An illustrative example network monitoring device performs a lossless byte level compression of time series data communicated over the network. The device includes a processor configured to monitor a plurality of communications over the network. For each communication, the device determines whether a message included in the communication was included in a previous communication. When the message was not included in a previous communication, the processor associates a message identifier with the communication, associates a time indicator with the communication, and stores information regarding content of the communication. When the message was included in a previous communication, the device determines a difference in time between the communication and the previous communication and determines any content difference between content of the communication and content of the previous communication. The device stores information for the communication including a time difference indicator and information regarding only the determined content difference.