about multi-RAB signalling

[a19997104]

hello all, it would be very helpfull if anyone can help me with this: during a CS call, what happens if the UE needs to enter to multirab, but the SGSN doesnt have the resources, both connections will be release, Iu-Cs and Iu-PS ¿¿ is there a 3GPP document that can give me more information about this? im checking the 25.413 but no more deep information about multirab signalling, thank you very much

[qaqa]

hello
Your RNC should first be configured to suport multi-RAB. Second, as you CS call is on going this means that ur SGSN have enough resources. when you start a paralel PS call that will be responsibility of the GGSN. If no resources availabale your PDP contect activation request should be rejected.
this is the way how I look at it.

[a19997104]

hello
Your RNC should first be configured to suport multi-RAB. Second, as you CS call is on going this means that ur SGSN have enough resources. when you start a paralel PS call that will be responsibility of the GGSN. If no resources availabale your PDP contect activation request should be rejected.
this is the way how I look at it.

hello, thank you very much for answering so quick,

- first, my RNC is huawei, it has activated the multirab, and yes, it works ok most of the time
- sometimes (most of the time with blackberry), when you have an active CS call (MSC resources), then the UE needs to establish a PS rab (due to push email maybe), i reveice a RANAP DIRECT transfer message from SGSN with the cause "resources unavailable"
- then then RNC release both, Iu-CS and Iu-PS connections, THAT i think is abnormal, it should only release Iu-PS, and continue with the CS voice call, but isntead, i have a CS drop

[dave]

Hi,
I agree with you that looks abnormal behaviour.

Anyway Direct Transfer message is not listened by RNC, just directly transferred to the UE, so no action should be taken by RNC, do you get any other RANAP message following the Direct Transfer? What does the UE reply afterwards?

Resources Unavailable for SGSN can be several reasons, but quick check is the IP pool allocated at SGSN for that APN, this could be the reason behind the unavailability.

[a19997104]

ive been confirmed that this is normal, ok the SGSN has an issue, but the RNC should release the CS call, i want to see if 3GPP says something about this...

[scorpion]

Hi a19997104,

• BBs normally establishes PDP immdly after GPRS Attach.
• Check whether your SGSN has Ciphering enabled ?
• Check whether you CS Core Ciphering ON ?

I feel with BB, The CS will fail because of existing PDP on ciphered mode and CS Call attempted without ciphering. Check this.

Is this problem, only specific to HUAWEI PS & CS Core ?