|LQR, Link Quality Report|
|Type:||PPP link control protocol.|
In order to establish communications over a point-to-point link, each end of the PPP link must first send LCP packets to configure the data link during Link Establishment phase. During the Authentication and Network-Layer Protocol phases, the link may be tested to determine if quality is sufficient for operation. This testing is completely optional.
If an implementation desires that the peer use some specific link quality monitoring protocol, then it MUST negotiate the use of that protocol using the Quality-Protocol Configuration Option during Link Establishment phase.
The negotiation mechanism is independent in each direction. However, if the peer agrees to send Quality-Protocol packets, it MUST correctly process such packets on reception, even if it does not request such packets or implement a monitoring policy.
[RFC 1989] PPP Link Quality Monitoring.
[RFC 1333] PPP Link Quality Monitoring.