carrier ethernet tech overview
TRANSCRIPT
Carrier Ethernet:: Technology Overview and Testing Solution
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Carrier Ethernet:: Big Picture
Wireless Backhaul
Voice Gateway
Voice/VideoTelephony
HD TVTVoD, VoD
Gaming, BusinessBackup, ERP
ResidentialTriple-Play
VideoSource
VideoSource
Small/Medium Business
Internet
FTTx and DSLAM , Cable Modem
E-Line andE-LAN service
Source: MEF (www.metroethernetforum.net)
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Carrier Ethernet Services
Ethernet based metro services primarily for businesses
Lower cost and simpler version of leased-line, Frame Relay and ATM services
L2 Ethernet connectivity with SLA that defines several characteristics
Performance parameters such as CIR, EIR, frame loss ratio, latency and latency
variation (jitter)
Ethernet service definitions by the Metro Ethernet Forum (MEF)
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Driving Factors for Carrier Ethernet Ubiquitous
Most data traffic starts and ends on an Ethernet port
Cost Effective
Equipment port costs lower than Frame Relay or ATM
Significantly lower provisioning costs
Simple
Protocols are widely understood and easy to use
Rapid, on-demand provisioning
Quickly add services and bandwidth
High degree of bandwidth granularity
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Enterprise Ethernet vs. Carrier Ether
Device Characteristic Enterprise SR CE SR
Customer Enterprise Service provider
High availability STP/RSTP MSTP/RSTP/STP, graceful restart, Fast re-route
Routing protocols OSFP, BGP, RIP, multicastMPLS/VPLS, OSPF, ISIS, BGP, RIP, multicast
routing
Services MP-to-MP, VLANMEF E-Line, E-LAN, E-Tree, VLAN, L3 VPNs,
Ethernet aggregation (PPPoE/PON)
VLANs Hundreds Thousands
Bridging 802.1Q 802.1Q, 802.1ad, 802.1ah, PBB-TE
OAM SNMP 802.3ah, 802.1ag/Y.1731
Traffic shaping/policing None or limited Per EVC
SLAs None With guaranteed frame latency, jitter, loss ratio
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Agenda
Carrier Ethernet Overview
MEF’s Service Definition & Certification
Ethernet OAM
Service OAM (a.k.a. CFM, defined in IEEE 802.1ag/ITU-T Y.1731)
Link OAM (a.k.a. EFM, defined in IEEE 802.3ah)
Bridging & Transport Technologies
PB (802.1ad/Q-in-Q), PBB (802.1ah/Mac-in-Mac)
PBB-TE (PBT/802.1Qay), T-MPLS
Testing Carrier Ethernet
Summary
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What is the MEF?
The Metro Ethernet Forum is a non-profit organization chartered with the mission of accelerating worldwide adoption of carrier class Ethernet networks and services.
Comprised of:
Service Providers, Carriers
NEMs, Chip and Component Vendors
Test Equipment Vendors, Labs
Produces:
Marketing Collateral and Evangelism
Whitepapers, Success Stories, Interoperability Demos, Case Studies
Implementation Agreements
Test Procedures
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MEF Standards Scope
MEF is not a standards body.
Produces Implementation Agreements that are technical documents that use
existing standards.
Implementations are agreed to by MEF members
Makes recommendations to standards bodies (called Positioning
Statements)
Creates specifications (as a last resort) if not addressed by standards
bodies or outside the scope of the standards bodies.
