- This topic has 6 replies, 1 voice, and was last updated 11 years, 9 months ago by Pan.
6th July 2009 at 09:08 #57807FahimGuest
I m in urgent need of an answer :
A5/2 is activated at BSS (Alcatel)
No ciphering on MSC (Huawei)
What is the impact ? Is encryption working properly ?
If we want to change from A5/2 to A5/1 what could be the possible impacts on the network ?6th July 2009 at 15:16 #57808PixGuest
MSC vs. BSC… Pan can certainly help you ? I don’t know. The MSC is very important for ciphering, without it i don’t see how ciphering would work.
A5/2 –> A5/1 : it is a good move, but you need to configure your AuC accordingly.7th July 2009 at 05:41 #57809PanGuest
Dear, Fahim! Appropriated ciphering algorithm activation is required on MSC also. Without this there is no ciphering at all in your network (because MSC commands to BSC by means of CIPHER MODE COMMAND to start ciphering and indicates the supported algorithms. The BSS then selects an appropriate algorithm, taking into account the MS ciphering capabilities).
It was many complaints from subscribers (without A5/2 support) in our network when it supported A5/2 only. But I didn’t face with mobiles that doesn’t support A5/1.21st July 2009 at 02:12 #57810FahimGuest
Can you plz tell me whether signalling load on SDCCH increases significantly if there is cipheirng ?21st July 2009 at 08:04 #57811PanGuest
Hi, Fahim! Not significantly, but it is increased on period of time between Ciphering Command from BSC to MS and Ciphering Complete from MS to BSC.21st July 2009 at 08:16 #57812PixGuest
But even without ciphering, it means the ciphering is actually A5/0. In this case, isn’t there still a cipher command which contain the ciphering A5/0 ?
But using ciphering is mandatory since it’s the only way to avoid anyone being able to eavesdrop on any conversation in your network.
If some people from your government or from companies are using your network, they wouldn’t be very happy if they knew their calls are not protected.22nd July 2009 at 03:24 #57813PanGuest
Hi, Pix! Yes you are right, but I have only said that Ciphering procedure makes a contribution in SDCCH signalling load:) and without that procedure the SDCCH signalling load would be less.