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Major Changes
Message formatDropped use of ACH-TLVs
Extended flag fields
Replaced LDI message with an “LDI Flag” on the AIS message
Added IANA Section
Added Security Section
General editing
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Dropped use of ACH-TLVsAfter talking with many hardware engineers, decided that these were not particularly silicon friendly
Important stuff for hardware is in fixed locations
Moved information into TLVs internal to the message
These can be stored for examination by software or punted up to software
Extended flag fieldsAdded another flag, which left only two, so changed format to allow for eight
Could allow for message format alignment with other drafts
Message format
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Link Down Indication
Replaced LDI message with an “LDI Flag” on the AIS message
LDI is only need when CC is running slowlyIf CC is running fast (detect time ~500 ms or less) then LDI is treated just like AIS
Semantics and the procedures remain the same
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Link Down Indication (LDI)
Setting the LDI flag is driven from the APS state
LDI flag must be set whenever the server layer enters the unavailable state
When LDI is received by an MPLS-TP LSP’s MEP it is used to
Suppresses alarms due to any CC failure – just like AIS
May be used to trigger path protection
e.g. CC is running slowly and no CC failure has occurred
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AIS / LDI Fault Generation
Client LSP
Server Working LSP
Server Protection LSP
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Example 1: An unprotected link
Server Path is unprotected
Control function tells Server MEP W to set LDI flag when generating AIS messages
Server Path WServer Path WServer MEP WServer MEP W
Client PathClient Path
Server APS/Control
Server APS/Control
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Example 2: Both Working and Protection are Up
CC functions are reporting that both W and P are up
APS is in the Normal State
Control Function tells both MEPs to clear the LDI flag when generating AIS messages
Server LSP PServer LSP P
Server LSP WServer LSP W
Server MEP PServer MEP P
Server MEP WServer MEP W
Client PathClient Path
Server APS/Control
Server APS/Control
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Example 3: Protection Up, Working Fails
Server LSP W fails, Server MEP W begins sending AIS with LDI = 0
APS / Control Function moves selector to Protection LSP
AIS ceases to be inserted in Client LSP
APS enters Protecting State, Control Function tells Server MEP P to set LDI flag (= 1) when generating AIS messages
Server LSP PServer LSP P
Server LSP WServer LSP W
Server MEP PServer MEP P
Server MEP WServer MEP W
Client LSPClient LSP
X
Server APS/Control
Server APS/Control
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ACH Codepoint
An ACH Codepoint was requested through the early allocation procedures
The codepoint has been assigned 0x0058 Fault OAM (TEMPORARY - expires 2011-07-16)
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Next Steps
Add a more complete section about setting LDI Flag
Address any comments
Republish
Request last call
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