LabVIEW
GPRS networking : Noob question
I am making a wireless remote data acqusition vi. This is not exactly a labview question, but I do know that quite a few labview guys have done wireless remote data acqusition, and like me are from engineering and non IT background, so you guys will understand my noob conceptual problem. Any experience shared will have kudos.
1. If my understanding correct for my gprs network?
I got the below ordinary USB wireless modem people normally use for internet browsing.
I plug the usb wireless modem to my laptop. I go to whatismyip.com, it shows the IP address 220.255.7.139. I type ipconfig, it shows the IP address is 119.234.164.229! So why is the two Ip address shown is different? I as a noob thinks that whatismyip.com is showing the gateway address of my usb modem gprs network visible to the internet. And ipconfig is showing the ip address of my usb modem inside the GPRS APN but not visible to internet. Is my understanding correct at this point?
2. I then unplug and plug the usb modem, check the ipconfig, and repeat. I notice each time the Ip address shown in ipconfig is different. This shows that the modem ip inside the GPRS APN is a dynamic IP, not a static IP. Is my understanding correct for point 2?
3. I unplug and plug the usb modem, and check whatismyip.com. I notice the each time ip address shown in whatismyip.com is different. This shows that my usb modem gateway is appearing as a dynamic IP address in the internet, not a staic IP as one noob would intuitively think. Is my understanding correct for point 3?
4. So below is my overall understanding of my usb modem core GPRS network architecture. Is my conceptual understanding correct?
5. So now I have a Sierra Wirelessmodem RavenXT, which manual claims that my PC vi can find the RavenXT inside the GPRS APN with the help of DDNS (dyndns.com) without the need for static IP. Well from my understanding, DDNS would only work if the RavenXT has static IP inside the APN. If the RavenXT has dynamic IP inside the APN , from my understanding above, the DDNS cannot find the dynamic IP in the GPRS APN, because dyndns.com is in the internet world, there is no DDNS in the GPRS APN. So the DDNS concept generally would not work if the office PC is to find a remote modem wirelessly and the IP addresses inside the GPRS APN are dynamic.
But however DDNS for Sierra Wireless Raven XT is used extenstively in USA. So I estimate that USA's GPRS APNs generally assign static IP inside its private network, unlike the GPRS networks my country. Is my understanding correct? What is your experience of this?
I'm no expert on these matters but I'm fairly certain that for 1 to 4 you have concluded correctly.
Not having dealt with DynDNSso far I'm not sure about the last point. DynDNS as far as I understand it, only is a simply service to register your dynamic public IP adress under a fixed DNS name, so you can refer to your dynamic IP system from the world wide web by a static DNS name. As such I'm not sure why the dynamic internal IP address should be even an issue.
Modems supporting DynDNS simply will on the assignment of a new external IP address forward that address to the DynDNS service as new address to the configured DynDNS name. If a modem doesn't support that out of the box I'm pretty sure DynDNS supports a protocol interface where you could write a small LabVIEW VI to register a new IP address for an existing DynDNS name. Maybe it doesn't even require your VI to know the currently used external IP address as it could easily see that from the originating address of the connection.
The modem itself will simply forward any incoming connection to your computer, independant of its dynamic internal IP address, provided your network rules in the modem are configured for that correctly.
