This read-only OCTET STRING reports the calling party number for this leaf, applicable if this leaf is an SVC (switched, not permanent, virtual circuit), i.e., the address/number that originated the call establishing this leaf's connection. This is signaling-derived identification information useful for tracing which device or endpoint dialed in to create this particular dynamically-established leaf. An engineer auditing which remote sites are dynamically dialing into a multipoint SVC tree would inspect cktLeafSvcCallingParty for each leaf to identify the originating endpoints.