谁能帮忙给翻译一下这句话？谢谢！

If there is no MS-VLR/SGSNsignalling after the initial L3 signalling message sent from MS to VLR/SGSN, i.e.in the case of deactivation indication sent from the MS followed by connection release.
整句话是什么意思？
其中的L3 signalling message指什么？

层三信令--please check cdma2000 system architecture reference