Returning to step 257, if the SIM server 26 determines the requested SIM 94 is not accessible by the SIM server 26, the method 250 passes {HEAD ~ control} to step 261, where the SIM server 26 determines whether the requested SIM 94 is accessible by {TAIL ~ other SIM servers} 26 in a same SIM server group 30 
Returning to step 257 , if the SIM server 26 determines the requested SIM 94 is not accessible by the SIM server 26 , the method 250 passes { HEAD ~ control } to step 261 , where the SIM server 26 determines whether the requested SIM 94 is accessible by { TAIL ~ other SIM servers } 26 in a same SIM server group 30
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH