1.6.2. Wi-Fi : Network Architecture, Protocol Stack & SSIS Management

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Complete Wi-Fi Technology Guide

Complete Wi-Fi Technology Guide

Network Architecture, Protocol Stack & SSID Management

Introduction to Wi-Fi Networks

Wi-Fi (IEEE 802.11) is a wireless networking technology that enables devices to connect to a local area network (LAN) using radio waves. This guide covers:

+-------------------------------------+
|      Wi-Fi Core Components          |
+-------------------+-----------------+
|                   |                 |
|  Network          |  Protocol       |
|  Architecture     |  Stack          |
|                   |                 |
|  - Topology       |  - Layer        |
|  - SSID Management|  Organization   |
|  - Configurations |  - Functions    |
+-------------------+-----------------+

1. Wi-Fi Network Architecture

1.1 Infrastructure Mode (BSS)

Devices connect through a central Access Point (AP):

           +---------------+
           | Access Point  |
           | (AP)          |
           +-------┬-------+
                   |
       +-----------+-----------+
       |           |           |
+------+-----+ +---+----+ +----+------+
| Client 1   | | Client 2| | Client 3 |
| (STA)      | | (STA)   | | (STA)    |
+------------+ +---------+ +----------+

1.2 Extended Service Set (ESS)

Multiple BSSs connected through a Distribution System:

+---------------+       +---------------+
| Access Point  |-------| Access Point  |
| (AP 1)        |  DS   | (AP 2)        |
+-------+-------+       +-------+-------+
        |                       |
+-------+-------+       +-------+-------+
| Client A      |       | Client B      |
| (STA)         |       | (STA)         |
+---------------+       +---------------+

1.3 Complete Network Example

+-------------------+       +-------------------+
|    Internet       |       |    File Server    |
+-------------------+       +-------------------+
           |                       |
    +------+-----------+           |
    |     Router       |           |
    +------+-----------+           |
           |                       |
    +------+-----------+ 
    |    Switch       |<-----------+
    +------+-----------+ 
           |
   +-------+-------+
   |               |
+--+---+       +---+--+
| AP 1 |       | AP 2 |
+------+       +------+
   |               |
+--+--+         +--+--+
| STA |         | STA |
+-----+         +-----+

2. SSID Management

2.1 SSID Basics

The Service Set Identifier (SSID) is the network name (up to 32 chars):

+-------------------------------+
| Common SSID Examples          |
+-------------------------------+
| "HomeWiFi-5G"                 |
| "Office_Guest"                |
| "Campus_Network"              |
+-------------------------------+

2.2 Multi-AP SSID Strategy

Same SSID across APs with different channels:

+-----------------------------------------------------+
|           Enterprise Network (Single SSID)          |
|               "Corporate_WiFi"                      |
+-----------------------------------------------------+
|                                                     |
|  +----------------+        +----------------+       |
|  |   AP 1         |        |   AP 2         |       |
|  |   Channel 1    |        |   Channel 6    |       |
|  +-------+--------+        +-------+--------+       |
|          |                         |                |
|  +-------+--------+        +-------+--------+       |
|  |   Laptop       |        |   Phone        |       |
|  | (Auto-roams)   |        | (Auto-connects)|       |
|  +----------------+        +----------------+       |
+-----------------------------------------------------+

2.3 Channel Planning

2.4 GHz Non-Overlapping Channels:
+---------+---------+---------+
| Ch. 1   | Ch. 6   | Ch. 11  |
| 2.412   | 2.437   | 2.462   |
| GHz     | GHz     | GHz     |
+---------+---------+---------+

5 GHz Channel Examples:
+-----+-----+-----+-----+-----+-----+
| 36  | 40  | 44  | 48  | 149 | 153 |
+-----+-----+-----+-----+-----+-----+

2.4 SSID Deployment Guide

Network Type SSID Strategy Channel Plan
Small Home Single SSID for both bands Auto-select
Large Office Same SSID across APs Manual channel assignment
Public Venue Separate guest SSID DFS channels where available

3. Wi-Fi Protocol Stack

3.1 OSI Model Alignment

+-------------------------------+
|      Application Layer        |
+-------------------------------+
|      Transport Layer          |
+-------------------------------+
|      Network Layer            |
+-------------------------------+
|      Data Link Layer          |
|  +-------------------------+ |
|  |     LLC (802.2)         | |
|  +-------------------------+ |
|  |     MAC (802.11)        | |
|  +-------------------------+ |
+-------------------------------+
|      Physical Layer          |
|  (802.11a/b/g/n/ac/ax)      |
+-------------------------------+

3.2 MAC Layer Functions

+------------------------------+
|        MAC Layer             |
+--------------+---------------+
| CSMA/CA      | Frame Types   |
| (Collision   | - Data        |
|  Avoidance)  | - Control     |
|              | - Management  |
+--------------+---------------+
| NAV          | ACK/Retry     |
| (Virtual     | Mechanism     |
|  Carrier     |               |
|  Sensing)    |               |
+--------------+---------------+

3.3 PHY Layer Evolution

Standard Max Speed Frequency Key Innovation
802.11b (1999) 11 Mbps 2.4 GHz DSSS
802.11a (1999) 54 Mbps 5 GHz OFDM
802.11g (2003) 54 Mbps 2.4 GHz OFDM in 2.4GHz
802.11n (2009) 600 Mbps 2.4/5 GHz MIMO, 40MHz
802.11ac (2013) 6.9 Gbps 5 GHz MU-MIMO, 160MHz
802.11ax (2019) 9.6 Gbps 2.4/5/6 GHz OFDMA, BSS Color

4. Deployment Scenarios

4.1 Home Network

+-----------------------------+
|       Home Wi-Fi Setup      |
+-----------------------------+
|                             |
|  +----------------+         |
|  | Dual-Band Router|        |
|  | SSID: HomeNet   |        |
|  | - 2.4GHz: Ch.6  |        |
|  | - 5GHz: Ch.36   |        |
|  +-------+--------+         |
|          |                  |
|  +-------+--------+         |
|  | Smart TV       |         |
|  | (5GHz)         |         |
|  +----------------+         |
|                             |
|  +----------------+         |
|  | Smart Thermostat|        |
|  | (2.4GHz)        |        |
|  +----------------+         |
+-----------------------------+

4.2 Enterprise Deployment

+-----------------------------------------------+
|           Enterprise Wi-Fi Deployment         |
+-----------------------------------------------+
|                                               |
|  +----------------+    +----------------+     |
|  |   Conference   |    |     Office     |     |
|  |     Room       |    |     Area       |     |
|  |   AP: Ch. 1    |    |   AP: Ch. 6    |     |
|  +----------------+    +----------------+     |
|                                               |
|  +----------------+    +----------------+     |
|  |    Lobby       |    |   Cafeteria    |     |
|  |   AP: Ch. 11   |    |   AP: Ch. 1    |     |
|  +----------------+    +----------------+     |
|                                               |
|  All APs share SSID: "CorporateWiFi"          |
+-----------------------------------------------+

© 2025 Wireless Networking Guide. All rights reserved.

Technical documentation by Network Engineering Team

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