- This topic has 5 replies, 1 voice, and was last updated 8 years, 4 months ago by pix.
10th September 2012 at 11:01 #68551MahmoudGuest
Do you know the situations that BSC send PAGING OVERLOAD to MSC? And what action should be done by MSC?
Mahmoud14th September 2012 at 09:47 #68552MahmoudGuest
Any body can help please?15th September 2012 at 09:58 #68553pixGuest
I wasn’t aware of such message, it’s interesting.
Paging overload is probably a BSC defense mechanism. The BSC has a paging processing limit, which is usually reached when you mapped too many LAC in your BSC.
for example :
BSC 1 = LAC 1, 2, 3, 4, 5, 6
BSC 2 = LAC 1, 2, 3, 4, 5, 6
BSC 3 = LAC 1, 2, 3, 4, 5, 6
Each BSC is handling 6 LAC. That means that the MSC is sending a lot of pagings to each BSC.
If you do something like this :
BSC 1 = LAC 1, 2
BSC 2 = LAC 3, 4
BSC 3 = LAC 5, 6
then each BSC is still handling the same amount of cells, and each cell is still sending the same amount of pagings (1/6th of the whole network pagings, assuming the 6 LAC have equal size)
but each BSC is handling 3 times less pagings -> the paging processing is much less than before.
pix15th September 2012 at 20:40 #68554TanujGuest
If the no. of cells is very high in one LAC then BSC sends this message to MSC, we dealt with this problem by splitting the LAC in the BSC16th September 2012 at 15:57 #68555MahmoudGuest
Thanks for your help.
I found bellow description which can be useful for others, so I share with you:
in 220.127.116.11 of TS 48008. Brief description of the algorithm is provided as follows:
1. A total of 15 flow control levels are available.
2. The MSC first starts T5 (30s). In the period specified by T5, the system does not change the flow control level. After T5 expires, the system starts T6 (also 30s).
3. In the period specified by T6, if the system receives an Overload message again, it decreases the flow control level by 1 and restarts T5. If T6 also expires, the system increases the flow control level by 1 and restarts T5.
4. The preceding steps occur alternatively. To prevent restriction of all services, level 1 is set as the lowest flow control level. When the flow control level increases to level 15, the system ends flow control.
The flow control algorithm aims to protect the BSC against soaring traffic
Mahmoud19th September 2012 at 19:45 #68556pixGuest
cool, thanks for the info.