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MEF 18 Abstract Test Suite for CES over Ethernet (TS)
MEF 16 – Ethernet Local Management Interface E-LMI (TS)
MEF 11 - UNI Framework and Requirements (TS)
MEF 3 – Circuit Emulation Service Requirements (TS)
UNI Type 2 (IA)
MEF 19 Abstract Test Suite for UNI Type 1 (TS)
MEF 17 Service OAM Requirements and Framework (TS)
MEF 12 – Metro Ethernet Network Architecture Framework Part 2: Ethernet Services Layer (TS)
MEF 8 Emulation of PDH over MENs (IA)
MEF 14 – Abstract Test Suite for Traffic Management Phase 1 (TS)
MEF 15 – Requirements for Management of Metro Ethernet Phase 1 – Network Elements (TS)
MEF 4 – Metro Ethernet Network Architecture Framework Part 1: Generic Framework (TS)
MEF 9 – Abstract Test Suite for Ethernet Services at the UNI (TS)
MEF 7 – EMS - NMS Information Model (TS)
MEF 2 – Protection Framework and Requirements (TS)
MEF 6 – Ethernet Services Definitions (TS)
Abstract Test Suite for E-NNI (TS)EMS-NMS Information Model (TS) Phase 2
MEF 13 – User Network Interface Type 1 (IA)
MEF 10.1 Ethernet Services Attributes Phase 2 (TS)
UNI Type 2 Test Suite (TS)
External NNI (E-NNI) Phase 1 (TS)
Ethernet Services Definitions Phase 2 (TS)
Test and Measurement AreaManagement AreaArchitecture AreaService Area
TS Technical SpecificationIA Implementation Agreement
* MEF 10.1 replaced MEF 10. which replaced MEF 1 and MEF 5
MEF Standards Process and LegendLetterBallot
NewProject
ApprovedDraft
StrawBallot
ApprovedSpecification
Aggregation Interface (TS)
Wireless Backhaul (IA)
May 2007
Class of Service (TS)
NID Specification (TS)
Service OAM (IA)
UNI Type 2 Test Suite, Part 1 link OAM (TS)
The Technical Work of the MEF
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• MEF 2 Requirements and Framework for Ethernet Service Protection • MEF 3 Circuit Emulation Service Definitions, Framework
and Requirements in Metro Ethernet Networks • MEF 4 Metro Ethernet Network Architecture Framework
Part 1: Generic Framework• MEF 6 Metro Ethernet Services Definitions Phase I • MEF 7 EMS-NMS Information Model • MEF 8 Implementation Agreement for the Emulation of PDH Circuits
over Metro Ethernet Networks• MEF 9 Abstract Test Suite for Ethernet Services at the UNI• MEF 10.1 Ethernet Services Attributes Phase 2*• MEF 11 User Network Interface (UNI) Requirements and Framework • MEF 12 Metro Ethernet Network Architecture Framework
Part 2: Ethernet Services Layer• MEF 13 User Network Interface (UNI) Type 1 Implementation Agreement• MEF 14 Abstract Test Suite for Traffic Management Phase 1 • MEF 15 Requirements for Management of Metro Ethernet
Phase 1 Network Elements• MEF 16 Ethernet Local Management Interface• MEF 17 Service OAM Framework and Requirements• MEF 18 Abstract Test Suite for Circuit Emulation Services• MEF 19 Abstract Test Suite for UNI Type 1
* MEF 10 .1 replaces and enhances MEF 10 Ethernet Services Definition Phase 1 and replaced MEF 1 and MEF 5.
Approved MEF Specifications
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MEF’s Ethernet Service Definition
Carrier Ethernet Terminology
The UNI, NNI, MEN.
Ethernet Virtual Connections (EVCs)
EVCs and Services
E-Line Services
Ethernet Private Line
Ethernet Virtual Private Line
E-LAN Services
Multipoint Services
E-Tree Services
Service Attributes
Service Parameters
Bandwidth Profiles
Traffic Management
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MEF Carrier Ethernet Terminology
User Network Interface (UNI) Type I
A UNI compliant with MEF 13
Manually Configurable
UNI Type II
Automatically Configurable via E-LMI*
Manageable via OAM*
Metro Ethernet Network (MEN)
An Ethernet transport network connecting user end-points in a Metro network
Carrier Ethernet Network (CEN)
Expansion from the original MEN concept to encompass Access & Global networks in addition to the original Metro network
Network to Network Interface (NNI)
Network to Network Interface between distinct CENs operated by one or more carriers
An active project of the MEF
* E-LMI: Ethernet Local Management Interface. OAM: Operations, Administration and Maintenance
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MEF Terminology Diagram
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Carrier Ethernet Network
UNIUNI
MEF Carrier Ethernet TerminologyThe User Network Interface (UNI)
The UNI is the physical interface or port that is the demarcation between the customer and the service provider/Cable Operator/Carrier/MSO
The UNI is always provided by the Service Provider
The UNI in a Carrier Ethernet Network is a physical Ethernet Interface at operating speeds 10Mbs, 100Mbps, 1Gbps or 10Gbps
The UNI is often co-located with the CE at the customer’s premises
CE: Customer Equipment MEF certified Carrier Ethernet products
CECE
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MEF Carrier Ethernet Terminology
Ethernet Virtual Connection (EVC) Service container
Connects two or more subscriber sites (UNIs)
An association of two or more UNIs
Prevents data transfer between sites that are not part of the same EVC
Three types of EVC
Point-to-Point
Multipoint-to-Multipoint
Rooted Multipoint
Can be multiplexed on the same UNI
Defined in MEF 10.1 technical specification
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EVCs and Services
In a Carrier Ethernet network, data is transported across Point-to-Point and Multipoint-to-Multipoint EVCs according to the attributes and definitions of the E-Line and E-LAN services
Point-to-Point EVC
Carrier Ethernet NetworkUNIUNI UNIUNI
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Two Common Service Types
E-Line Service used to create
Ethernet Private Lines
Virtual Private Lines
Ethernet Internet Access
E-LAN Service used to create
Multipoint L2 VPNs
Transparent LAN Service
Foundation for IPTV and Multicast networks etc.
