Enhancements to Ethernet AIS

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Enhancements to Ethernet AIS

• David Elie Dit Cosaque, Kamakshi Sridhar, Maarten
  Vissers, Tony Van Kerckhove

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Introduction

• Proposals for essential EthAIS functions
• EthAIS Coalescing
• EthAIS accurate alarm suppression

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Problem I EthAIS cascading
Multiple lower level faults result in multiple
EthAIS gtExcessive bandwidth consumption
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Solution EthAIS Coalescing

• Solution coalesce EthAIS in the MPs.
• Multiple faults at lower levels are seen as a
  single fault by higher levels
• Edge MPs will generate a new AIS with a
  different sequence number.

Benefits gtThe bandwidth taken by EthAIS at each
level is independent of the number of faults at
lower levels gtNo change in AIS frame format
required.
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Example EthAIS coalescing
Effectively solves the cascading problem without
requiring AIS frame format change
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Problem II EthAIS Alarm suppression inaccuracies

• gt Link failure alarms raised at server level, so
  CC loss alarm at any other level must be
  suppressed.
• However, dont want to suppress a CC loss due to
  customer fabric failure, because it is the only
  way to detect fabric faults.
• A mechanism to selectively alarm fabric failure
  CCLoss needed

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Solution TLV in AIS frame
CCLoss suppressed
CCLoss NOT suppressed
CCLoss suppressed

• EthAIS indicates which upper level MPs (MP1) are
  affected by a CCLoss
• Stored in a data base at edge MPs (Learning
  phase)
• New TLV in EthAIS containing MP1
• MP suppress CCLoss from MEs indicated in the
  EthAIS TLV (AIS TLV phase)

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Implementation EthAIS database

• Indicates which customer MPs are behind provider
  MPs

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How is the TLV (MP1) generated for AIS?

• MP1 is learnt from green CC.
• MP1 is installed in blue CC to populate the
  EthAIS database in MP3
• Additional TLV in CC frames

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Summary

• We propose
• a new Ethernet Coalescing scheme.
• One AIS generated for multiple lower level
  faults.
• a scheme for EthAIS accurate alarm suppression.
• Allows for CC loss due to fabric failures to be
  alarmed, inspite of EthAIS.
• EthAIS indicates unreachable upper level end
  point MPs

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