802.3ah OAM Event Notification (`efm_oam_event_notification`)

Layer: L2 (data link)
Header: variable length
Notes: PTP / ESMC / CFM / R-APS / 802.3ah OAM (P2)

Reached from

Lower layer	Selector	Value
`ethernet2`	First 8 bits of the payload when `ethertype` = 34825 (0x8809)	3 (0x03)
`efm_oam`	`code`	1 (0x01) (re-decodes this layer)

Fields

Field	Type	Default	Auto	Description
`subtype`	`uint(8)`	`3`		Slow Protocols subtype (3 = OAM).
`flags`	`flags(16)`	`0x50`		Flags: link fault, dying gasp, critical event, local / remote evaluating and stable.
`code`	`enum(8)`	`1` (event_notification)		OAMPDU code: 0x00 Information, 0x01 Event Notification, 0x02 Variable Request, 0x03 Variable Response, 0x04 Loopback Control, 0xfe Organization Specific.
`sequence_number`	`uint(16)`	`1`		Event notification sequence number.
`tlvs`	`tlv` — up to and including the first item of type 0, or the end of the PDU	2 items		Link event TLVs (8-bit type, 8-bit length including the header, Auto): errored symbol period, errored frame, errored frame period, errored frame seconds summary, Organization Specific, closed by the End TLV (type 0).

`flags`

Bit	Mask	Name
0	1 (0x0001)	`link_fault`
1	2 (0x0002)	`dying_gasp`
2	4 (0x0004)	`critical_event`
3	8 (0x0008)	`local_evaluating`
4	16 (0x0010)	`local_stable`
5	32 (0x0020)	`remote_evaluating`
6	64 (0x0040)	`remote_stable`

`code`

Value	Name
0 (0x00)	`information`
1 (0x01)	`event_notification`
2 (0x02)	`variable_request`
3 (0x03)	`variable_response`
4 (0x04)	`loopback_control`
254 (0xfe)	`organization_specific`

`tlvs`

Type 8 bits, length 8 bits.
The length counts the type and length fields too.
Unknown types are kept as raw value octets.

Type	Name	Value fields	Description
0 (0x00)	`end`	(type only, no length or value)
1 (0x01)	`errored_symbol_period`	`timestamp`, `window`, `threshold`, `errors`, `error_running_total`, `event_running_total`
2 (0x02)	`errored_frame`	`timestamp`, `window`, `threshold`, `errors`, `error_running_total`, `event_running_total`
3 (0x03)	`errored_frame_period`	`timestamp`, `window`, `threshold`, `errors`, `error_running_total`, `event_running_total`
4 (0x04)	`errored_frame_seconds_summary`	`timestamp`, `window`, `threshold`, `errors`, `error_running_total`, `event_running_total`
254 (0xfe)	`organization_specific`	`oui`, `value`

`tlvs` › `errored_symbol_period`

Field	Type	Default	Auto	Description
`timestamp`	`uint(16)`	`0`
`window`	`uint(64)`	`10`
`threshold`	`uint(64)`	`1`
`errors`	`uint(64)`	`1`
`error_running_total`	`uint(64)`	`1`
`event_running_total`	`uint(32)`	`1`

`tlvs` › `errored_frame`

Field	Type	Default	Auto	Description
`timestamp`	`uint(16)`	`0`
`window`	`uint(16)`	`10`
`threshold`	`uint(32)`	`1`
`errors`	`uint(32)`	`1`
`error_running_total`	`uint(64)`	`1`
`event_running_total`	`uint(32)`	`1`

`tlvs` › `errored_frame_period`

Field	Type	Default	Auto	Description
`timestamp`	`uint(16)`	`0`
`window`	`uint(32)`	`10`
`threshold`	`uint(32)`	`1`
`errors`	`uint(32)`	`1`
`error_running_total`	`uint(64)`	`1`
`event_running_total`	`uint(32)`	`1`

`tlvs` › `errored_frame_seconds_summary`

Field	Type	Default	Auto	Description
`timestamp`	`uint(16)`	`0`
`window`	`uint(16)`	`10`
`threshold`	`uint(16)`	`1`
`errors`	`uint(16)`	`1`
`error_running_total`	`uint(32)`	`1`
`event_running_total`	`uint(32)`	`1`

`tlvs` › `organization_specific`

Field	Type	Default	Auto	Description
`oui`	`uint(24)`
`value`	`bytes` — rest of the PDU

Sample templates

efm-oam-event — templates/protocols/oam/efm-oam-event.wpg.yaml