E-Line Service type
E-LAN Service type
Point-to-Point EVC
Carrier Ethernet Network
UNI: User Network Interface, CE: Customer Equipment
CECE
UNIUNI UNIUNI
CECE
Multipoint-to-Multipoint EVC
Carrier Ethernet Network
CECE
UNIUNI
MEF certified Carrier Ethernet products
CECE
UNIUNI
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Services Using E-Line Service Type Ethernet Private Line (EPL)
Replaces a TDM Private line
Dedicated UNIs for Point-to-Point connections
Single Ethernet Virtual Connection (EVC) per UNI
The most popular Ethernet service due to its simplicity
Point-to-Point EVC
Carrier Ethernet Network
CECE UNIUNI
CECEUNIUNI
CECE
UNIUNI
ISPPOP
UNIUNI
Storage Service Provider
Internet
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UNIUNI
Services Using E-Line Service Type
Ethernet Virtual Private Line (EVPL) Replaces Frame Relay or ATM services
Supports Service Multiplexed UNI (i.e. multiple EVCs per UNI)
Allows single physical connection (UNI) to customer premise equipment for multiple virtual connections
Carrier Ethernet Network
CECEUNIUNI
CECEUNIUNI
Point-to-Point EVC
CECE
ISPPOP
Internet
Service Multiplexed
Ethernet UNI
CECE
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Services Using E-LAN Service Type
Ethernet Private LAN and Ethernet Virtual Private LAN
Services
Supports dedicated or service-multiplexed UNIs
Supports transparent LAN services and multipoint Layer 2 VPNs
E-LAN Service type
Multipoint-to-Multipoint EVC
CECE
UNIUNI
CECE
UNIUNI
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Services Using E-Tree Service Type Ethernet Private Tree (EP-Tree*) and Ethernet Virtual Private Tree (EVP-Tree)
Services
Provides traffic separation between users with traffic from one “Leaf” being allowed to
arrive at one or more “Roots” but never being transmitted to other “Leaves”
Targeted at multi-host and franchised applications where user traffic must be kept
invisible to other users
Root
Carrier Ethernet Network
CECEUNIUNI
UNIUNI
UNIUNI
CECE
UNIUNI
CECE
Leaf
Leaf
UNIUNI
CECE
Leaf
* Referenced in MEF 10.1 as Rooted-Multipoint EVC
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Service Parameters
EVC Service Attributes
Details regarding the EVC including
QoS assignment and tagging options
Bandwidth Profiles
Latency
Frame Loss
Frame Delay Variation
Bandwidth Profiles
Committed Information Rate
Excess Information Rate
Rate Enforcement - shaping and policing
Burst Size (window)
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EVC Service Attributes
Service Attribute Service Attribute Parameters
EVC Type Point-to-Point or Multipoint-to-Multipoint
EVC ID A string identifier, unique across the MEN, for the EVC supporting the service instance
UNI List A list of UNIs (identified via the UNI Identifier service attribute) used with the EVC
CE-VLAN ID Preservation Yes or No. Specifies whether customer VLAN ID is preserved or not.
CE-VLAN CoS Preservation Yes or No. Specifies whether customer VLAN CoS (802.1p) is preserved or not.
Unicast Service Frame Delivery Discard, Deliver Unconditionally, or Deliver Conditionally
Multicast Service Frame Delivery Discard, Deliver Unconditionally, or Deliver Conditionally
Broadcast Service Frame Delivery Discard, Deliver Unconditionally, or Deliver Conditionally
Layer 2 Control Protocol Processing Discard or Tunnel per protocol
Service Performance Performance objectives for Frame Delay, Frame Jitter and Frame Loss
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UNI Service Attributes
Service Attribute Service Attribute ParametersUNI Identifier A string used to identity of a UNI
Physical Medium Standard Ethernet PHY
Speed 10 Mbps, 100 Mbps, 1 Gbps or 10 Gbps
Mode Full Duplex or Auto-Negotiation
MAC Layer IEEE 802.3-2002
Service Multiplexing (VLANs) Yes or No. Defines whether multiple services can be on the UNI
UNI EVC ID A string concatenation of the UNI ID and EVC ID
CE-VLAN ID for untagged & priority service frames
1 to 4094
CE-VLAN ID / EVC Map Mapping table of customer VLAN IDs to EVC
Maximum Number of EVCs The maximum number of EVCs allowed per UNI
Bundling Yes or No. Specifies that one or more customer VLAN IDs are mapped to an EVC at the UNI
All to One Bundling Yes or No. Specifies if all customer VLAN IDs are mapped to an EVC at the UNI
Ingress Bandwidth Profile Per Ingress UNI None or <CIR, CBS, EIR, EBS>. This Bandwidth profile applies to all frames across the UNI.
