Break Link Proposal for 10-Gigabit Ethernet by yyc62487

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									Remote Fault & Break Link Proposal
     for 10-Gigabit Ethernet


             Howard Frazier
               Cisco Systems Inc.


              Shimon Muller
             Sun Microsystems Inc.



           New Orleans; September 12, 2000




                                                         1

                  IEEE 802.3ae
                  10 Gigabit Ethernet        S. Muller - Sun
Outline

s   Introduction
s   Concept
s   State Machines
s   What About OAM&P?
s   Summary




                                                          2

                        IEEE 802.3ae
                        10 Gigabit Ethernet   S. Muller - Sun
Introduction

s   This proposal provides a robust mechanism for supporting two
    (and exactly two) primitives
    s   Remote Fault
        s Indicates that a problem has been detected by the remote receiver

        s The source of the fault could be at:
           s Local transmitter
           s Interconnecting channel
           s Remote receiver

    s   Break Link
        s Intended to reset the channel and re-start the synchronization process



s   Both primitives indicate the occurrence of serious problems
    s   Totally preclude data exchange




                                                                                           3

                                       IEEE 802.3ae
                                     10 Gigabit Ethernet                       S. Muller - Sun
Concept

s   Break Link
    s   Low-level continuous signaling
        s K28.7 across all four lanes on XAUI

        s No alignment required

        s Mapped to a “reserved0” 64b/66b Control Frame for UniPHY

    s   Sent for the duration of ~10msec
        s During start up

        s When one end of the link loses synchronization

    s   Effect of receipt
        s Set the link status bit to “down”

        s Reset the link synchronization state machine and the de-skew logic




                                                                                           4

                                     IEEE 802.3ae
                                     10 Gigabit Ethernet                       S. Muller - Sun
Concept (continued)

s   Remote Fault
    s   Low-level continuous signaling
        s K28.1 interleaved with normal (randomized) Idle across all four lanes on XAUI

        s No alignment required

        s K28.1 is mapped to a “reserved1” 64b/66b Control Frame for UniPHY

    s   Sent forever
        s Whenever the local receiver cannot achieve synchronization

    s   Effect of receipt:
        s Keep the link status bit as “down”

        s Set the Remote Fault status bit when local receiver is in synch and it continues
           receiving RF signals
        s Once set, the Remote Fault status bit is only cleared when link status is “up”




                                                                                             5

                                      IEEE 802.3ae
                                     10 Gigabit Ethernet                         S. Muller - Sun
Transmit Synchronization State Machine
                                                                               Reset
                                                      START                BL_rcvd + !rx_in_sync
                                              Send BL                      UCT
                                              Enable 10ms_timer
                                              Clear link_up_status         10ms_timer_done * (BL_rcvd + !rx_in_sync) * !RF_rcvd
                                                                           10ms_timer_done * (BL_rcvd + !rx_in_sync)

                                                             10ms_timer_done

        NO_SYNC_2                                  NO_SYNC_1
                               !rx_in_sync
    Send 16 columns of Idle                    Send 16 columns of RF
                               !rx_in_sync

                                                             rx_in_sync

                                                    IN_SYNC_1
                                rx_in_sync
                                               Send Idle
                                               Enable 10ms_timer
                                               Clear RF_rcvd

                   10ms_timer_done * !BL_rcvd * rx_in_sync


                                                    IN_SYNC_2
                                                                          10ms_timer_done * RF_rcvd
                                               Send Idle
                                               Enable 10ms_timer
                                                                                                      FAULT
       10ms_timer_done * !BL_rcvd * rx_in_sync * !RF_rcvd
                                                                                              Set RF_status

                                                         UP
                                               Set link_up_status
                                               Clear RF_status

                                                                                                                                      6

                                                    IEEE 802.3ae
                                                   10 Gigabit Ethernet                                                    S. Muller - Sun
Receive Detection State Machines
         Reset                                          Reset                                            Reset
                             CLEAR                                          CLEAR                                         CLEAR
5ms_timer_done *
!rx_sync_detected Clear rx_in_sync                !BL_detected    Clear BL_rcvd                    clear RF_rcvd   Clear RF_rcvd



             rx_sync_detected                                                                         clear RF_rcvd         RF_detected
                                                      !BL_detected            BL_detected


                              SET                                            WAIT                                          WAIT
                      Set rx_in_sync                                 BL_count = BL_count + 1                       RF_count = RF_count + 1
                      Clear 5ms_timer


   rx_sync_detected        !rx_sync_detected   (BL_count = 255) * BL_detected                   (RF_count = 255) * RF_detected


                              WAIT                                           SET                                           SET
                   Enable 5ms_timer                              Set BL_rcvd                                       Set RF_rcvd




                 RX Synch Detection S.M.                 RX Break Link Detection S.M.                 RX Remote Fault Detection S.M.



Notes:
 * rx_sync_detected = signal_detect * pll_lock * lane0_in_sync * lane1_in_sync * lane2_in_sync * lane3_in_sync
* BL_detected = (lane0 = K28.7) * (lane1 = K28.7) * (lane2 = K28.7) * (lane3 = K28.7)
 * RF_detected = (lane0 = K28.1) * (lane1 = K28.1) * (lane2 = K28.1) * (lane3 = K28.1)


                                                                                                                                             7

                                                          IEEE 802.3ae
                                                          10 Gigabit Ethernet                                                    S. Muller - Sun
What About OAM&P?
s   There seems to be a wide consensus that OAM&P support in the
    WAN should be a mandatory function for 10 Gigabit Ethernet
s   To date, it does not appear that the same level of consensus ex-
    ists regarding the necessity of this function in LAN applications
s   If 802.3ae decides to provide support for OAM&P in the LAN, such
    a solution should architecturally easily scale to higher speeds
    s   LSS, as proposed, does not meet this requirement
        s Relies on the existence and a minimum duration of the IPG
           s What about 100 Gigabit Ethernet that uses 8-wavelength WDM?

s   Potential solutions:
    s   Use the WAN PHY in LAN applications
    s   Frame-based approach
        s Very low overhead --- OAM&P information requires very little bandwidth

        s Can use high level management frames (SNMP)

        s Alternatively, a low level MAC frame can be defined (similar to 802.3x)
                                                                                                8

                                      IEEE 802.3ae
                                     10 Gigabit Ethernet                            S. Muller - Sun
Summary
s   The proposed solution for Link Break and Remote Fault functions
    accomplishes the desired goals using a mechanism which is:
    s   Robust
        s Continuous signaling
        s No alignment required
        s Predictable behavior

    s   Simple and cheap
        s One state machine
        s Two timers
        s Two counters

    s   Scalable
        s Does not rely neither on the existence nor the duration of an IPG
        s Will work for all speeds (100-Gigabit Ethernet,....)

s   Support for OAM&P in the LAN is unrelated to LB/RF and should
    be considered on its own merits
s   We recommend that this proposal be adopted by 802.3ae as basis
    for further work for the 10-Gigabit Ethernet standard
                                                                                          9

                                       IEEE 802.3ae
                                      10 Gigabit Ethernet                     S. Muller - Sun

								
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