2. Mobile Broadband Driver Development for Windows 7
Malayala Srinivasan (Srini)
Senior Program Manager Lead
Wireless WAN - Microsoft IDC

3. Agenda Session Goals Mobile Broadband in Windows 7
Driver Design Challenges
Driver Development Stages
Call to Action

4. Session Goals
This session is targeted for the Mobile Broadband driver developer community and will:
Introduce Mobile Broadband (MB) driver development for Windows 7
Identify and prepare for key driver design areas in Windows 7
Help in getting ready for MB driver development in Windows 7

5. Terminology Mobile Broadband is also referred as
Wireless WAN
WWAN MB
VAN UI – View Available Networks UI is
Windows Vista’s “Connect to network” UI equivalent in Windows 7
Launched either through “Connect To” or “Network Tray Icon”
Mobile Broadband Driver is also referred as
IHV Miniport Driver
MB Driver
Miniport Driver

6. Mobile Broadband in Windows 7
Driver developers must use the “Mobile Broadband Driver Model Specification” for Windows 7
Supports packet-switched data connectivity over the Wireless WAN (3GPP / 3GPP2) devices
Based on NDIS6.20 miniport driver model
Control path designed for slow response devices (AT command based)
Data path optimized for Wireless WAN devices
New logo program for Mobile Broadband devices in Windows 7
New APIs for Mobile Broadband user-mode application development in Windows 7

7. Windows 7 Mobile Broadband Architecture
View Available
Network UI
Connection Flow
Experience UI
Properties UI
3rd Party
Connection Manager
Command
Line Interface
User Mode
Mobile Broadband API
Profiles
Session 0
WWAN Service
NDISUIO
Provided by:
Microsoft
ISV
OEM
IHV
Kernel Mode
Mobile Broadband Driver Model
WWAN Miniport Driver
WWAN Miniport Driver
MB Miniport Driver

8. NDIS6.20 Data Path Optimizations for MB Devices
IHV Miniport Driver
NDIS 6.0
TCP/IP Stack
Send / Receive
802.3 Frames
NDIS 6.20
IP Frames
DHCP Emulation
ARP Emulation
Windows Vista
Windows 7
Windows 7 IHV Miniport Drivers for Mobile Broadband can:
Take advantage of raw IP support in send/receive path
Eliminate DHCP and ARP spoofing in miniport drivers

9. Control Path Functionalities
Mobile Broadband Driver Model defines the following control path functionalities for the IHV drivers
Device State Management
Connectivity Management
Radio Control
SMS (Short Message Services)
PIN
Provisioned Contexts
Service Activation
Vendor Specific

10. Control Path for Mobile Broadband Drivers
WWAN Service uses NDIS OIDs for control requests (SET or QUERY) to miniport drivers.
Miniport drivers can respond asynchronously to WWAN Service.
Device state changes can be notified to WWAN service using event notification by miniport drivers

11. Asynchronous Response
WWAN Service
Miniport Driver
Designed for slow responding AT command based devices
Initiated by WWAN Service
2 Types : SET or QUERY
RequestId is Non-NULL
NdisOidRequest
Oid = OID_WWAN_CONNECT
RequestHandle = 0x
RequestId = 0x0000F00D …
AT Cmd(s) to Device
Return
NDIS_STATUS_INDICATION_REQUIRED
NdisMIndicateStatusEx
Device Responds
StatusCode = NDIS_STATUS_WWAN_CONTEXT_STATE
DestinationHandle = 0x
RequestId = 0x0000F00D
ActivationState = WwanActivationStateActivated …

12. NdisMIndicateStatusEx
Event Notification
Used for device or network state changes
Initiated by driver
Request Id = NULL
WWAN Service
Miniport Driver
Device / Network
state change
NdisMIndicateStatusEx
StatusCode = NDIS_STATUS_WWAN_CONTEXT_STATE
RequestId = 0x0
ActivationState = WwanActivationStateDeactivated …

13. 3rd Party Apps / Connection Managers
Custom IHV Features
3rd Party Apps / Connection Managers
Framework provides vendor-specific OID for driver developers to implement IHV specific features
WWAN Service provides a pass-through control path for Windows 7 applications to communicate with IHV drivers
Set VendorSpecific
OnEventNotification
WWAN Service
NDIS_STATUS_WWAN_
VENDOR_SPECIFIC
OID_WWAN_VENDOR_SPECIFIC
MB Miniport Driver

14. Driver Design Challenges

15. OID Handler Implementation
Understand AT commands and response from device.
Responding to each OID may require sending multiple AT commands to device.
Incorrect string processing in kernel mode may result in fatal failures.
See “Using Safe String Functions” in the WDK
Partner with your Connection Manager application developer or firmware engineer to get more insight on AT command semantics.
Some OID requests may require using device-specific AT commands.
Some OID responses (e.g, network error code, service activation, and raw IP handling) may require firmware changes. Partner with your device firmware team to get firmware changed.