Ingress Bandwidth Profile Per EVC None or <CIR, CBS, EIR, EBS>. This Bandwidth profile applies to all frames over particular EVC.
Ingress Bandwidth Profile Per CoS ID None or <CIR, CBS, EIR, EBS>. This Bandwidth profile applies to all frames marked with a particular CoS ID over an EVC.
Layer 2 Control Protocol Processing Discard, Peer or Pass to EVC per protocol
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CIR and EIR Bandwidth Profiles
BW profiles per EVC
CIR – Committed Information Rate
Frame delivery obligation per SLA
EIR – Excess Information Rate
Excess frame delivery allowed – not subject to
SLA if available
CBS, EBS - size of burst window (ms) for
allowed CIR / EIR rates
Total UNI Bandwidth
EVC1
CIR
EIREVC2
CIR
EIR
EVC3
CIR
EIR
2 rate, 3 Color marking Marking typically done at ingress port of service provider equipment
Green Forwarded frames – CIR conforming traffic Yellow Discard Eligible frames – Over CIR , within EIR Red Discarded frames – Exceeds EIR
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UNI
EVC 1
EVC 2
EVC 3
Ingress Bandwidth Profile Per Ingress UNI
UNI
EVC 1
EVC 2
EVC 3
Ingress Bandwidth Profile Per EVC1
Ingress Bandwidth Profile Per EVC2
Ingress Bandwidth Profile Per EVC3
UNI EVC 1
CE-VLAN CoS* 6 Ingress Bandwidth Profile Per CoS ID 6
CE-VLAN CoS 4
CE-VLAN CoS 2
Ingress Bandwidth Profile Per CoS ID 4Ingress Bandwidth Profile Per CoS ID 2
EVC 2
Port-based Port/VLAN-based
Port/VLAN/CoS-based
MEF 10.1 Traffic Management Model
* CoS: Class of Service
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Bandwidth Profile Parameters
Committed Information Rate (CIR)Bits per second
(CIR ≥ 0)
Committed Burst Size (CBS)Bytes
(CBS ≥ max frame size)
Excess Information Rate (EIR)Bits per second
(EIR ≥ 0)
Excess Burst Size (EBS)Bytes
(EBS ≥ max frame size)
Coupling Flag0 or 1
(Determines Yellow rate bounds)
Color ModeColor-blind or
Color-aware
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Algorithm
Frames are marked as Green, Yellow, or Red at the Ingress to the MEN
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Color Treatment
Red Discard
Yellow Deliver
But SLS does not apply
Green Deliver
SLS applies
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Frame Loss Ratio Performance
Service frame is lost if it should have been delivered but was
not delivered
Defined by parameters T and L
Performance objective is met if no more than L% of the service
frames [ that arrive at the ingress UNI during interval T and have a
green bandwidth profile] are lost
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Frame Delay Performance
Defined as the time elapsed from reception at the ingress UNI of the first bit of the ingress Service Frame until the transmission of the last bit of the Service Frame at the egress UNI.
One-way delay
Defined as a P-Percentile with parameters T, P, and d
Performance objective met if at least P% of the service frames [that arrive at the ingress UNI during the interval T, have a green bandwidth profile, and are delivered at the egress UNI] have a delay ≤ d
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Frame Delay Variation Performance Defined for pairs of service frames
Delay of first service frame minus delay of second service frame
Defined as a P-Percentile with parameters T, P, Δt, v Performance objective met if at least P% of service frame pairs [ that
arrive at the ingress UNI during interval T, are sent Δt apart, have a green bandwidth profile, and are delivered to the egress UNI] have differences in frame delay ≤ v
di dj
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SLAs
CoS based SLAs with Service Level Specifications (SLS) and guarantees are required for mission critical enterprise applications
Bandwidth Profile is defined to characterize the traffic (Ingress Service Frames) at the UNI
Each frame is either compliant or not compliant
Bandwidth Profile is enforced by the provider’s network
EVC Related Performance Service Attributes are defined to specify the Service Frame delivery performance
Frame Delay Performance
Frame Delay Variation Performance (Jitter)
Frame Loss Ratio Performance
Both the Bandwidth Profile and Performance Service Attributes are defined in MEF 10.1.
