Terminology for MPLS OAM

reverse

A direction opposite to the direction that traffic flows along the monitored service link.

forward

A direction that traffic flows along the monitored service link.

path merge LSR

An LSR that receives the traffic transmitted on the protection path in MPLS OAM protection switching.

If the path merge LSR is not the traffic destination, it sends and merges the traffic transmitted on the protection path onto the working path.

If the path merge LSR is the destination of traffic, it sends the traffic to the upper-layer protocol for handling.

path switch LSR

An LSR that switches or replicates traffic between the primary service link and the bypass service link.

user plane

A set of traffic forwarding components through which traffic flow passes. An OAM CV or FFD packet is periodically inserted to this traffic flow to monitor the forwarding component status. In IETF drafts, the user plane is also called the data plane.

Ingress

An LSR from which the forward LSP originates and at which the reverse LSP terminates.

Egress

An LSR at which the forward LSP terminates and from which the reverse LSP originates.

BDI

Backward Defect Indication

CV

Connectivity Verification

FDI

Forward Defect Indication

FFD

Fast Failure Detection

MPLS

Multiprotocol Label Switching

TTSI

Trail Termination Source Identifier

DM

Delay Measurement

LM

Loss Measurement

OAM

Operation, Administration and Maintenance

PE

Provider Edge Router

SD

Signal Deterioration

SF

Signal Failure