在通信系统中，SDN 是网络虚拟化的一种实现方式，其英文全称是 ( )。当前接入互联网的重要手段之 WiFi 的英文全称是 ( ) 。

Recently,telecommunication carriers has been building ( ) core networks in order to effectively support various kinds of fixed and mobile broadband services.

When we use VolP service，the voice packets over the Internet arrive at their destination in a（ ） stream.

SMS was originally designed as part of ( )，but is now available on a wide range of networks ，including 3G and 4G networks.

（ ）was frozen in December 2008 and this has been the basis for the first wave ofLTE equipment.LTE specifications are very stable，with and added benefit of enhancements having been introduced in all subsequent 3GPP Releases.

【 The Internet ofthings (IoT) is the inter-networking ofphysical devices，vehicles ，buildings ，and other items embedded with electronics ，software，sensors，actuators，and network connectivity which enable these objects to collect and exchange data. In 2013 the Global Standards Initiative on Internet ofThings (IoT-GSI) defined the 10T as " a global infrastructure for the information society， enabling advanced services by interconnecting (physical and virtual) things based on existing and evolving interoperable information and communication technologies" and for these purposes a "thing" is "an object ofthe physical world (physical things) or the information world (virtual things). which is capable ofbeing identified and integrated into communication networks". The 10T allows objects to be sensed or controlled remotely across existing network infrastructure ，creating opportunities for more direct integration of the physical world into computer - based systems，an