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Sample SLA with 4 CoS
Service Class Application CoS Bandwidth Profile per
EVC per CoS IDService
Performance
Platinum Real-time voice and video 6, 7CIR > 0
EIR = 0
P=99.9%, T=600s
L=0.001%
d=5ms
v=1ms
GoldBursty mission critical data applications requiring low loss and delay (e.g., storage)
4, 5CIR > 0
EIR ≤ UNI Speed
P=99%, T=600s
L=0.01%
d=5ms
v=N/S
SilverBursty data applications requiring bandwidth assurances
3, 4CIR > 0
EIR ≤ UNI Speed
P=95%, T=600s
L=0.1%
d=15ms
v=N/S
Standard Best effort service 0, 1, 2CIR=0
EIR=UNI speed
P=90%, T=600s
L=0.5%
d=30ms
v=N/S
MEF Certification
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MEF Membership Continues to MEF Membership Continues to Increase Increase
MEF Certified Services and Devices MEF Certified Equipment Manufacturers and Service Providers
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MEF Certification ProgressMEF Certification Progress
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MEF 9 Tests Service Compliance
MEF 9 tests conformance of Ethernet Services at the UNI where the Subscriber and Service Provider
areas of responsibility meet
Guarantee that subscribers can confidently order Ethernet EPL, EVPL and E-LAN services that conform
to MEF service specifications
Essential for large enterprises receiving Ethernet services from multiple providers
More attractive Ethernet services to enterprise subscribers with strict requirements for service quality
Testers generatingTesters generatingreceiving monitoringreceiving monitoringframesframesat the UNIat the UNI
Testers generating Testers generating receiving monitoringreceiving monitoring
framesframesat the UNIat the UNI
Testers physically attach to the MEN at the UNITesters physically attach to the MEN at the UNI
Testers may be attached to the MENTesters may be attached to the MENat multiple UNIsat multiple UNIs
User NetworkUser NetworkInterface (UNI)Interface (UNI)
MetroMetroEthernetEthernetNetworkNetwork
User NetworkUser NetworkInterface (UNI)Interface (UNI)
Test Bed for Ethernet Services at the UNITest Bed for Ethernet Services at the UNI
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Traffic Management Testing based on MEF 10:
Section 6.7 which defines EVC Related Performance Service Attributes:
Frame Delay Service Performance
Frame Delay Variation Service Performance
Frame Loss Ratio Service Performance
Section 7.10 which defines Bandwidth ProfilesService Attributes:
Bandwidth Profile Rate Enforcement
Bandwidth Profile per Ingress UNI
Bandwidth Profile per EVC
Bandwidth Profile per Class of Service
Multiple Bandwidth Profiles at the UNI
Service Quality:: The Next Step in Carrier Ethernet Compliance Testing
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MEF 14:: Standards Based SLS/SLA Verification of Service Quality
SLA (Service Level Agreement) refers to the contractual obligations binding the Subscriber and the Service Provider
SLS (Service Level Specification) refers to the parameters of the performance objectives
Based on Traffic Management specifications in MEF 10
Ethernet Service Performance Attributes
Frame Delay Service Performance
Frame Delay Variation Service Performance
Frame Loss Ratio Service Performance
Measured per EVC and per Class of Service
Requires continuous, accurate, accountable measurements on operational networks
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Agenda
Carrier Ethernet Overview
MEF’s Service Definition & Certification
Ethernet OAM
Service OAM (a.k.a. CFM, defined in IEEE 802.1ag/ITU-T Y.1731)
Link OAM (a.k.a. EFM, defined in IEEE 802.3ah)
Bridging & Transport Technologies
PB (802.1ad/Q-in-Q), PBB (802.1ah/Mac-in-Mac)
PBB-TE (PBT/802.1Qay), T-MPLS
Testing Carrier Ethernet
Summary
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EOAM
Ethernet Operations, Administration and Maintenance
Used to help service providers provision and troubleshoot Ethernet services
Consists of various management messages sent between two or more network
elements
Messages are processed to provide information about connectivity or the existence of
error conditions
Three primary specifications exist today:
IEEE 802.3ah – a.k.a. Link OAM or Ethernet in the First Mile (EFM)
IEEE 802.1ag – a.k.a. Service OAM or Connectivity Fault Management (CFM)
ITU-T Y.1731 - OAM Functions and Mechanisms for Ethernet based Networks
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Standard Bodies Working on CE
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EOAM Protocols
Link OAM (EFM: Ethernet in the First Mile)
IEEE 802.3ah defines OAM messages between two devices only,
typically a CPE and access device
Service OAM (CFM)
Both 802.1ag and Y.1731 define OAM messages that can be used
to verify service connectivity across many network elements and at
different hierarchies (customer, operator, provider, etc.)
