Frequent communication can indicate that commands are preparing an operation. Repeated short messages going back and forth are interpreted as negotiation between the commands involved. An abrupt end to that exchange can suggest that they have agreed a plan and action is approaching. Message routing can also reveal a chain of command and the units connected to it. These are inferences from communication patterns that remain useful when the message content cannot be decrypted.
Chapter · 1:37:43-1:38:50
Traffic patterns can reveal planning and command relationships
Message frequency, short exchanges and routing can expose operational preparation and command relationships before a code is broken.