The field names used to represent message intervals are also expressed in terms of logarithms-so that in the standard, the message rate of an Announce message has the name logAnnounceInterval. This convention carries over into the operation of a PTP node, SO that on some implementations, an operator can configure the message rates on the clock only as log intervals rather than message rates. 7.3.1 Message Types and Flows PTP consists of two major types of messages. One type where the time is recorded at transmission, the message transported without delay, and then a timestamp recorded on reception (meaning the messages are time sensitive while in flight). These are known as event messages. Other messages that are not time sensitive are known as general messages and can carry data such as control, signaling, timestamps, and management information. Depending on the message type, both event and general messages may or may not carry accurate timestamps within them. Table 7-2 outlines the messages, which categories they fall into, and where they are covered in the IEEE 1588-2008 specification Table 7-2 PTP Message Types Event Messages General Messages Sync (13.6) Announce (13.5) Delay Req (13.6) Follow Up (13.7) Pdelay_ Req (13.9) Delay Resp (13.8) Pdelay Resp_Follow_Up(13.11) Pdelay_Resp (13.10) Signaling (13.12) Management (13.13 and 15) Some of the general messages (such as Follow_Up) may carry timestamp information but only as more of a reporting function-they do not need to traverse the network in the minimal time pos- sible, because their in-flight time is not being measured. On the other hand, the event messages are sensitive to delay while in transit because the duration of their in-flight time affects the time equa- tions on the slave. The message types beginning with "Pdelay" are specifically for the peer-to-peer (P2P) delay mech- anism (IEEE 1588-2008 section 11.4), and Delay_Req, and Delay_Resp messages are used for the end-to-end (E2E) delay response mechanism (1588-2008 section 11.3). These two approache