4.2.2 Working Principle of Hardware System ........................................................... 18
4.2.3 Introduction to Card ........................................................................................ 18
4.3 Software Architecture ..................................................................................... 20
4.3.1 Operation Support Sub-system ....................................................................... 20
4.3.2 MUX Sub-system ............................................................................................ 21
4.3.3 L2 Sub-system ................................................................................................ 22
4.3.4 NM and Maintenance Sub-system .................................................................. 22
5 Technical Indexes and Specifications ......................................................... 23
5.1 Physical Indexes ............................................................................................. 23
5.2 Basic Specifications ........................................................................................ 23
6 Operation and Maintenance ......................................................................... 26
6.1 NetNumen U31 Integrated NM Platform ......................................................... 26
6.1.1 NM Networking ............................................................................................... 26
6.1.2 NetNumen U31 NM System ............................................................................ 27
7 Comprehensive Networking Applications .................................................. 30
7.1 Community Access for Enterprise network ..................................................... 30
7.2 Corridor Access for MAN ................................................................................ 31
8 Abbreviations ................................................................................................ 32