"Wireless Modem" vs "Modem link" vs "internet sharing"

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stw303

Member
May 30, 2006
46
15
Taradale
Guys,
Like a lot of people here, I sometimes use a Notebook PC to connect to my work over VPN via my Universal. I've always used "Modem Link" as it was more reliable than "Wireless Modem".

In the most recent WM6 Roms, "Modem Link" seems to have disappeared, replaced by "Internet Sharing".

My Telco, like a lot of others, uses a NAT'ed IP address to provide GPRS/3G internet connectivity. "Internet Sharing" also uses IP NAT'ing to share the Telco's IP address. This creates a situation where you are NAT'ing a NAT'ed IP address.

To explain further:
1) Real internet ip address: 203.134.56.123
2) It is then NAT'ed by Telco and becomes 10.0.0.1
3) It is then NAT'ed again by "Internet Sharing" to become 192.168.0.1


This situation is fine for normal web browsing, but won't work when using a VPN client(ie: Cisco). Most VPN clients wont tolerate Double-NAT'ing.





Has anyone experienced this scenario?

Are there alternatives to "Wireless Modem" & "Modem Link"?

Is there a "Modem Link" cab floating around that can be installed separately on the newer WM6 ROM?

Or is there any way to get "Wireless Modem" working reliably?



Thanks,
Simon
 

beast0898

Senior Member
Jan 5, 2006
813
2
Milton Keynes
Guys,
Like a lot of people here, I sometimes use a Notebook PC to connect to my work over VPN via my Universal. I've always used "Modem Link" as it was more reliable than "Wireless Modem".

In the most recent WM6 Roms, "Modem Link" seems to have disappeared, replaced by "Internet Sharing".

My Telco, like a lot of others, uses a NAT'ed IP address to provide GPRS/3G internet connectivity. "Internet Sharing" also uses IP NAT'ing to share the Telco's IP address. This creates a situation where you are NAT'ing a NAT'ed IP address.

To explain further:
1) Real internet ip address: 203.134.56.123
2) It is then NAT'ed by Telco and becomes 10.0.0.1
3) It is then NAT'ed again by "Internet Sharing" to become 192.168.0.1


This situation is fine for normal web browsing, but won't work when using a VPN client(ie: Cisco). Most VPN clients wont tolerate Double-NAT'ing.





Has anyone experienced this scenario?

Are there alternatives to "Wireless Modem" & "Modem Link"?

Is there a "Modem Link" cab floating around that can be installed separately on the newer WM6 ROM?

Or is there any way to get "Wireless Modem" working reliably?



Thanks,
Simon

Hi,

WModem will be in my latest release with Laurentius, due for release on 1st November.

The problem with most of the current releases that include it, is that the reg on the PDA does not have the correct settings to report the driver name to the windows machine (the entries have been left as generic)

I have just tested WModem and it works fine, over USB.

Cheers,


Beasty
 

stw303

Member
May 30, 2006
46
15
Taradale
Hi,

WModem will be in my latest release with Laurentius, due for release on 1st November.

The problem with most of the current releases that include it, is that the reg on the PDA does not have the correct settings to report the driver name to the windows machine (the entries have been left as generic)

I have just tested WModem and it works fine, over USB.

Cheers,


Beasty
Thanks Beast. That makes a lot of sense.

Now for the most obviouse question. Any chance of making a WModem CAB files with those reg settings? Or even easier, list the relavent reg keys and the correct values.



Thanks again,



Simon
 

beast0898

Senior Member
Jan 5, 2006
813
2
Milton Keynes
Thanks Beast. That makes a lot of sense.

Now for the most obviouse question. Any chance of making a WModem CAB files with those reg settings? Or even easier, list the relavent reg keys and the correct values.



Thanks again,



Simon

Hi Simon,


This should be all you need to change to allow the emulation to be correctly detected by your PC............ I assume you have the PC driver and dialer.

Unless the Rom you are using has more missing.

[HKEY_LOCAL_MACHINE\Drivers\USB\FunctionDrivers\USBSER_Class]
"Manufacturer"="CDMA1X USB Modem"
"Product"="CDMA1X USB Modem"

Cheers,


Beasty
 

Jwrightmcps

Senior Member
Mar 13, 2005
294
0
Chicago, IL
Hi Simon,


This should be all you need to change to allow the emulation to be correctly detected by your PC............ I assume you have the PC driver and dialer.

Unless the Rom you are using has more missing.

[HKEY_LOCAL_MACHINE\Drivers\USB\FunctionDrivers\USBSER_Class]
"Manufacturer"="CDMA1X USB Modem"
"Product"="CDMA1X USB Modem"

Cheers,


Beasty

These are the actual required OEM settings:

[HKEY_LOCAL_MACHINE\Drivers\USB\FunctionDrivers\USBSER_Class]
"Dll"="serialusbfn.dll"
"DeviceName"="USBFNS2:"
"Prefix"="COM"
"DeviceArrayIndex"=dword:1
"RxBufferSize"=dword:4000
"IClass"=multi_sz:"{CC5195AC-BA49-48a0-BE17-DF6D1B0173DD}","{C375C787-B721-4b8e-B67F-A112D5C0A404}"
"idVendor"=dword:0bb4
"Manufacturer"="HTC"
"idProduct"=dword:0cf
"Product"="HTC USB Modem"
"bcdDevice"=dword:90
"Tsp"="Unimodem.dll"
"DeviceType"=dword:0

Also note that the only important keys for driver identification are:
"idVendor"=dword:0bb4
"idProduct"=dword:0cf

These two keys make up the "VID" and "PID" that windows uses to match all drivers to PNP hardware (AKA "Device Instance ID" and "Hardware Ids"). Without the proper VID and PID windows will never match the Modem to the drivers that are provided.

If you want to review it for yourself, just open the modem driver (USBMDM.INF) file and look for the "[HTC]" tag. See below for example:

%USB\VID_0BB4&PID_00CF.DeviceDesc% = Modem1, USB\VID_0BB4&PID_00CF

Hope that helps you guys...

-Jwrightmcps
 
Last edited:

cranticumar

New member
Apr 23, 2008
3
0
Hi Beasty, Simon

I am very much familiar with Internet Sharing

I want to know how a modem link works.

Like I have gone to Modem link application and

Selected USB as my connection ans have provided my Access point specified by my Service provider.

Pressed the activate. Status has become Active.

After this, how to browse Internet over my PC.

No Network has been detected by My PC.

Please reply me as soon as possible so that i can move further with my proceedings

Thanks
Kranthi Kumar