MEF is working on EOAM Implementation Agreement (E-LMI)
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Service OAM:: Two Standard Bodies
IEEE 802.1ag defines “Connectivity Fault Management” for all IEEE 802
Bridges
ITU-T Question 3, Study Group 13, is defining end-to-end Ethernet OAM
for both circuit-switched equipment (e.g., Ethernet over SONET) and
packet-switched equipment (802.1ad Bridges)
Both share common membership and are cooperating fully
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MEPs, MIPs and ME Levels
Source: White paper by Fujitsu “Ethernet Service OAM: Overview, Applications, Deployment, and Issues”
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Service OAM Terminology
Maintenance Points
MP is a demarcation point on an interface (port) that participates in EOAM within a Maintenance Domain
Two classes of MPs
Maintenance End Points (MEPs): at the edge of a Domain
Actively source EOAM messages
Directional (inward or outward facing)
Maintenance Intermediate Points (MIPs): Internal to a Domain
Passive points, only respond when triggered by certain CFM messages
MPs should be explicitly provisioned
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Service EOAM Structure
Structure Messages are standard Ethernet frames with special MAC addresses,
EOAM ether type, and EOAM-specific TLVs
Provides multiple levels to accommodate a hierarchy of MAs/MEGs between customer, provider and operators
IEEE 802.1ag and ITU-T Y.1731 share the same base frame format But, they’re not necessarily interoperable!
Nomenclature 802.1ag Y.1731 Comment
Administrative domain
MA (Maintenance association)
MEG (Maintenance entity group)
Administrative domain consisting of MEs that belong to the same Ethernet service
EOAM device ME (Maintenance entity) – MEP or MIP Switch or router supporting EOAM
EOAM end point MEP (MA end point) MEP (MEG end point) Node that terminates and initiates EOAM messages
EOAM intermediate point
MIP (MA intermediate point)
MIP (MEG intermediate point)
Node that lies along the path of an Ethernet service but only reacts to EOAM messages
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Service EOAM Messages
All EOAM messages are per Maintenance Domain and per S-VLAN (PE-VLAN or Provider-VLAN)
Regular Ethernet Frames, distinguishable by Destination MAC and/or Ethertype
Provider bridges that cannot interpret EOAM messages must forward them as normal data frames
Three Major Types of Messages:
Continuity Check (CC)
Loopback
Link Trace
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Common Ethernet Service OAM Frame Format
Source: White paper by Fujitsu “Ethernet Service OAM: Overview, Applications, Deployment, and Issues”
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Common Service EOAM Functions ETH-CC (Continuity Check)
Beacon – used to detect loss of continuity between MEPs
Can be used for fault management, performance monitoring and APS applications
ETH-LB (Loop-Back: analogous to IP Ping)
Used to verify bi-directional connectivity of MEP with other MPs in MA/MEG
Can be used to verify service – throughput, bit error detection, etc.
ETH-LT (Link-Trace: analogous to IP TraceRoute)
Returns list of MPs connected on path to MEP
Can be used for adjacency retrieval (discovery) and to detect faults or loops
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Additional EOAM Functions
Y.1731 only
Ethernet Alarm Indication Signal (ETH-AIS)
Secondary fault management functions (Y.1731 only)
Test, LCK, MCC, EXP, VSP
Performance Management
Loss measurement (LM)
Delay measurement (DM)
Protection Switching
Related to 1731 but detailed in G.8031
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IEEE 802.1ag vs. ITU-T Y.1731
Similarities Both use same Ethernet frame type – EOAM
Both use the same OAM header – Level, Version, OpCode, Flags, First TLV Offset
Both have CC, LT, and LB functions with the same OpCodes Both also support RDI
Both use End, Data, Reply Ingress and Reply Egress TLVs
Both use same MEP ID format
Differences Each has its own set of reserved OpCodes
802.1ag specifies optional Sender ID, Port Status, Interface Status TLVs
802.1ag makes use of optional sequence number in CCMs
Y.1731 supports AIS function
Each has a different group ID format 802.1ag MAID (Primary VID, character string, 2-byte integer, RFC 2865) with domain name
1731 uses MEG ID
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802.3ah Link OAM:: Now “802.3-2005 Clause 57”!!!
