9.9 SNMP for Management

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Managed CSU-DSUs generally offer SNMP management support and/or IP telnet. To carry the management data, they require an Ethernet interface, the FDL bits available on ESF links, or a frame relay PVC. With this approach, management data is inserted on a private data link connection identifier (DLCI) between a local router and the remote device or on a WAN PVC dedicated to management. Management data can even use a PVC that usually carries user data. When there is no user data on that PVC, it is made available to carry management information.

SNMP can provide a variety of performance information to a centralized console, including physical-link errors and frame counts. Alarms in the network can be passed up to an SNMP console via traps, and often trap thresholds may be set. But SNMP is not good for collecting long-term statistics for trending and service-level management. SNMP is also poor for providing higher-layer protocol data. Frequent polling of the device to collect management data is impractical, and many information elements are not captured via SNMP.

An increasingly popular management option is the use of the Web browser as the user interface. When an administrator points a browser at the device’s IP address, a graphical configuration, status, and diagnostics display are presented that are more intuitive than the typical command-line text-based interface. Alerts from the unit can be issued to an administrator via e-mail.

Custom device-configuration applications are available that run on Windows- or-UNIX-based computers. These systems provide graphical configuration, monitoring, and management of the CSU-DSU and can be used to create configurations offline or update software over the network.

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