Ericsson Media Gateway

i don’t understand wher’s the problem. sd congestion is at cell level. MGW can have A 10,20..80% load there’s no difference. increase the number of SDs on congested cells that’s what we use to do if sdcch congestion is really due to traffic increase

could you check out the SDCCH average duration ? do you notice an increase here as well ?

if it is the case, then you could simply perform a drivetest in a cell with this problem, and see where is the delay : during authentication ? ciphering ? tmi reallocation ?

a sdcch phase which is too long will lead to more ocupancy –> higher congestion.

you confirm that the sdcch erlang has increased above the sdcch capacity of the cell, right ?

if you have 1000 sdcch req. and each sdcch usage lasts 3.6 seconds –> 1 erlang

if you have the same 1000sdcch requests, but due to delay in the authentication or ciphering phases (or tmsi reallo), each sdcch lasts 7.2 seconds –> 2 erlangs

the duration of the sdcch affects the occupancy of the channels.

got it ? or you need an analogy ? at the supermarket, whether each client stays 30 seconds at the cashier or 10 minutes, that will highly impact the “congestion”. The queue of clients will greatly increase if each stays 10 minutes. I can relate to that :)) i always choose the wrong queue at the supermarket.

regards,
pix

Check the number of SCCP. We experienced the same thing last time. The SCCP was not dimensioned to the network traffic.