The ITU s TMN (Telecommunications Management Network) Recommendations
The ITU's TMN (Telecommunications Management Network) RecommendationsM.3000 through M.3600 describe network management in terms of FCAPS:
The Web-Based Enterprise Management (WBEM) group of the Distributed Management Task Force (DMTF) created the common information model (CIM), which uses the universal modeling language (UML) to define the data that may be used by the CMIP, CORBA, and XML systems described below. The TeleManagement Forum also addresses operations systems with a top-down perspective. Many major network operators use an ad hoc collection of network operations systems that have little or nothing in common with ITU (TMN) or TM Forum standards. Many of the legacy OSSs predate TMN. For some major network operators, this consists of network elements (NEs) with associated element management systems (EMSs) where the NE and EMS are provided by the same equipment vendor, and the EMS usually manages many NEs of the same type. The EMS usually performs the following functions with the NE: alarm surveillance, testing, provisioning, and performance monitoring. The EMS is considered to be a tier-1 management system, and may connect to "tier-1.5" service management system (SMS) or a tier -2 network management system (NMS). The TMN standards defines Q3 as the interface between the NMS and the EMS. The International Standard Organization (ISO ”www.iso.ch) defined a TMN-based OSS software structure that includes a service layer protocol (CMISE: common management information service element) and presentation layer protocol (CMIP: common management information protocol). CMIP-CMISE has seen little adoption by the industry. Instead, CORBA (common object request broker architecture) from the Object Management Group (www.omg.org) has been widely adopted by the industry. CORBA is an open object-oriented software architecture for distributed OSS systems that enables applications from different vendors to interwork via networks. CORBA uses the standard IIOP protocol and the interface description language (IDL) to define interfaces. Three principal languages are used for communications between operations systems: TL1, SNMP, and XML. TL1 (transaction language one) has been used for many years by the legacy telco operations systems such as TIRKS, NMA, and LMOS. Additional functions, such as managing new types of NEs, usually require new TL1 messages and updates to the necessary operations systems. Updates to the operations systems can be expensive and time consuming. Updates to Telcordia (formerly Bellcore) operations systems use a process called OSMINE. Simple network management protocol (SNMP) management systems originated in the world data networks. HP-Openview was one of the first SNMP based management systems. SNMP is based upon access to standardized information records termed management information bases (MIBs). SNMP-v1 is widely used for alarm surveillance and monitoring. SNMP-v2 added much needed security features, but its complexity caused SNMP-v2 to be unpopular. Recently, SNMP-v3 has added provisioning capabilities and the security functions have been simplified. SNMP-v3 is expected to gain widespread use. SNMP management systems are object oriented and thus are comparatively easier to update and expand. Extensible markup language (XML) has recently been introduced for electronic data interchange (EDI, also known as electronic bonding), and was derived from hypertext markup language (HTML). XML is primarily used for automated service negotiation between CLECs and ILECs. Network management architecture (NMA) is the principal OSS used for telephone network alarm surveillance and performance monitoring. NMA was developed by Telcordia. TL1 interfaces from the network elements to convey alarms: critical loss of service to many lines, major loss of service to a few lines, and minor impaired service. NMA also collects E2A relay contact closures that indicate environment conditions: fire, high water, door open, loss of primary power, low battery. A fault in one network element can result in the trouble being detected in associated network elements and at several layers in each element. With TL1, each layer of each element can report faults, and thus a phenomenon know as an alarm storm can result where one fault can cause many alarms. NMA contains a root cause analysis function that determines the origin for related alarms. Special services (not locally circuit switched, e.g., HICAP, DDS) are tested using digital test systems such as SARTS (special access remote test system ”Telcordia), the Teradyne test system, and Hekimian-REACT that perform digital loop-backs and measure bit error rates. The digital transport test systems often gain access to the circuit via a digital cross-connect