ISA100.11a Pengfei Ren pengfei@wayne.edu
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Introduction Wireless Instrumentation The merger of WSN technologies and industrial field instruments WirelessHART, ISA100.11a and WIA-PA Advantages: cost-efficient, scalability, flexibility, and mobility ISA100.11a Time: Oct, 2009 Goal: offer secure and robust wireless connectivity for industrial automation applications Application: noncritical monitoring and control applications
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
System Overview
System Overview Concepts device: the physical embodiment of the behaviors, configuration settings, and capabilities that are necessary to implement and operate a network. role: a collection of functions and capabilities. All ISA100.11a devices shall implement at least one role. Network Size Constraints Network latency and power consumption Choke points at the devices close to the backbone router Communication bandwidth Upper limit: 50-100
System Overview: roles
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Communication Protocol
Communication Protocol Physical Layer Function: transmission and reception of raw data packets, channel selection, CCA, energy detection. Channels: 2.4 GHz, 11-25 (26) Modulation: DSSS and O-QPSK 250 kbps Transmission Power: 10mW 100m with direct line of light Data Link Layer
Communication Protocol Data Link Layer Peer-to-Peer communication behavior: channel access, radio synchronization, and security control Message forwarding and routing within a subnetwork Graph and source routing
Communication Protocol Data Link Layer TDMA
Communication Protocol Data Link Layer Channel Hopping: slotted and slow hopping CSMA-CA (?for event traffic;?only used slow-frequencyhopping mode)
Communication Protocol Data Link Layer The duration of a slow hopping period is configurable. A slow hopping period is generally used to provide immediate, contention-based channel bandwidth on demand to a group of devices (mostly uses?) CSMA-CA in slowhopping patterns Slow hopping event-based and time critical traffic Slow hopping can decrease communication latency, but increase power consumption compared to slotted hopping (due to overhearing channels all the time). Hopping patterns
Communication Protocol Network Layer Routing beyond the DL subnet Fragment and reassemble data packets that exceed the maximum length allowed by the DLL Transport Layer End-to-End communication Connectionless service extending UDP over IPv6 optional compression Better data integrity checks, and additional authentication and encryption mechanisms
Communication Protocol Application Layer Provides services to user-defined application processes Upper AL (UAL) contains the application processes for a device Application sublayer (ASL) provides services need for the UAL
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Attacks
Security mechanisms Payload Encryption and Message Authentication Payload encryption, and single-hop and multi-hop message authentication Counter with cipher block chaining message authentication code (CCM) and Advanced encryption standard with 128-bit block size (AES-128) Security Keys Model Symmetric cryptography: join key (optional), master key, DL key (for data link layer), session key (for transport layer) Asymmetric cryptography: CA-root and Cert-A
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Coexistence
Coexistence Spectrum Management CCA Blacklisting
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Implementations and Equipment Field Devices
Implementations and Equipment Field Devices Value chain: IEEE 802.15.4 radio providers, ISA100.11a radio module providers, and ISA100.11a field device providers.
Implementations and Equipment System Manager and Wireless Gateway
Outline Introduction System Overview Communication Protocol Security Coexistence Implementations and Equipment Conclusion
Conclusion ISA100.11a Providing adequate network performance of noncritical monitoring applications Starting to address critical safety applications
Q&A