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Title: RE: WIS OH
In addition to simple loss of sync, If the "ELTE" has protection/maintenance switching functionality on the line side, it should be able to restore the optical circuit within a few milliseconds.  In this case, the MAC will see the ReceiveDataValid line be in the inactive state for only a few milliseconds.  For some systems, this will mean that some frames will be discarded.  Please see my presentation about how fast traffic can be restored over protection switched optical networks:
Thank you,
Roy Bynum
----- Original Message -----
Sent: Friday, June 09, 2000 8:57 AM
Subject: RE: WIS OH


Your description is correct. If you're asking how the WAN PHY will react to
Line/Path AIS, the pointer processor will detect AIS-P and the all ones
signal will be passed from the WIS up to the 66/64 decoder, which will lose
sync (e.g. LOD defect, Loss Of Delineation), then the MAC will see the
ReceiveDataValid line inactive & discard frames. 


    -----Original Message-----
    From:   Osamu ISHIDA []
    Sent:   Friday, June 09, 2000 6:24 AM
    To:     Martin, David [SKY:1I63-M:EXCH]
    Subject:        Re: WIS OH

    Hi Dave,

    Could you help me to understand how WAN-PHY and ELTE would react on
    SONET AIS (Alarm Indicaton Signal)?

    When we have cable cut in SONET infrastructure, the SONET side of
    the ELTE will receive either Line-AIS or Path-AIS.

      Line-AIS: all '1' in Line OH and SPE payload.
                generated by the regenerator who detect upstream cable cut.
                detected by the last 3 bits in K2 (at least 3 consecutive '111')
      Path-AIS: all '1' in AU pointer and SPE payload.
                generated by LTE who detect upstream cable cut.
                detected by the all '1' in H1&H2 at least 3 consecutive frames.

    Thank you,

    At 5:13 PM -0400 00.6.1, David Martin wrote:
    > Gary, Osamu,
    > Regarding the need for B2/M1. My thinking behind proposing B1 & B3/G1
    > only is that B1 is sufficient for fault isolation, and B3/G1 can serve
    > adequately for performance monitoring in the typical BER operating
    > range (a carrier can tap in with Intermediate Path Performance
    > Monitoring - IPPM).
    > Regarding the need for K1-2. I was thinking that protection switching
    > in the LAN is not a traditional feature. In the WAN, optical layer
    > protection could be used.
    > Roy has suggested using J1 Path Trace. I can see value in that.
    > But I believe if we add more OH beyond the WIS proposal (i.e. B1,
    > B3/G1, J0), save J1, we'll be crossing the line from compatible
    > to compliant & adding unnecessary cost.
    > ...Dave

    Osamu ISHIDA
    NTT Network Innovation Laboratories
    TEL +81-468-59-3263  FAX +81-468-55-1282