2．2  缩略语    AC(Access Control List)  访问控制列表    BHCA(Busy Hour Call Attempts)    忙时呼叫尝试次数    ID(Identification)    身份证明    IP(Internet Protocol)    互联网协议    LPZ(Lightning Protection Zone)    雷电防护区    MAC(Media Access Control)  媒体控制访问    MPLS(Multi Protocol Label Switching)    多协议标签交换    MSTP(Multi-Service Transmission Platform)    多业务传送平台    NAT(Network Address Translation)    网络地址转化    NTP(Network Time Protocol)    网络时间协议    OTDR(Optical Time Domain Reflector)    光时域反射仪    PDH(Plesiochronous Digital Hierarchy)    准同步数字系列    PTZ(Pan Tilt and Zoom control)    云台操控    PRBS(Pseudo-Random Binary Sequence)    伪随机二进制序列    QoS(Quality of Service)    系统服务质量    SDH(Synchronous Digital Hierarchy)    同步数字系列    STM-N(Synchronous Transport Module level n)    同步传输模块n级    UPS(Uninterruptible Power Supply)    不间断电源    VLAN(Virtual Local Area Network)    虚拟局域网    VPN(Virtual Private Network)    虚拟专用网