Transcript PPT Version

draft-sajassi-mohan-l2vpn-vpls-fm-00.txt
draft-mohan-sajassi-l2vpn-vpls-pm-00.txt
Dinesh Mohan (Nortel)
[email protected]
Ali Sajassi (Cisco)
[email protected]
IETF-59, Seoul
March 3, 2004
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Contributors & Acknowledgements
• Other contributors
– Shahram Davari (PMC Sierra)
– Nortel & Cisco colleagues
• Other Standards Participants
– ITU-T (Q.3/13)
– MEF
– IEEE (802.1 & 802.3)
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Scope of Current Work
• Within L2VPN Charter
– “L2VPN-specific OAM extensions--extensions to existing OAM solutions for
VPLS, VPWS, and IP-only L2VPNs”
– Fault and Performance Management within FCAPS
• Alignment with work in other bodies
– ITU-T Q.3/13, IEEE 802.1, MEF
NMS
Environment
• Focus on OAM
Procedures
across NEs
EMS-NMS Interface
EMS
EMS
EMS-NE Interface
NE
NE
Supplier Subnetwork
NE
NE
NE
NE
Supplier Subnetwork
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General Concepts – L2 OAM Framework
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VPLS OAM Layering – Service Layer
Customer
Service Provider
Customer
Eth Access
Device
View
CE
U-PE B
B
MPLS Core
N-PE
P
P
MPLS Access
P
N-PE
P
U-PE
Ethernet
Layer
Example Scenario with Single Service Provider Network
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CE
OAM Domain – Service/Network
Customer
Service Provider
Eth Access
Customer
MPLS Core
MPLS Access
Customer Domain
Provider Domain
Operator
Domain
Operator Domain
Operator
Domain
• Domains necessary to contain OAM flows &
bound OAM responsibilities
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Maintenance Points (MP) &
Intermediate Points (IP)
Customer
Service Provider
Eth Access
Customer
MPLS Core
MPLS Access
Customer Domain
Service
OAM
Provider Domain
Operator
Domain
Maintenance Point
Intermediate Point
Operator Domain
MPLS Domain
Network
OAM
Operator
Domain
PW/MPLS
OAM
MPLS
Domain
• Location of MPs and IPs is dependent on
Business Models & Deployment Scenarios
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VPLS OAM –
How diff. layers come together?
Services
Service OAM
Network
Network OAM
Transport
Links
Ethernet link
OAM
PW/MPLS
OAM
EoSONET
OAM
Other
OAM
• OAM Interworking possible to utilize OAM across Layers
• However, each layer must support OAM capabilities independently
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Maintenance Entities – MP2MP Case
Service Provider Y
User X
ETH_TFP ETH
TH_FP Link
Network Operator A
ETH_FP
UNI
ETH_TFP ETH
ETH_FP Link
User X
ETH ETH_TFP
ETH_FP Link ETH_FP
Network Operator B
ETH
ETH_FP Link
ETH_FP
NNI
UNI
ETH
ETH
ETH_FP
ETH ETH_TFP
ETH_FP Link ETH_FP
UNI
UNI
UNI_C to UNI_C maintenance entities
UNI_N to UNI_N maintenance entities
• MPs realize
Maintenance
Entities (MEs)
Intra Domain MEs
Access Link MEs
Intra Domain MEs
Inter Domain ME
Access Link MEs
• Note: Not all these MEs may be needed
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Fault Management
draft-sajassi-mohan-l2vpn-vpls-fm-00.txt
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Fault Management
• Typical steps involved
–
–
–
–
–
Fault Detection
Fault Verification
Fault Isolation
Fault Notification
Fault Recovery
• Focus of this draft is specifically on:
– Fault Detection
– Fault Verification
– Fault Isolation
• OAM Messages are sent across MEs within OAM domain
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Fault Management - Detection
• CC (Continuity Check)
–
–
–
–
–
Heartbeat message sent periodically
Sender does not expect acknowledgement
Receiver starts timer to expect periodic CC from sender
Loss of n consecutive CCs results in failure detection
Failures detected include:
• Hard and soft failures
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Fault Management - Verification
• Non-intrusive Unicast Loopback
– Verify the detected fault
– Sender sends a request to receiver and expects a response
• Receiver will typically be the one from whom CCs stop
• Verification is done via the response
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Fault Management - Isolation
• TraceRoute
– Sender sends a single request and IPs and receiver respond.
– Only selective Intermediate Points (IPs) respond
– Ethernet fault isolation is more challenging due to age-out of MAC
addresses (typically 5 minutes intervals)
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Fault Management – Information Elements
• Common OAM Information
–
–
–
–
–
–
OAM EtherType
OAM Version
OAM OpCode
Domain Level
Service ID
Transaction ID
• Requirements (Information Elements) need to be
discussed/agreed for VPLS
– Exact details (e.g.) frame formats will be worked out in coordination
with IEEE 802.1
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Performance Management
draft-mohan-sajassi-l2vpn-vpls-pm-00.txt
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Performance Management
• Typical steps involved
– Measurement of Performance Parameters
• Collection of managed objects information
• Calculation/Measurement of performance parameters
– Determination of compliance across:
• Service Level Specifications
• Network Level Specification
• Focus of this draft is specifically on:
–
–
–
–
–
Frame Loss Measurements
Frame Delay Measurements
Frame Delay Variation Measurements
Availability Measurements
Others parameters
• OAM Messages are sent across MEs within OAM domain
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Performance Management –
Measurement Mechanisms Options
• Level of accuracy
– Statistical Methods
• Sampling via OAM frames done to estimate the data path behavior
• Least accurate since OAM frames behavior could be quite different from data path
behavior
– Data path managed objects using management plane
• Data path managed objects used to make measurements, however, this information is
inserted via management plane
• Slight impact on accuracy since delay across data plane and management plane
interactions
• Mostly software based changes required
– Data path management objects using data plane
• Data path managed objects used to make measurements, however, this information is
inserted via data plane
• High accuracy since no delay across data plane and management plane interactions
• Hardware based changes needed in this case
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Performance Management –
Collection Method
• Generic method vs. specific method for specific
managed objects
– Recommendation for generic method e.g. use of TLVs
• Solicited (requiring response) vs. Unsolicited (not
requiring response)
– Recommendation to use both
– Possible to extend the Loopback and CC methods
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Performance Management –
Performance Parameters Measurements
• Frame Loss
– Unsolicited Method
– Solicited Method
– FL = |CT2-CT1| - |CR2-CR1|
• Frame Delay
– Round-trip or two-way delay
– Sender compares sent-timestamp with timestamp at receiving response
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Performance Management –
Performance Parameters Measurements
• Frame Delay Variation
– FDV = FD (max) – FD (min)
• Availability
– Availability = (# of available time intervals)/(# of total time intervals)
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What’s next?
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Next Steps
• Work Group Items?
– Further discussion & participation on VPLS OAM FM & PM work
• Coordination with:
– L2VPN Requirements
– Management Framework for OAM
• Continued coordination with other bodies
– IEEE 802.1
– ITU-T Q.3/13
– MEF
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