DraftmplstpOAMmaintnancepoints00

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Draft-mpls-tp-OAM-maintnance-points-00

• 11th Nov. 2009
• Hiroshima
• Yoshinori Koike / NTT

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Background
Carrier Grade packet transport network requires
MPLS-TP OAM function to be effective in
maintenance operations
If some faults or un-expected events occur,
quick actions and methods are mandatory in terms
of transport network requirements.
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Motivation of this I-D
Identifying the location of OAM maintenance
points (MIPs and MEPs) is the most significant
factor in MPLS-TP OAM framework. How and where
they are specified must be specified clearly
somewhere in the MPLS-TP framework document.
Why?
If OAM maintenance points are not appropriately
positioned, -the OAM function may be
meaningless, however excellent those OAM
functions are. -We cannot take appropriate action
and it takes a lot of time to solve a problem.
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Scope and objectives

• Clarify requirements regarding the location of
  maintenance points (MPs), that is, positions in
  MPLS-TP network and Network Element (NE) where
  OAM MPs need to be set
• Describe why these MPLS-TP OAM maintenance points
  are requested at those positions

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Potential problem and solution concerning MPs
Data flow
Type 1) MPLS Control Msg
NE
NE
Control packets are generated/received at one
point somewhere within an NE (Not clearly
specified)
NE
NE
Type 2) MPLS-TP OAM Msg
Egress
Ingress
Egress
Ingress
Control packets are generated from one point
somewhere within a NE
Regarding OAM packets, ingress and egress
distinction is requested for effective
maintenance operations (Points of interface, one
on each side of switching fabric)
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Typical maintenance operations
Quick location of fault point Scenario 1)
-Within one administrative domain or outside the
domain? Scenario 2) -Within a node or a
section (between two neighbor NEs)? Prompt
handling of the problem -Replacing fault
package(s) -Fixing or changing configuration
in package, port, section, logical path and so
on.
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Scenario 1 (within administrative domain or not)
Operators Administrative domain
Type1)
SN2(NE2)
SN3(NE3)
SN1(NE1)
Customer NE2
Customer NE1
P1
P2
P5
?
?
?
Customer domain
Customer domain
PW/LSP
Packet Loss
Packet Loss
MEP2
MEP1
MIP1
OK
Type2)
Customer NE2
Customer NE1
P2
P1
P3
P4
P5
P6
OK
?
?
Customer domain
Customer domain
PW/LSP
MEP1
MEP2
MIP1
MIP2
MIP3
MIP4
Loopback
OK
(1)
(2)
OK
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Scenario 2 (Within a node or section)
Operators Administrative domain
Type1)
SN2(NE2)
SN3(NE3)
SN1(NE1)
Customer NE2
Customer NE1
P1
P2
P5
?
?
?
Customer domain
Customer domain
PW/LSP
Packet Loss
Packet Loss
MEP2
MEP1
MIP1
NG
Type2)
Customer NE2
Customer NE1
P2
P1
P3
P4
P5
P6
OK
?
?
Customer domain
Customer domain
PW/LSP
MEP1
MEP2
MIP1
MIP2
MIP3
MIP4
Loopback
OK
(1)
(2)
NG
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Requirements

• 1) At the intermediate node on PW/LSP, it should
  be possible to activate two MIPs, one on each
  side of the switch fabric/forwarding part.
• 2) At the edge node on PW/LSP, it should be
  possible to activate one MIP and one MEP, one on
  each side of the switch fabric/forwarding part.
• 3) If OAM is supported, MEPs have to be active at
  all times when the LSP is set, an MIP only has to
  be activated when it is necessary or required
  (e.g. for fault location). (That is, an MIP does
  not need to be active at all times.)

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Next Steps

• Planning to work further on the text
• -Add other OAM requirements and their backgrounds
  (ex. Delay measurement, Packet Loss measurement)
• -Clarification of the meaning of Loop back
• LBM/LBR or traffic loopback?
• Loop back as a tool or as a function?
• -Requirements need to be developed and modified
• Distinction between purpose and means,
  Additional terminology (Ingress and egress)
• Soliciting comments, feedback and suggestions for
  this draft from WG

Type1)
Large factor in packet delay or packet loss
Type2)
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Thank you