hdlcMonitorIndex 1.3.6.1.4.1.343.6.30.1.1.1.1

The IfIndex for the layer that these counters apply to. The index may belong to the encapsulation layer (e.g. PPP), an individual B-channel (ISDN), a B-channel Bundle (ISDN) or the HDLC layer of a V.x WAN link.