通过Um接口监测仪表观察,可能观察到的GPRS ATTACH信令流先后顺序是()
- AATTCHREQUEST-SECURITYFUNCTION-ATTCHACCEPT-ATTCHCOMPLETE
- BATTACHREQUEST-SECURITYFUNCTION-ATTACHCOMPLETE-ATTACHACCEPT
- CATTACHREQUEST-ATTACHACCEPT-SECURITYFUNCTION-ATTACHCOMPLETE
- DSECURITYFUNCTION-ATTACHREQUEST-ATTACHACCEPT-ATTACH