system (DCS) such as Titan (Tellabs) and DACS (Lucent). Subscriber lines for circuit switched services (POTS and ISDN) are tested by the loop maintenance operations system (LMOS ”Lucent) that controls the metallic loop test (MLT ”Lucent) system. MLT measures the analog properties of the lines: resistance tip-ring, conductor-ground, line voltage, and loop capacitance . Line test systems gain access to the line via the metallic test trunk of a local digital switch (LDS) such as the 5ESS (Lucent), DMS-100 (Nortel), or EWSD (Siemens). Configuration consists of equipment preprovisioning and service provisioning. Equipment preprovisioning (aka "inventory creation") occurs when a network element is placed in the network and then entered into the inventory of network equipment that is ready for use. As a rule, information is entered during equipment preprovisioning whenever possible, so that minimizes the per-service-order effort. An OSS such as TMM (technology management module ”Telcordia) is used to enter new network elements into the SWITCH, LFACS, and TIRKS databases. Upon the receipt of a service order from a customer representative, the service provisioning (aka service activation) is performed to allocate equipment to the customer's service and to configure the equipment for the indicated type of service. Flow-through provisioning is a term used to describe service provisioning that requires no manual intervention issue work orders following the service order entry. The primary telephone network configuration operations system is TIRKS (trunk integrated record keeping system), developed by Telcordia. TIRKS keeps track of virtually all central office (CO) switching and transmission equipment, synchronous optical network (SONET) equipment, and HICAP circuits (including cable records for HICAPs). TIRKS interfaces with SWITCH (Telcordia) to manage GR303 interfaces to switches and main distributing frame (MDF) wire jumpers that connect outside line to CO equipment. Prior to SWITCH, MDF wire jumpers were managed by COSMOS (Telcordia). Recent change memory administration center (RCMAC) manages customer specific information in the local voice switch. TIRKSs also interfaces with LFACS (loop facilities assignment system ”Telcordia) to keep track of what subscriber lines are available and what line is associated with each customer service. DLESA (digital loop electronics service activation) adds capabilities to TIRKS, SWITCH, LFACS, and several OSSs to enable flow-through service provisioning for next generation digital loop carrier (NGDLC) systems. Traditional DLC (SLC-96, SLC-5, Fujitsu DLC) equipment and subtending subscriber loops are inventoried and assigned in LFACS. Network service database (NSDB ”Telcordia) provides unified access to the TIRKS database for systems, including OPS/INE and WFA. OPS/INE (Telcordia) generates TL1 messages to NGDLC equipment to configure the time slot assignments in the NGDLC. OPS/INE is being superceded by TEMS (transport element management system). WFA (work force administration ”Telcordia) generates work orders that inform technicians of the specific service provisioning and repair work that is needed and keeps track of the progress of the work. WFA (Telcordia) consists of WFA-C (controls the flow of orders), WFA-DI (dispatch-in to CO technicians), and WFA-DO (dispatch-out to outside plant technicians). The loop equipment inventory system (LEIS ”Telcordia) keeps track of equipment in the outside plant, including DLC. Customer service representatives use the service order retrieval and distribution systems (SORD) that forwards the service order to the service order activation and control (SOAC ”Telcordia) system interfaces with TIRKS to generate the service order and keep track of the completion of service provisioning. SOAC parses the service order and forwards the appropriate information to LFACS, SWITCH, and TIRKS. Accounting consists of service negotiation and billing. Bulk orders from major customers and carriers are entered into EXACT via electronic-bonded interfaces. Most customer service orders are entered by a telco service representative by a front-end service order entry system that feeds into SOAC. Customer billing is generated based on the universal service order code (USOC) and feature identifier (FID) combined with out-of-service records and automatic message accounting (AMA) records of feature usage and called number and call duration. Examples of billing systems include CABS (for carrier billing) and CRIS (for retail billing). Having reached this point, the reader should not be surprised to hear that even a simple feature addition can require millions of dollars and about two years for the necessary OSS development. |
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EAN: 2147483647
Pages: 154