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I was doing a bit of reading over the months on some of the intricate detail of 802.11 standards just to refresh on some wireless to wired troubleshooting with our protocol analyzer. As I age, I find it difficult to keep all the acronyms straight in networking .Much like in basic networking where we have learned to remember the 7 layers of the OSI model from top to bottom with a catch phrase of All People Seem To Need Data Processing. I have found a child-like way to help recall with the MAC -DATA (Layer 2) and PHY (Layer 1) of 802.11 wireless standards. At the MAC and PHYSICAL layer in the 802.11 standards we have these sometimes confusing terms with Service Data Units and Protocol Data Units.

Here goes...

The secret weapon is found in the friend or villain of Lois Lane, and the strength or weaknesses of SUPER-MAN and/or SPIDER-MAN. Huh? What you talking about Reggie? Holy Smokes Batman!? No Batman took a day off. Let me break it down for you. This may awaken your wireless ?¡é?€??Spidey Senses?¡é?€??. Sometimes, at least for me, it gets a bit confusing which one of these takes precedence. This is where the term SUPERMAN and SPIDERMAN may clear the airwaves for you.

In the OSI model, after Layer 7 (Application) and Layer 6 (Presentation); at Layer 5 (Session) , the letter S comes before the letter P Layer 1(Physical). The Session Layer can handle things like whether or not the operation is full or half-duplex above Layer 4 (Transport). We know that wireless operation in 802.11 is half duplex with CSMA/CA. But I have an easier way of remembering the MSDU, MPDU, PSDU and PPDU and the sequencing of them through the layers. This can be found in the spelling of the words SUPER and SPIDER--- S also comes before P. If we were to break either of these super heroes down they have hidden powers and vulnerabilities that may further help you understand wireless. OK, let?¡é?€??s investigate.

At the Logical Link sublayer of the MAC (Layer 2) is where the journey of the wireless super heroes begins to make a little sense for some. I would like you to think of Lois Lane as the Logical Link Control (LLC) of both SUPER and SPIDER men. Mary Jane took a break with Batman?  She holds the key for them getting to the layers above 3 and providing the lower level at the PLCP sublayer a protocol that is dependent (PMD) on how the MAC operates.

She can just SNAP her fingers to empower Super-man or when he flies to the PLCP sublayer he can be zapped of his powers with the ?¡é?€??Kryptonic powers?¡é?€?? of Radio Frequency Interference and Packet Error rates from him trying multiple times to access the airwaves .

Lois knows: each one of these men needs to access the network layer through her and because of his super human physical strength he acknowledges Lois Lanes presence with Service Data Units and Protocol Data Units.

MAC- Layer 2
E- Ethernet -Layer 2 (802.3)
Network ?¡é?€?¡°Layer 3

Each Service or Protocol unit at MAC (Layer 2) needs to be SUPER or a SPIDER to get to either the Network (Layer 3) or RF Medium or Physical (Layer 1).

(LLC) ?¡é?€?¡° Lois Lane?¡é?€??s control to your news-work (NETWORK) (Daily Planet or the Daily Bugle) at Layers 3, 4, 5, 6, 7 on the wired side.

|
MAC
Service
Data
Unit
|
MPDU (MAC Protocol Data Unit)
|

PHYsical
Service
Data
Unit
|
PPDU (Physical Protocol Data Unit) ?¡é?€?¡° Layer 1 (RF- Wireless)

In effort to clarify even further the data units, I have broken SUPER and SPIDER into a helpful anagrams that can be used to define or recall some of the functions of 802.11.

SUPER:

Service (MSDU) (PSDU)
Units
Protocol (MPDU) (PPDU)
Ethernet- Layer 2 (MAC)
Radio- Layer 1 (PHY)


SPIDER:

Service (MSDU) (PSDU)
Protocol (MPDU) (PPDU)
Identical (PSDU and MPDU)
Data (LLC) or MAC
Ethernet -Layer 2 (MAC)
Radio- Layer 1 (PHY)


There you have it, a way to play upon 802.11 standards that involves something that you might be familiar with. I could go on an with this branching off with the word SUPER-MAN and SPIDER-MAN as an elaborate labyrinth with the ?¡é?€??Divinci Code?¡é?€?? for 802.11.

We all have our various study methods and perhaps of using these childhood comic book characters will help some of you grasp the concepts in your studies for the CWNP certifications.