Maintenance Adhoc Overview
Jeff MandinPMC-SierraJuly 2008
July 2008 802.3 Maintenance Adhoc 2
Background
1. 802.3-2005 describes two different interfaces to the MAC:
a) MA_DATA.Request/Indication in Clause 2- This is the ISO/IEC/802.1 interface
b) TransmitFrame()/ReceiveFrame() in Clause 4
2. In 802.3as it was determined that this “longstanding discrepancy” between the interface definitions should be remedied
- “Service to humanity”
- MAC Control sublayer no longer an “optional” sublayer inside the MAC but instead a MAC client
- State diagram added to reconcile MA_DATA.Request with TransmitFrame()
- MAC Control Clauses (31, 31B, 64) were modified to use the Clause 2 “service interface primitives” instead of the TransmitFrame()/ReceiveFrame() “functions”
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802.3-2005: MAC Control sublayer is part of MAC
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802.3ay D2.3: MAC Control sublayer no longer part of MAC
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State diagram from Clause 4 (802.3ay D2.2)
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An instance of impact on MAC Control that wasn’t recognized (Maint #1196)
1. There are cases where the TransmitFrame() function cannot simply be replaced by the MA_DATA.Request() primitive
- TransmitFrame() has “duration” ie. it does not complete until all supplied bits are transferred to the PHY
2. Clause 64 (Multipoint MAC Control) specifies the “Control Multiplexer” – which transmits frames to the MAC with extra gap time after IPG to enable the PHY to include FEC parity
3. In 802.3-2005, the Control Multiplexer relies on the duration of TransmitFrame() as part of its calculations of gap time
- When TransmitFrame() is replaced by MA_Data.Request(), this calculation needs to be modified
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MPCP Control Multiplexer
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Questions for the adhoc
1. Are there other instances in the MAC Control clauses (or elsewhere) that were affected by the MAC interface change?
- eg. Is the PAUSE operation transmit state diagram in figure 31B-1 in need of modification?
2. Is there a need to reevaluate the MAC interface changes affecting MAC Control?
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Backup
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PAUSE Operation Transmit State Diagram (Figure 31B-1)
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OAM Multiplexer State Diagram (Figure 57-7)