Industrial Internet Connectivity Framework | Page 15

Connectivity Framework

2 : Connectivity Framework

The lowest layer is the physical layer , which refers to the exchange of physical signals ( electric , optical , or other ) on the physical media ( wired or wireless ) connecting the participants . Above it is the link layer , which refers to the exchange of frames using signaling protocols on the shared physical link between adjacent participants . Above it is the network layer , which refers to the exchange of packets ( bounded length ), possibly routing them over multiple links to communicate between non-adjacent ( remote ) participants . Above it is the transport layer , which refers to the exchange of messages ( variable length ) between participant applications . Above it is the framework layer , which refers to the exchange of structured data ( state , events , streams ) with configurable quality-of-service between participant applications . Above it , but outside the scope of connectivity , is the distributed data interoperability and management layer crosscutting function that relies on the data sharing mechanism provided by the connectivity framework layer .

The Internet Protocol ( IP ) ( Wikipedia ) 1 is the prevailing network layer connectivity standard that has given birth to the internet and now IIoT . The IP network layer has enabled independent innovation , both below and above the network layer . The bottom three layers , common to the OSI model and the Internet model , have been in use longer and are generally understood ; although evolution of IP and non-IP connections and the multitude of wireless-access technologies coming to market create new choices for the IIoT community .

Figure 2-2 : The focus of this document is on connectivity layers above the network layer , namely the connectivity transport and the connectivity framework layers .

1

See [ IETF-RFC1122 ], for overview [ WKPD-IPS ] IIC : PUB : G5 : V1.0 : PB : 20170228 - 15 -