EFM Common MIB Issues

Common MIB or OAM MIB? “Common” MIB currently covers OAM Does not have anything common between EFM subjects –OAM, EoCu, and EPON Can we just make this EFM OAM MIB? –Wouldn’t affect MIB (nothing common anyway) –Would affect overview and introduction sections as they’re would be targeted differently

Loopback (I) EFM OAM Loopback is controlled via the states of two attributes at the local and peer OAM layer –Multiplexer (whether higher layer traffic is passed down) –Parser (identifies OAM traffic, and forwards or loops back other traffic) We have the choice to expose these primitives, or to go with something simpler and more abstract

Loopback (II) Simpler more abstract approach –Replace parser/multiplexer state with loopback status –dot3OamLoopbackStatus incorporates four state variables Local multiplexer state Local parser state Peer multiplexer state Peer parser state

Loopback (III) (From sent to exploder with details) Dot3OamLoopbackEntry ::= SEQUENCE { dot3OamLoopbackCommand INTEGER, dot3OamLoopbackStatus INTEGER } dot3OamLoopbackStatus OBJECT-TYPE SYNTAX INTEGER { noLoopback (1), initiatingLoopback (2), remoteLoopback (3), terminatingLoopback (4), localLoopback (5), unknown (6) }

Loopback (IV) How to map parser/multiplexer variables to loopback status: –The values of this attribute correspond to the following values of the local and remote parser and multiplexer states, where 'X' means the state can be any value. value LclPrsr LclMux RmtPrsr RmtMux noLoopback FWD FWD FWD FWD initLoopback DISCARD DISCARD FWD FWD rmtLoopback DISCARD FWD LPBK DISCARD tmtngLoopback DISCARD DISCARD LPBK DISCARD lclLoopback LPBK DISCARD DISCARD FWD unknown ** any other combination ** Pros: hides the complexity of the low-level service primitives (easier management) Cons: ???

Counters and Discontinuities Is guidance about counter discontinuities required or recommended? If so, is it acceptable to reference the ifCounterDiscontinuityTime as the key to whether discontinuities occurred, or do we need to create our own indication? E.g. is following text ok (for every counter)? Discontinuities of this counter can occur at re-initialization of the management system, and at other times as indicated by the value of the ifCounterDiscontinuityTime.

Event Counter Inconsistency (I) EFM OAM has defined events for things like frame error thresholds and symbol error thresholds EFM OAM events generally consist of –Timestamp: when did event happen –Window size: how big is the window (in time, in frames, whatever) –Threshold: how many things had to happen in that window to cause event –Count: how many things did happen in that window –Running total: how many things have happened since counters reinitialized?

Event Counter Inconsistency (II) Combining those two, EFM OAM events contains a running total of symbol errors –There is no C30 attribute for symbol errors, so this is a currently unexposed/uncounted variable The effect is –If events are being generated, one can access a counter of symbol errors –If no events are generated, cannot access symbol error counter Seems like a strange situation to the editor that a basic counter is exposed in the event that’s not in the MIB –This ok with everyone?

Event Controls (I) EFM OAM events are generated by the “OAM Client” EFM OAM events are received by the “OAM Client” EFM OAM treats the “OAM client” like a black box (e.g. doesn’t specify why it does things or when, only what it can do) Gives non management (e.g. our MIB) the freedom to introduce a set of controls on OAM client behavior What kind of controls are required for handling –When to generate events? –What to do if receive event from peer?

Event Controls (II) Options on when to generate include: –Just have on/off for events in general One big switch for entire event function –Have threshold controls but no on/off switch Can set thresholds high to basically disable event generation –Have on/off switch and thresholds for each event Separate event controls for most flexibility Options on what to do if receive include: –Store in table –Generate SNMP notification –Both

Event Controls (III) Proposing the following per-event attributes to control when “event” occurs: –Event Window size What is window of measurement –Threshold What is threshold in that window for event to occur Propose the following per-event controls for what to do when “event” occurs: –Event generation enable/disable Whether to generate EFM Event Notification OAMPDU if local event detected –Local SNMP notification enable/disable Whether to generate SNMP notification if local event detected –Remote SNMP notification enable/disable Whether to generate SNMP notification if remote event detected (e.g. receive EFM Event Notification OAMPDU from peer)