Link Level point-to-point OAM using OAMPDUs
Messages are never propagated beyond a single hop
Monitor health of a link
Determine location of failing links or fault conditions
Complement applications in higher layers
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Five Main Functions of Link OAM
OAM discovery
Discover OAM capabilities on peer device
Link monitoring
Event notification when error thresholds exceeded
Remote MIB variable retrieval
Polling and responses or remote MIB
Remote Failure indication
Inform peer that receive path is down
Remote Loopback
Puts peer in intrusive loopback state. Stats can be collected while testing link
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802.3ah OAMPDU Format
Destination address: 01-80-C2-00-00-02 Slow protocol address
Ether-Type: 88-09
Subtype: 03
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Layering OAM
Model is iterative & relative (service layer for Operator is transport layer for SP)
Each layer supports its own OAM mechanisms
Inter-working across and within OAM layer is possible & necessary
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Example of OAM Interworking
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Agenda
Carrier Ethernet Overview
MEF’s Service Definition & Certification
Ethernet OAM
Service OAM (a.k.a. CFM, defined in IEEE 802.1ag/ITU-T Y.1731)
Link OAM (a.k.a. EFM, defined in IEEE 802.3ah)
Bridging & Transport Technologies
PB (802.1ad/Q-in-Q), PBB (802.1ah/Mac-in-Mac)
PBB-TE (PBT/802.1Qay), T-MPLS
Testing Carrier Ethernet
Summary
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Switched Ethernet Issues
Performance
MSTP convergence time – faster than STP but still slow
Efficiency
Under-utilization of bandwidth due to spanning tree path blocking
MSTP helps but can be complex to configure
Provisioning
Labor intensive VLAN & MSTP configuration
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Switched/Bridged Ethernet
Customer PremisesSite A
EthernetSwitch
SwitchedEthernet Core
Customer PremisesSite B
Customer PremisesSite C
Use Ethernet switches/bridges throughout the network
Customer networks provisioned in separate VLANs
Redundancy and resiliency via MSTP
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Spanning Tree
Needed to prevent loops in the network
STP allows only one path
MSTP allows different paths for each VLAN
All traffic takes the path between S3
and S1
Switch 3
Switch 1Root
Switch 2
3
Blocking
Central Office
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MSTPCustomer Premises
Sites A
EthernetSwitch
SwitchedEthernet Core
MSTP
Multipoint to multipoint traffic for VLAN 1Multipoint to multipoint traffic for VLAN 2
Customer PremisesSites B
Customer PremisesSites C
Switched Ethernet network with MSTP blocking traffic on a per-VLAN basis
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VLAN Example
Provider uses VLAN tags to identify customer/service
Limit of 4095 services that can be offered
What if the customer wants to use VLANs also?...
Customer 1Site A
Customer 1Site B
Customer 1Site C
MENCustomer 2
Site A
Customer 2Site B
Service 1 (VLAN 100)
Service 2 (VLAN 140)
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Switched Ethernet Scalability Issues
Scale
Limited VLAN space
Upper limit of 4095 service instances
MAC addresses scaling
Example
2000 service instances (customers)
4 sites per customer
200 MAC addresses per customer site
Convergence increases exponentially
with number of meshed network devices
Spanning Tree Convergence
0
1
2
3
4
5
6
7
8
9
2 3 4 5 6 7 8 9 10 11
Nodes
Tim
e in
se
cs
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802.1ad:: Provider Bridge (Q-in-Q) 802.1ad provides a mechanism to encapsulate customer
VLANs inside of provider VLANs (Q-in-Q)
Ethernet
ServiceVLAN
Customer VLAN
ServiceVLAN
Customer VLAN
Customer VLAN
Customer VLAN
MAC Dst MAC Src Service Tag Customer Tag
User Data
MAC Dst MAC Src Customer Tag
User Data
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802.1ah:: PBB (Mac-in-Mac) Even with Q-in-Q, still limited to 4095
services per network
Addressed by 802.1ah – Provider Backbone Bridges
Defines MAC-in-MAC frame format with increase in scalability to 2^24 service instances
Backbone MAC header which encapsulates entire customer MAC header and payload
Backbone bridges only learn MACs of other backbone bridges
User Data
C-VID
S-VID
C-DA
C-SA
I-SID
B-VID
B-DA
B-SA
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802.1ah:: PBB (Mac-in-Mac) 802.1ah provides a mechanism to encapsulate customer
frames inside of provider frames (MAC-in-MAC)
