Wimax standards and Security The Wimax

Amitabh Mishra and Nolan Glore
CONTENTS

1. 
   Introduction 206
   
   1. 
      Standardization and Certification 206
      
   2. 
      Frequencies 207
      
   3. 
      Modes of Operation 207
      
2. 
   Frame Structure 209
   
   1. 
      Physical Layer 209
      
   2. 
      MAC Layer 210
      
      1. 
         MAC Protocol Data Unit 210
         

11.2.2.2 PMP 212
11.2.2.3 Mesh 214
11.2.2.4 QoS 214

3. 
   Security Features 215
   
   1. 
      Security Associations 215
      
   2. 
      Authentication 217
      
      1. 
         Hashed Message Authentication Code 217
         
      2. 
         X.509 Certificates 218
         
      3. 
         Extensible Authentication Protocol 219
         
   3. 
      Privacy and Key Management 219
      
      1. 
         Authorization and AK Exchange 220
         
      2. 
         TEK Exchange 221
         
   4. 
      Data Encryption 222
      

11.3.4.1 DES 222
11.3.4.2 AES 223

4. 
   Open Issues 226
   
   1. 
      Authorization Vulnerabilities 227
      
   2. 
      Key Management 227
      

References 228
205

1. 
   Introduction
   

IEEE has created a new standard called IEEE 802.16 that deals with provid- ing broadband wireless access to residential and business customers and is popularly known as the worldwide interoperability for microwave access (WiMAX). WiMAX is a nonprofit industry trade organization that oversees the implementation of this standard. WiMAX is expected to replace expensive services like cable, DSL, and T1 for last mile broadband access because it has a target transmission rate that can exceed 100 Mbps. The transmission range for WiMAX devices is up to 31 mi., which also far exceeds WiFi’s transmission range of approximately 100 m [1,2]. With such a large transmission range, a single base station may be able to provide broadband connections to an entire city.
WiMAX was designed with the ability to provide quality of service (QoS) in mind’s as a result, it can support delay-sensitive applications and services. Since it is connection-oriented, it has the ability to perform per connection QoS, allowing it to operate in both dedicated and best effort situations.
WiMAX was created to meet the growing demand for broadband wireless access (BWA). This demand has proven to be challenging for service providers due to the absence of a global standard. Currently, many service providers have created proprietary solutions based on a modified version of 802.11. Unfortunately these are costly solutions, which do not offer compatibility or flexibility. Some providers have tried to use 802.11 to implement a citywide deployment, despite the fact that it was designed to connect home or office computers over short distances.
When current WLAN technologies were examined for outdoor appli- cations, it became clear that WiFi was not well suited for outdoor BWA applications or to provide T1 level access to businesses. A technology was needed that could operate in an outdoor environment and provide T1 level services to support data, voice, video, wireless backhaul for hotspots, and cel- lular tower backhaul services. IEEE 802.16 standard was created in response to support these services, and while this standard was being defined a major emphasis was placed on the physical (PHY) layer to support an outdoor envi- ronment and on the media access control (MAC) layer to provide QoS for delay sensitive applications.

1.