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ISO 11783/SAE J1939 Network Layer. Lecture 6 Network Layer ISO 11783 Part 4, J1939-31 BAE 5030 - 353 Spring 2009 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University. Purpose of Network Layer. Defines functionality of network interconnection units
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ISO 11783/SAE J1939 Network Layer Lecture 6 Network Layer ISO 11783 Part 4, J1939-31 BAE 5030 - 353 Spring 2009 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University BAE 5030-353
Purpose of Network Layer • Defines functionality of network interconnection units • Segment to segment communication • Network Interconnection Unit tasks • Transfer of messages between segments • Forwarding • Filtering • Address translation • Re-packaging • Performance statistics BAE 5030-353
Network Interconnection Unit types • Repeater • Bit level repeating from one segment to another (physical layer) • Adds to effective bus length (propagation delay) • Bridge • Receives, stores and forwards messages from one segment to another (data link layer) • May filter messages • Maximum recommended transit delay is 50 ms • Router • May re-map addresses of messages from one segment to another (network layer) • Does not allow address claims to pass across • Gateway • Interconnects ISO 11783 protocol to different protocols (eg. Ethernet) BAE 5030-353
ISO 11783 System BAE 5030-353
Network Port Identification • Port Numbering • Each port on a network interconnection device is numbered for reference. These are standardized in Parts 1 and/or in 4 and 9
Network Layer Message • Purpose • Acquiring NIU performance statistics • Setup and management of filter databases • Control Byte Functions • Filter Database Management ( 7 functions) • Setup filtering between port-pairs • Access and Reset General and Parametrics ( 3 Functions) • Access or reset general NIU performance data • Access and Reset Port-Pair Parametrics ( 3 Functions) • Access or reset port-pair specific NIU performance data • Topology query (2 functions) • Access Network Topology BAE 5030-353
Filter Database Management Message sent by transport protocol if needed BAE 5030-353
Access and Reset Parameterics General Port Specific BAE 5030-353
Access and Reset Parametrics: Parameters Parameters: BAE 5030-353
Topology Query Provision to allow network topology to be determined