The ISA100 uses 802.15.4:2006 as Physical layer and the MAC functionality as access or intermediate layer before the DLL. ISA100 standard uses the PHY layer defined by the 802.15.4 and the mandatory functions of the MAC sub-layer (defined by the same 802.15.4). The ISA100 defines the communication stack starting with Data Link Layer (DLL) which also completes some of the functions of the 802.15.4 MAC; so the ISA100 is not only an Application Layer protocol. The same ISA100 DLL implements the TDMA functionality which was not tackled by the 2006 802.15.4 protocol.
Retransmission mechanisms can be found at Data Link Layer, Transport Layer and Application Layer of ISA100 protocol.
Phase 1 : Device provisioning.
Phase 2: Device join to the network(equivalently join to a Versa Router)
Phase 3: Contract establishment with Versa Router.
Publish Period : Number of seconds between two consecutive transmissions.
Publish Phase: Used for periodic communication; to identify the assigned phase (within the publishing period) of publications in the contract; valid value set: 0 to 99
By default a timeslot is set to 10ms. It ca be however configurable(for higher values). A complete interoperability is provided by the current standard for systems using different timeslots.