It is mandatory for every eHBL transmission to reference the marine carrier’s Primary CCN, while every Close Message must reference the Previous CCN above it, which is the co-loader’s 8000 CCN. In a co-load situation, every freight forwarder, regardless of the number of tiers, must quote the carrier’s Primary CCN in its eHBL data. Co-loaders must communicate quickly and efficiently to ensure the Primary CCN is shared with every freight forwarder in the consolidation. Furthermore, every Close Message must reference the freight forwarder’s 8000 Previous CCN above it.