Y.1731 MIB Support

ExtremeXOS 15.5 supports Y.1731 performance measurement MIB defined by MEF - 36. The performance monitoring process is made up of a number of performance monitoring instances, known as performance monitoring (PM) sessions. A PM session can be initiated between two MEPs in a MEG and be defined as either a loss measurement (LM) session or delay measurement (DM) session. The LM session can be used to determine the performance metrics frame loss ratio, availability, and resiliency. The DM session can be used to determine the performance metrics Frame Delay.

The MIB is divided into a number of different object groupings: the PM MIB MEP objects, PM MIB loss measurement objects, PM MIB delay measurement objects, and SOAM PM notifications. The initial implementation of MIB supports GET operations for Frame Loss& Frame Delay.

MIB Specific Data

• A measurement interval of 15 min to be supported
• Default message period/transmit-interval of LMMs is 1 sec (Min = 1sec in current CLI) * Default message period/transmit-interval of DMMs is 100msec (Min = 1 sec in current CLI)
• Repetition Time can be set to 0 which means that there is no gap between measurement intervals
• Number of History measurement intervals can be 2-1000, though it expects at least 32 measurement intervals to be stored and 96 are recommended.
• Both DM and LM sessions are MEP to MEP sessions. The index of all the DM/LM tables includes MD, MA, MEP table indices as well as the particular DM/LM session.
• Currently DM sessions are not MEP-to MEP based but only segment based sessions. To support DM tables in the MIB, changes are required in the current CLI & backend delay implementation.

Limitations

• Currently we are storing a maximum of 1800 frames data for each LMM/DMM session. But to support at least 2 history and 1 current measurement intervals, we need to store 2700 frames (if message period is 1 sec, Repetition time is 0, measurement interval is 15 min) for each delay/loss session.
• Each frame‘s data is about 60 bytes for LMM and which takes about 44 MB of memory for 288 sessions