리
3.2 Distributed coordination function (DCF) - DCF
3.3 MAC Frame Structure[4] - MAC 프레임 구조
3.3.1 General MAC frame format - 일반적인 MAC 프레임 구조
3.3.2 Frame Control Field - 프레임 제어 필드
3.4 Three types of MAC Frames - 세 종류의 MAC 프레임들

4. References

본문내용

is set to 1 in broadcast/multicast frames transmitted by the AP, when additional broadcast/multicast MSDUs, or MMPDUs, remain to be transmitted by the AP during this beacon interval. The More Data field is set to 0 in broadcast/multicast frames transmitted by the AP when no more broadcast/ multicast MSDUs, or MMPDUs, remain to be transmitted by the AP during this beacon interval and in all broadcast/multicast frames transmitted by non-AP stations.
WEP (Wired Equivalent Privacy) field
The WEP field is 1 bit in length. It is set to 1 if the Frame Body field contains information that has been processed by the WEP algorithm. The WEP field is only set to 1 within frames of type Data and frames of type Management, subtype Authentication. The WEP field is set to 0 in all other frames.
Order field
The Order field is 1 bit in length and is set to 1 in any data type frame that contains an MSDU, or fragment thereof, which is being transferred using the StrictlyOrdered service class. This field is set to 0 in all other frames.
3.4 Three types of MAC Frames
- Control frames
RTS field
Figure 4.
CTS field
Figure 5.
ACK field
Figure 6.
- Management frame format
A STA uses the contents of the Address 1 field to perform the address matching for receive decisions. In the case where the Address 1 field contains a group address and the frame type is other than Beacon, the BSSID also is validated to ensure that the broadcast or multicast originated in the same BSS.
The address fields for management frames do not vary by frame subtype. The DA is the destination of the frame. The SA is the address of the station transmitting the frame.
- Data frames
Figure 7. Data Frame
The content of the Address fields of the data frame is dependent upon the values of the To DS and From DS bits and is defined in Table 4. Where the content of a field is shown as not applicable (N/A), the field is omitted. Note that Address 1 always holds the receiver address of the intended receiver (or, in the case of multicast frames, receivers), and that Address 2 always holds the address of the station that is transmitting the frame.
Table 4. Address field contents
A station uses the contents of the Address 1 field to perform address matching for receive decisions. In cases where the Address 1 field contains a group address, the BSSID also is validated to ensure that the broadcast or multicast originated in the same BSS.
A station uses the contents of the Address 2 field to direct the acknowledgment if an acknowledgment is necessary.
The DA is the destination of the MSDU (or fragment thereof) in the frame body field.
The SA is the address of the MAC entity that initiated the MSDU (or fragment thereof) in the frame body field.
The RA is the address of the STA contained in the AP in the wireless distribution system that is the next immediate intended recipient of the frame.
The TA is the address of the STA contained in the AP in the wireless distribution system that is transmitting the frame.

키워드

무선랜,   WLAN,   동작 원리,   기본 지식,   표준