Subject: Telecom Network Management

Topic: Broadband Network Management

Difficulty: Medium

The ATM Forum Management Model:

i. The Network Management Working Group of the ATM Forum has developed an end-to-end generic management model that encompasses private and public networks and lays out standards for interworking between them.

ii. The model defines gateways between SNMP and CMIP systems, and between standards-based and proprietary systems. Five key management interfaces are defined in this model, labelled M1-M5.

iii. M1 is concerned with the management of the end-user equipment connecting to either private or public switches. M2 undertakes management of private ATM switches and networks. Private ATM network management is addressed through MI combined with M2. M4 deals with their public ATM switches and networks. M3 is the link between private and public networks, used for exchanging fault, performance and configuration information. Finally, M5 supports interactions between any two public networks. The definition of these interfaces allows a complete management service, ranging from a global view of the network (M5 management inter-face) to the management of individual elements (M1 management interface).

iv. In some cases, several management interfaces use the same information from a management information base (MIB) tree.

M1/M2 Interfaces and the ILMI Implementation:

i) The Interim Local Management Interface (ILMI), which is an implementation of the MI /M2 interfaces. ILMI enables the exchange of status, configuration, accounting and control information between any two ATM devices - such as two ATM switches - across a user-to-network inter-face (UNI).

ii) For ILMI to function, every ATM switch or network terminator and every ATM network that deploys a public or private network UNI must be equipped with a UNI Management Entity (UME) which supports an ILMI MIB. Two adjacent (or peer) UMEs can communicate using the common attributes provided by the ILMI.

iii) By sending SNMP commands, a UME may obtain or modify information contained in its ILMI MIB. The ILMI MIB is hierarchically organised (Table2). It contains information concerning each group listed in Table. Also defined are functions that allow retrieval and handling of information in the ILMI MIB.

iv) The ILMI has been deployed by some vendors to perform management tasks across the UNI for some devices. However, since the ILMI provides a solution that is applicable only at the UNI, it cannot support the management tasks that are involved in a network comprising a range of ATM devices. Thus, on its own, the ILMI does not provide the capability to manage multi-vendor ATM networks.

For more detail about M1, M2, M3, M4 and M5 interfaces refer Discuss M1, M2, M3, M4 and M5 interface in ATM network management. asked in May2016.

• Asynchronous transfer mode (ATM) is, according to the ATM Forum, a telecommunications concept defined by ANSI and ITU standards for carriage of a complete range of user traffic, including voice, data, and video signals.

• ATM was developed to meet the needs of the Broadband Integrated Services Digital Network and designed to unify telecommunication and computer networks.

• It was designed for a network that must handle both traditional high-throughput data traffic (e.g., file transfers), and real-time, low-latency content such as voice and video.

• The reference model for ATM approximately maps to the three lowest layers of the ISO-OSI reference model: network layer, data link layer, and physical layer.

• ATM is a core protocol used over the SONET/SDH backbone of the public switched telephone network (PSTN) and Integrated Services Digital Network (ISDN), but its use is declining in favour of all IP.

• ATM provides functionality that is similar to both circuit switching and packet switching networks

• ATM uses asynchronous time-division multiplexing and encodes data into small, fixed-sized packets (ISO-OSI frames) called cells.

• This differs from approaches such as the Internet Protocol or Ethernet that use variable sized packets and frames.

• ATM uses a connection-oriented model in which a virtual circuit must be established between two endpoints before the actual data exchange begins.

• These virtual circuits may be “permanent”, i.e. dedicated connections that are usually preconfigured by the service provider, or “switched”, i.e. set up on a percall basis using signalling and disconnected when the call is terminated.

• The Network Management Working Group of the ATM Forum has developed an end-to-end generic management model that encompasses private and public networks and lays out standards for interworking between them.

• The model defines gateways between SNMP and CMIP systems, and between standards-based and proprietary systems. Five key management interfaces are defined in this model, labelled M1-M5.

• Individually, a cell is processed asynchronously relative to other related cells and is queued before being multiplexed over the transmission path