A system for supporting scalable bitmap based P_Key table in a high performance computing environment, comprising: one or more microprocessors; at least one subnet, the at least one subnet comprising one or more switches, the one or more switches comprising at least a leaf switch , wherein each of the one or more switches comprise a plurality of switch ports, a plurality of host channel adapters, each host channel adapter comprising at least one host channel adapter port, and a plurality of end nodes , wherein each of the plurality of end nodes are associated with at least one host channel adapter of the plurality of host channel adapters; wherein each of the plurality of end nodes are associated with at least one of a plurality of partitions; wherein each of the plurality of partitions are associated with a P_Key value; the system being characterized by a management entity adapted to determine and set a bitmap based P_Key table for each port of said plurality of switch ports and each host channel adapter port of said plurality of host channel adapter ports, wherein in said bitmap based P_Key table a representation of a P_Key value is a single bit, defining whether a packet including a P_Key value is allowed to pass through the switch port or the host channel adapter port performing a partition check for that port; wherein a switch port of the plurality of switch ports is associated with a bitmap based P_Key table of a plurality of bitmap based P_key tables (1201-1208) set by the management entity; and wherein a host channel adapter port of the plurality of host channel adapter ports is associated with a bitmap based P_Key table of the plurality of bitmap based P_key tables (1201-1208) set by the management entity. one or more microprocessors; at least one subnet, the at least one subnet comprising one or more switches, the one or more switches comprising at least a leaf switch , wherein each of the one or more switches comprise a plurality of switch ports, a plurality of host channel adapters, each host channel adapter comprising at least one host channel adapter port, and a plurality of end nodes , wherein each of the plurality of end nodes are associated with at least one host channel adapter of the plurality of host channel adapters; one or more switches, the one or more switches comprising at least a leaf switch , wherein each of the one or more switches comprise a plurality of switch ports, a plurality of host channel adapters, each host channel adapter comprising at least one host channel adapter port, and a plurality of end nodes , wherein each of the plurality of end nodes are associated with at least one host channel adapter of the plurality of host channel adapters; wherein each of the plurality of end nodes are associated with at least one of a plurality of partitions; wherein each of the plurality of partitions are associated with a P_Key value; the system being characterized by a management entity adapted to determine and set a bitmap based P_Key table for each port of said plurality of switch ports and each host channel adapter port of said plurality of host channel adapter ports, wherein in said bitmap based P_Key table a representation of a P_Key value is a single bit, defining whether a packet including a P_Key value is allowed to pass through the switch port or the host channel adapter port performing a partition check for that port; wherein a switch port of the plurality of switch ports is associated with a bitmap based P_Key table of a plurality of bitmap based P_key tables (1201-1208) set by the management entity; and wherein a host channel adapter port of the plurality of host channel adapter ports is associated with a bitmap based P_Key table of the plurality of bitmap based P_key tables (1201-1208) set by the management entity. <EOS>