ISO 11783/SAE J1939 Network Layer Lecture 6 Network Layer ISO Part 4, J BAE Spring 2009 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University Feb 16, 20091BAE

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 Feb 9, 20092BAE

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 protocol to different protocols (eg. Ethernet) Feb 9, 2009BAE

ISO System Feb 9, 2009BAE

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 Feb 9, 2009BAE

Filter Database Management Feb 9, 2009BAE CommandPGNCommand Byte Data N.MFDB_Request606720Port_Pair N.MFDB_Response606721Port_Pair, Filter Mode, [PGN List] N.MFDB_Add606722Port_Pair, [PGN List] N.MFDB_Delete606723Port_Pair, [PGN List] N.MFDB_Clear606724Port_Pair N.MFDB_Set_Mode606725Port_Pair, Filter Mode N.MFDB_Create_Entry606726Port_Pair, Filter Mode, [PGN List] Port Number Definitions NumberDefinition 0 Local 1-14 Assignable 15 Global (All ports) Filter Mode Definitions ModeDefintion 0 Block specified PGNs (Default = pass all) 1 Pass specified PGNs (Default = block all) reserved Defined by ISO Part 7 or J Message sent by transport protocol if needed

Access and Reset Parameterics FunctionPGN Control ByteOther Data field N.GP_Request (80h) Parameter Numbers N.GP_Response (81h) Parameter Values N.GP_Reset_Statistics (82h) Feb 9, 2009BAE FunctionPGN Control ByteOther Data field N.SP_Request (83h)Port-Pair, Parameter Numbers N.SP_Response (84h) Port-Pair, Parameter Values N.SP_Reset_Statistics (85h)Port-Pair General Port Specific

Access and Reset Parametrics: Parameters Resetable Parameter Number Number of BytesParameter values 0naUsed to request all parameters in numerical order 12 Buffer Size (bytes) 22 Max. Filter Database Size (bytes) 32 Number of Filter Database Entries 42 Max. Messages Received per second 52 Max. Messages Forwarded per second 62 Max. Messages Filtered per second 72 Max. Transit Delay Time (milliseconds) *82 Average Transit Delay Time (milliseconds) *92 # Messages lost due to Buffer Overflow *102 # Messages with Excess Transit Delay Time *112 Average Messages Received per second *122 Average Messages Forwarded per second *132 Average Messages Filtered per second 144 Uptime since last power on reset (seconds) 151 Number of Ports 16 – 253 na Reserved for future assignment by SAE 254 – 255 na See J for definitions Feb 9, 2009BAE Parameters:

Topology Query FunctionPGN Control ByteOther Data Field N.NT_Request (40h) Port_Pair N.NT_Response (41h) Port_Pair, SA List Provision to allow network topology to be determined