This attribute specifies the tolerable cell loss ratio (CLR) for rt- VBR traffic except for connections managed by a Vpt CA. The number is the negative logarithm (base 10) of the CLR. For example, if the target CLR = 1E-10 then RtVbr cellLossRatio = 10. This number must be the same as the Cbr cellLossRatio since CBR and rt-VBR traffic have the same discard priority. The RtVbr cellLossRatio is used by the Connection Admission Control (CAC) algorithm to compute the required (equivalent) cell rate for rt-VBR connections. This number must be less than or equal to the NrtVbr cellLossRatio, since rt-VBR traffic has a higher discard priority.

There is a trade-off between the service category CLR and the achievable link utilization. To guarantee an excellent service category, the CLR should be as small as possible (e.g., 1E-10). However, a smaller CLR results in a larger equivalent cell rate for a given connection and hence a lower link utilization.

Setting this attribute to 0 means that a CLR of 1 can be tolerated. In this case, no bandwidth is reserved for rt-VBR connections, and CAC is effectively turned off. All rt-VBR are admitted.