Okay - I have to admit that this is a super high level question and topic but I hope that some of the PPCW.Net visitors and readers can answer this.
According to my server logs I have daily visitors from Nokia Networks, Ericsson Networks, Nortel Networks, Alcatel as well as from many GSM carriers from all over the world so if you are a technician, in charge for GPRS and or signalization (keyword SS7 ;-)) please read the complete story below and share your knowlede with us.
Some users from different GSM/GPRS carriers reported in several web boards (like andrew.j here in the PPCW.Net Forum) that GPRS attach disturbs the basic GSM functionalities like receiving calls or SMS:
I have recently got set up with GPRS access with my local phone operator, Jersey Telecom, only to encounter after i had used GPRS to download email or view web pages. I was unable to receive any incoming calls or SMS messages, all my calls where going direct to my voice mail, although i had ended the GPRS connection and the small G had gone from the signal strength indicator. I had a full strength indication and the operator logo was present (JT GSM). After talking to my network operator they insisted that the GPRS and GSM signals where totally separate and could not possibly cancel each other out. I have since had the GPRS removed from my account and the phone works perfectly.
Okay - for me it looks like if GPRS is attached it screws up the signalization or marks the MSISDN/IMSI as not connected in the HLR/VLR. What I completely not understand how this can happens? Basically GSM and GPRS works on different network layers so how can one screw up the other?
The only solution - some Smartphone users found so far - was disabling GPRS from their account (like andrew.j) which is completely useless if you have a data enabled terminal. Others suggested the Tanager should get a new Radio Stack to enable/disable GPRS attach.
All these solutions can't be the last word on the subject and I still don't get it how a network initiated PDP Context can disturb signalization or screw up the HLR/VLR.
I've already checked the 05.07 and 07.07 as well as the ETSI TS 101 393 without getting any hints. :-(
So now it's up to you my valuable visitors from the vendors or carriers. What's the reason, what's the result, what's the solution? Please feel free to use the comments below. Anonymous commenting is possible so you don't need to tell us from which carrier or vendor you are but it would be great if you could share your knowledge!
Cheers ~ Arne