Figure 99 2 provides a functional block diagram of the MAC Merge sublayer.

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1 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December Proposed changes to add verification to Clause :.. Functional Block Diagram Figure provides a functional block diagram of the MAC Merge sublayer. emac PLS service interface MMSI emac:pls_data.indication emac:pls_data_valid.indication emac:pls_signal.indication emac:pls_data.request emac:pls_carrier.indication pmac PLS service interface pmac:pls_data.indication pmac:pls_data_valid.indication pmac:pls_signal.indication pmac:pls_data.request pmac:pls_carrier.indication MM_CTL.request.. Start mframe Delimiter (SMD) Express Filter Receive Processing Verification Transmit Processing Figure MAC Merge Functional Block Diagram Reconciliation sublayer PLS service interface RS:PLS_DATA.indication RS:PLS_DATA_VALID.indication RS:PLS_SIGNAL.indication RS:PLS_DATA.request RS:PLS_CARRIER.indication The value of the SMD indicates whether the mframe contains an express frame, the start of a preemptable frame or a non-initial fragment of a preemptable frame. An mframe containing the start of a preemptable frame contains the whole frame if the frame is not preempted. 0 Copyright IEEE. All rights reserved.

2 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December For mframes carrying all or part of a preemptable frame, the SMD also indicates the frame count. The frame count prevents reassembling an invalid frame if the final mframe of one preemptable frame and the initial fragment of the next preemptable frame are lost. The frame count is a modulo- count. Two additional SMD values, SMD-V and SMD-R, identify a mframes used to verify that a link can support preemption capability. The SMD values are specified in Table. mframe type The notation SMD-S is used to refer to any of the four SMD values in the initial mframe of a preemptable frame. The notation SMD-C is used to refer to any of the four SMD values in a non-initial mframe... Verifying preemption operation Table SMD values Notation Frame count verify frame SMD-V 0x0 respond frame SMD-R 0x express frame SMD-E 0xD preemptable frame start SMD-S0 0 0xE SMD-S 0xC SMD-S 0xF Encoding SMD-S 0xB non-initial fragment SMD-C0 0 0x SMD-C 0x SMD-C 0xE SMD-C 0xAD There are proprietary devices that forward a frame with the Nearest Bridge group address (e.g. media converters or switches that don t comply with IEEE 0.Q). How such a device will handle an mframe of a preemptable frame is indeterminate. A proprietary device might forward the mframe unchanged, alter the mframe (e.g. insert an SFD), or drop the mframe. Verification checks that the the link can support preemption capability. Preemption capability shall be active only if the capability has been enabled and verified. If preemption capability is enabled and has not been verified, MAC Merge initiates transmission of a verify mframe. A verify mframe has octets of preamble,(0x) an SMD-V, 0 octets of 0x00 and an MCRC. 0 Copyright IEEE. All rights reserved.

3 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December Transmission of a verify frame may be repeated to allow verification in the presence of noise causing bit errors. When an mframe with an SMD-V and a correct MCRC is received, a response mframe is sent. A response frame has octets of preamble (0x), an SMD-R, 0 octets of 0x00 and an MCRC. When an mframe with an SMD-R and a correct MCRC is received, preemption capability is verified. [Editor s note (to be removed prior to publication) - this is the most conservative verification alternative. The MAC Merge sublayer only checks for a response when it has sent a verify frame and each side must initiate verification before enabling preemption. Another alternative would be to set verified in response to receivign a verifiy mframe in addition to when receiving a response mframe. Therefore, after enabling preemption, a preemptable frame that requires a response from the link partner should be sent to verify preemption operation. If no response is received preemption should be disabled. [Editior s note (to be removed prior to publication) - Further work is needed in this area. Some proprietary devices may convert the SMD to an SFD. For a preemptable frame that was not preempted, this converts the frame to an express frame which will be received and processed by the link partner. To detect that such a device is in the path requires that the response only be generated if the frame is received on the preemptable path. Possibly a MAC Control frame should be defined for this. Also the test frame should be repeated at least once in case the test or response was lost due to a bit error.].. Detailed functions and state diagrams Change and add constants, variables, functions and counters are shown.... Constants verifylimit the integer, the number of verification attempts... Variables link_fail Boolean variable that is set TRUE by implementation dependent means when a link failure is detected. pactive Boolean variable that is TRUE when preemption capability is active and FALSE otherwise. The value of pactive is penable verified. penable Boolean variable that is TRUE when preemption capability is enabled and FALSE otherwise. rcv_r Boolean that is set TRUE when an mframe with SMD-R and a correct mcrc is received. rcv_v Boolean that is set TRUE when an mframe with SMD-V and a correct mcrc is received. send_r Boolean that is set TRUE to initiate sending a response mframe. send_v Boolean that is set TRUE to initiate sending a verification mframe. verified Boolean that is set TRUE when the ability of the link to support preemption capability has been verified.. 0 Copyright IEEE. All rights reserved.

4 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December verify_fail Boolean that is set TRUE when verification attempts have failed.... Functions SMD_DECODE Decodes the value of mpls_data.indication primitives returning one of the following values based on the value of the primitives: Preamble 0x E SMD-E encoding S SMD-S encoding C SMD-C encoding V SMD-V encoding R SMD-R encoding Error Any other value. If S is returned, the function sets rxframecnt equal to the frame count indicated by the SMD-S. If C is returned, the function sets cframecnt equal to the frame count indicated by the SMD-C. TX_R Produces mpls_data.requests to send a response mframe: octets of 0x, octet SMD-R, 0 octets of 0x00, mcrc followed by an mpls_data.request with the value DATA_COMPLETE. TX_V Produces mpls_data.requests to send a verify mframe: octets of 0x, octet SMD-V, 0 octets of 0x00, mcrc followed by an mpls_data.request with the value DATA_COMPLETE.... Counters verifycnt a count of the number of verification tries that have completed.... Timers verify_timer A timer of time from when a verification mframe was sent to initiating the next attempt. The timer will set verify_timer_done when it reaches ms ± %. response_timer A timer for determining when verification has failed. The timer will set response_timer_done when it reaches 0 ms ± % 0 Copyright IEEE. All rights reserved.

