Date post: | 18-Dec-2015 |
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OAM capability Negotiation V1:
Require 3 bit in CV Type Indicator field for MS-OAM 0x01 ICMP Ping (predefined in [VCCV]) 0x02 LSP Ping (predefined in [VCCV]) 0x04 BFD for PW Fault Detection only (predefined in [VCCV]) 0x08 BFD for PW Fault Detection and AC/PW Fault Status Signaling (predefined in [VCCV]) 0x10 FDI 0x20 SEG OAM 0x40 E2E OAM
Problems: The length of the field is 8 bit, which limit the number of OAM capability indication.
V2: Reserve only 1 bit in CV type for MS-OAM. We suggest adding a new TLV indicating the OAM functions such as connectivity monitoring, fault notification and performance monitoring.
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Fault Notification
V2:
PW OAM should be detached from control plane.
Add fault notification (FDI/RDI) functions and message format.
Use 1 unused bit in CW to indicate the fault notification traffic.
It’s suggested to add fault notification functions in BFD.
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Misconnection Detecting
Misconnection is really unacceptable for customers. In this example customer X’s traffic is miss connected to customer Y in the intermediate SPE.
TPE_A SPE TPE_B
TPE_C
Customer_X Customer_X
Customer_YV2:
Add misconnect detecting function;
Define a new OAM PDU
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Next Step…
Performance Monitoring
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Thank you!
Your suggestions and/or comments are appreciated!
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Backup slides
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Why we need MS-OAM
A MS-PW will transit through multiple networks or domains.
If the PW experience failure or performance degrade, we must know which network/domain cause the problem.
TPE_A TPE_B SPE_1 SPE_2
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What are the differences?
MS-OAM SS-OAM
Continuity, RDI
2-Levels Single Level
FDImisconnect detecting
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Two OAM Levels in MS-OAM
E2E
Segment 1 Segment 2 Segment 3 Segment
TPE_A TPE_B SPE_1 SPE_2
MS-OAM provides E2E level and Segment level. Each level has its own functions and traffic.
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How to Encode Level Indicator
Extend three OAM channels defined in [VCCV]:
1.Control Word
Reserve one bit in CW.
0: Segment Level; 1: E2E Level
2.Router Alert
With this method, the E2E packets have to be processed at every intermediate node which will consume more resource, making this method not a preferred one.
3.TTL Expiry
Set the TTL value to the number of the hops/segments. But sometime it’s hard to get the detail of the hop info if the PW transmit across providers’ network.
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Why we need FDI
Fast Protection: The router which detect the fault first will send FDI to the far end the MS-PW which may initiate protection switching processing immediately.
Alarm Suppression: Eliminate duplicate alarms.
E2E
Segment 1 Segment 2 Segment 3
FDISegment
TPE_A TPE_B SPE_1 SPE_2
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How to support FDI functions?
There are two protocols used for PW-OAM:
1.LSP Ping
2.BFD
None of them supports FDI.
The method for sending FDI is described by draft-dong-pwe3-mspw-oam-02.txt. We think it’s necessary to add this functions in BFD and other OAM protocols used for PWE3.
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How to transmit RDI in MS-PW?
In SS-PW, remote defect indication is sent via PW status TLV in control plane.
In MS-PW, control plane may not exist. Under this circumstance, the remote defect indication can be sent via data plane.
The method for sending RDI is described by draft-dong-pwe3-mspw-oam-02.txt. We think it’s necessary to add this functions in BFD and other OAM protocols used for PWE3.
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What’s misconnection?
In this example customer X’s traffic is miss connected to customer Y in the intermediate SPE.
TPE_A SPE TPE_B
TPE_C
Customer_X
Customer_X
Customer_Y
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How to detect misconnection?
If the T-PE in the source end could send an OAM packet with its identifier to the sink end, misconnection could be detected.
A new OAM PDU is defined for misconnection detecting in draft-dong-pwe3-mspw-oam-02.txt.