16. Asynchronous OID Handling
WWAN Service may send multiple OIDs without waiting for the completion of the current OID request.
Driver developers should design query OID handlers to send the requests to the device without serializing.
For out-of-sequence device responses, use command tag in the response to associate the response with the corresponding request.

17. IHV and Operator-specific Commands
Use OID_WWAN_VENDOR_SPECIFIC to implement custom features. For example:
SIM Tool Kit (STK) Commands
USSD Commands
Phonebook Commands
Voice Commands
Firmware-specific commands
And more …
Use OID_WWAN_SERVICE_ACTIVATION to implement operator-specific service activation.

18. Staged Driver Development

19. Test the driver in each stage
Driver Test Tools
Use existing Connection Manager
Write simple connect / disconnect app.
WwanDriverTestApp from WDK *
Windows 7 VAN UI , Advance UI *
WwanDriverTestApp from WDK
Windows 7 VAN UI , Advance UI Mobile Broadband Logo Tests from WLK
Stage
High Level Tasks
Stage 0
Develop NDIS 6.0 driver or migrate from NDIS 5.x to NDIS 6.0 , if available
Use custom Connect / Disconnect Control OID
Test Send/Receive Path
Stage 1
Implement basic OIDs from MB Driver Model Spec.*
Test Connect / Disconnect experience with Windows 7 “VAN UI”
Make the AT command parsing implementation robust
Stage 2
Design and implement concurrent OID request handler.
Implement rest of the mandatory OIDs from MB Driver Model spec
Test PIN, roaming and profile related experience with Windows 7 UIs
Stage 3
Data Path: Migrate to NDIS Implement Raw IP support. Remove DHCP & ARP
Use MB Logo tests to find issues and fix them
Prepare for Mobile Broadband Device Logo
* Available at the time of Windows 7 Beta
Test the driver in each stage

20. Development Best Practices
Plan and implement the following items early in the development cycle of a Mobile Broadband driver :
Log the AT commands and responses in a file. Helps in debugging and root cause analysis.
Use Event Tracing to log configuration and network issues.
NdisWriteErrorLogEntry DDI for logging driver-related errors
NdisWriteEventLogEntry DDI for logging generic or network-related issues
Use the optional description member “StringsList” to log meaningful and actionable information regarding the error.

21. Call To Action
Migrate existing NDIS 5.x mobile broadband drivers to NDIS 6.0
Helps in moving to NDIS 6.20-based Mobile Broadband Miniport model.
MB devices must be NDIS 6.20-based to get logo.
Prepare for testing commercially deployed Mobile Broadband device solutions in Windows 7.
Get ready for Windows 7-based driver development.
WDK will be available at the time of Windows 7 Beta.
Review Mobile Broadband device logo requirements and send us feedback.
Contact us at

22. Resources
Mobile Broadband Logo Requirements on
Log in, click on the Logopoint link on the left side menu, and search for “MBN” requirements.
WDK Documentation on MSDN
Porting NDIS 5.x Drivers to NDIS 6.0
IP Helper
Check the Windows 7 Beta release for additional resources:
WDK documentation
Mobile Broadband Driver Model Specification
Mobile Broadband Driver Test App (WwanDriverTestApp)
NDIS 6.20
SDK documentation
Mobile Broadband API Specification
Windows Logo Kit (WLK)
Mobile Broadband Logo Tests
WHDC Web site at
Mobile Broadband Driver Development White Paper

23. Related Sessions NDIS 6.20 Overview
Day / Time
NDIS 6.20 Overview
Mon. 9:45-10:45 and Tues. 9:45-10:45
Unified Tracing and Network Diagnostics Framework
Mon. 1:30-2:30 and
Wed
Network Power Management in Windows 7
Tue. 5:15-6:15
Windows Logo Program Tests for NDIS
Mon
Wed. 9:45-10:45
Lab: How to Debug an NDIS 6.20 Driver
Mon. 2:45-3:45 and
Wed. 9:45-10:45
Discussion: Porting Drivers to NDIS 6.20
Wed. 8:30-9:30
Extending Device Installation by Using Co-installers
Mon. 4-5 and
Wed. 1:30-2:30
Using the Windows Feedback Loop to Deliver High-Quality Drivers
Mon. 8:30-9:30 and

24. Thank You!