This represents the bandwidth for detour LSPs of this tunnel, expressed in thousands of bits per second. Setting it lower than the primary tunnel's own bandwidth -- a common practice to conserve backup capacity network-wide -- means traffic quality during a failover may degrade compared to normal operation since the detour is deliberately under-provisioned relative to the primary. For example, a primary tunnel carrying 100000 (100 Mbps) might have its detour's cmplsFrrConstBandwidth set to only 50000 (50 Mbps), accepting some congestion risk during a failover in exchange for not permanently reserving full backup capacity everywhere.