a distribution node such as node 200 7 the function performed by a routing node is different than a distribution node since a routing node is responsive to the most significant bit of the trunk destination control field to determine which output control the packet is to be routed to for example if node 200 7 was receiving the disable signal via conductor 1112 it would perform the following routing node functions input control 1101 would be responsive to a packet received on link 213 to route this packet to output control 1102 if the most significant bit of the trunk destination control field was a 34 0 34 or to route this packet to output control 1103 if the most significant bit of the trunk destination control field was a 34 1 34 during the transfer of the packet from input control 1101 to the designated output control input control 1101 left shifts the most significant bit of the trunk destination control field to the least significant bit position this left shift operation assures that the trunk destination control field is in the proper state so that the next routing node can base its routing decision on the most significant bit of the trunk destination control field when a node is performing.