Nortel Networks 3500, NTRN10AN manual Telemetry byte-oriented serial Tbos, Single-ended Tbos

Operation, administration, and maintenance (OAM) features 2-59

Telemetry byte-oriented serial (TBOS)

The OPTera Metro 3500 network element is equipped with a telemetry byte-oriented serial (TBOS) subsystem that facilitates display of alarms at remote network elements. The TBOS subsystem determines the location of the network element that triggered the alarm.

When a remote alarm is detected by the TBOS system, the remote LED illuminates at the network element defined as the TBOS head-end.

When the network element that has raised the alarm is identified, you can log in to that network element and identify the fault details.

The OPTera Metro 3500 network element supports TBOS monitoring through a dedicated TBOS port and a subset of TBOS information through the Site Manager. OPTera Metro 3500 supports TBOS through a four-wire, half duplex, 2400 baud, RS-422 port on the Left OAM (LOAM). Remote telemetry can be performed using the TBOS port and an E2A monitor. A TBOS status matrix can also be displayed using the Site Manager interface.

TBOS data is transmitted using 8 bytes containing 4 bits of data each. These 32-bit displays represent alarm conditions on a network element.

The TBOS standard states the following:

•There must be 64 bits assigned to represent alarm conditions on a network element.

•There must be a total of eight such displays.

Single-ended TBOS

The OPTera Metro 3500 allows a single TBOS link to monitor several interconnected network elements such as those in a UPSR or in a linear system. (A linear system has no limit on chain size. However, the head-end only monitors 16 network elements from the head-end.) The monitored network elements are in what is called a monitored span. Network elements in the monitored span communicate their alarm status to each other. This communication allows TBOS to obtain alarm information about all the other network elements in the monitored span.

TBOS mapping assignments are set up at one network element in each monitored span. This network element is called the TBOS head end. Any node can be selected as the head-end network element.

Protocol problems occur if more than one network element is configured as a TBOS head end. If a second head end is set up, the TBOS remote flag becomes erroneous.

Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004