5 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December... State diagrams The Transmit Processing State Diagram is shown in Figure Figure. The Receive Processing State begin B B etx=true ipg_timer=dne EXPRESS TX mtx_data(etx_data) etxcplt=true E TX COMPLETE mtx_cplt etxcplt FALSE resumetx=false etx=true ipg_time=done INIT TX PROC txframecnt 0 IDLE TX PROC fragsize 0 txfrag 0 start ipg_imer etxcplt FALSE send_r=false send_v=true ipg_imer=done etx=false TX VERIFY TX_V send_v FALSE etxcplt=false resumetx=true RESUME WAIT start ipg_timer preamblecnt 0 ipg_timer=done hold=false RESUME PREAMBLE mtx_data(0x) preamblecnt ++ preamblecnt preamblecnt = SEND SMD-C SMDC_ENCODE(txFrame) fragsize 0 SEND FRAG COUNT SMDC_ENCODE(txFrag) txfrag++ A START PREAMBLE mtx_data(ptx_data) SFD_DET=FALSE SEND SMD-S Figure Transmit Processing State Diagram C TX RESPOND TX_R send_r FALSE ptx=true etx=false ipg_timer= done hold=false send_v=fale end_r=false SMDS_ENCODE(txFrame) A preempt=true SFD_DET=TRUE PREMPTABLE TX mtx_data(ptx_data) fragsize++ TX MCRC TX_MCRC C send_r=true ipg_timer=done etx=false mtx_cplt preempt=true P TX COMPLETE PREMPT WAIT start ipg_timer resumetx TRUE ipg_timer=done ptxcplt=false preempt=false ptxcplt=true ptxcplt=true 0 Copyright IEEE. All rights reserved.

6 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December Diagram is shown in Figure. The Express Filter State Diagram is shown in Figure. The Verify 0 Copyright IEEE. All rights reserved.

7 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December preamble RX PREAMBLE prx_data(0x) REPLACE SMD prx_data(0xd) mrxdv=true RX_MCRC_CK=FALSE begin IDLE RX PROC ResumeRx FALSE nxtrxfrag 0 mrxdv=true pmac DATA VALID prx_dv(true) CHECK FOR START SMD_DECODE(mRX_DATA) S C OTHER RECEIVE DATA prx_data(mrx_data) RX_MCRC_CK=TRUE preamble rxfragcnt=nxtrxfrag INCREMENT FRAG CNT rxfragcnt=++ INIT RX PROC mrxdv=false E WAIT FOR DV FALSE WAIT FOR RESUME mrxdv=true CHECK FOR RESUME SMD_DECODE(mRX_DATA) C CHECK CHECK FRAG CNT FRAG_DECODE(mRX_DATA) BAD FRAG prx_dv(false) Figure Receive Processing State Diagram V RCV V E rxfragcnt nxtrxfrag R RX_MCRC_CK=TRUE RCV R V MCRC OK R MCRC OK rcv_v TRUE rcv_r TRUE EXPRESS prx_dv(false) FRAME COMPLETE prx_dv(false) ASSEMBLY ERROR DISCARD RX_MCRC_CK=TRUE 0 Copyright IEEE. All rights reserved.

8 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December begin INIT EXPRESS FILTER EXPRESS FILTER IDLE erx_dv(false) mrxdv=true emac RECEIVE DATA VALID erx_dv(true) CHECK FOR EXPRESS SMD_DECODE(mRX_DATA) preamble EXPRESS PREAMBLE S C Other E NOT EXPRESS erx_data(0x) SFD erx_data(0xd) erx_dv(false) E RECEIVE DATA erx_data(mrx_data) mrxdv=true Figure Express Filter State Diagram 0 Copyright IEEE. All rights reserved.

9 Draft Amendment to IEEE Std 0.- IEEE Draft P0.br/D.0 IEEE 0.br Task Force name Task Force December State Diagram is shown in Figure. begin link_fail INIT VERIFICATION send_v FALSE verified FALSE rcv_v FALSE verify_fail FALSE send_r FALSE verifycnt 0 rcv_r FALSE VERIFICATION IDLE SEND VERIFY send_v TRUE penable = TRUE WAIT FOR RESPONSE start verify_timer tart response_timer erfycnt ++ verify_timer_done rcv_r = FALSE verifycnt verifylimit rcv_r = TRUE VERIFIED verified TRUE send_v = FALSE response_timer_done rcv_r = FALSE verifycnt verifylimit VERIFY FAIL verify_fail TRUE Figure Verify State Diagram begin rcv_v = TRUE RESPOND IDLE SEND RESPOND rcv_v FALSE send_r TRUE send_r = FALSE 0 Copyright IEEE. All rights reserved.

SMD-S ENCODING NOVEMBER 2015 TOBIAS BELITZ AUTOMOTIVE NETWORK COMMUNICATION PROTOCOL RENESAS ELECTRONICS CORPORATION

SMD-S ENCODING NOVEMBER 2015 TOBIAS BELITZ AUTOMOTIVE NETWORK COMMUNICATION PROTOCOL RENESAS ELECTRONICS CORPORATION IEEE 802.3br SPECIFICATION CONCERN We have some concern about Verifying of preemption