C-DA C-SA S-VID C-VID User Data
BackboneEthernet
B-DA B-SA B-VID I-SID
B-Bone VLAN / Service Instance
B-Bone VLAN / Service Instance
CustomerEther
ServiceVLAN Customer VLAN
ServiceVLAN
Customer VLAN
Customer VLAN
Customer VLAN
ServiceVLAN
Customer VLAN
Customer VLAN
CustomerEther
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Example of PB and PBB Format:: 802.1Q 802.1ad 802.1ah
Source: Ericsson Review No. 3 2007, “Carrier Ethernet: The native approach”
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PBBN Defined in 802.1ah:: Provider Backbone Bridged Network
Source: IEEE 802-1ah-D4.0
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More Refinement For Ethernet
Connectionless approach provides simplicity in small networks Unknown destination addresses are “learned” by broadcasting then
observing
Simplifies implementation and administration
Duplicate paths to destination resolved by running spanning tree
…but becomes a liability in larger metro networks Broadcast traffic consumes valuable bandwidth
Spanning tree provides resiliency but is too slow
Inability to engineer the network for efficiency and deterministic behavior
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More Refinement For Ethernet Cont… Solution
Turn off flooding
Eliminate spanning tree
Allow Ethernet “tunnels” to be created, thereby enabling traffic engineering
Provide fast failure restoration using back-up “tunnels” or paths
Two emerging solutions: PBB-TE and T-MPLS PBB-TE (Traffic Engineering), similar to Nortel PBT
PBT is a technology originated by Nortel; now a working group item at IEEE – 802.1Qay
T-MPLS (Transport MPLS) Standards and drafts in ITU-T Study Group 15
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PBB-TE (PBT) Overview
PBB-TE
Provider Backbone Bridging – Traffic Engineering
Work started by IEEE in March ’07
Based on PBT – Provider Backbone Transport
Uses statically configured tunnels
Works by forwarding on the Backbone MAC DA and VID (together create globally unique ID)
Point-to-Point only
Forwarding tables are currently populated by out-of-band management system
Back-up tunnels can be configured and failure detection provided by ETH-CCs transmitted at high rate
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PBB-TE (PBT) Overview Cont…
Copyright Spirent; portions MEF Page 75
PBB-TE (PBT) Overview
Input B-DA Input B-VID Output Port
00:10:94:00:00:02 124 3
00:10:94:10:00:05 505 15
00:10:94:30:00:05 113 4
00:10:94:20:00:08 743 9
00:10:94:50:00:11 981 1
B-DAB-SAB-VID
C-MAC
User Data
B-DAB-SAB-VID
C-MAC
User Data
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Transport MPLS (T-MPLS)
Connection-oriented packet transport technology based on MPLS frame formats.
Reuses the most widespread label swapping paradigm
Profiles MPLS so that it avoids the complexity and need for IP routing capability
Turns off some MPLS features incompatible with OAM
PHP – penultimate hop pop
Connectionless forwarding
Most IP capability & LSP Merge
Defines OAM capabilities that enable status & performance report
Does not require deeper packet inspection
Allows for guaranteed SLAs
Defines protection switching and restoration
Fault localization and multi-operator service offering
Operated with network management and/or by a control plane
The control plane inside the T-MPLS network can be ASON/GMPLS
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T-MPLS Layers
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T-MPLS Standard Roadmap
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Agenda
Carrier Ethernet Overview
MEF’s Service Definition & Certification
Ethernet OAM
Service OAM (a.k.a. CFM, defined in IEEE 802.1ag/ITU-T Y.1731)
Link OAM (a.k.a. EFM, defined in IEEE 802.3ah)
Bridging & Transport Technologies
PB (802.1ad/Q-in-Q), PBB (802.1ah/Mac-in-Mac)
PBB-TE (PBT/802.1Qay), T-MPLS
Testing Carrier Ethernet
Summary
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Typical Carrier Ethernet Device Capability
Device Characteristic Carrier Ethernet
Switch/Router
Customer Service provider
High availability MSTP/RSTP/STP, graceful restart, Fast re-route, PBT fast failover
Routing protocols MPLS/VPLS, OSPF, ISIS, BGP, RIP, multicast routing
Services MEF E-Line, E-LAN, E-Tree, VLAN, L3 VPNs, Ethernet aggregation (PPPoE/PON)
Service Instances Several thousand
Bridging 802.1Q, 802.1ad, 802.1ah, PBT
OAM 802.3ah, 802.1ag/Y.1731
Traffic shaping/policing Per EVC
SLAs With guaranteed bandwidth, frame latency, jitter, loss ratio per service instance
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Carrier Ethernet Service:: Testing Points
SLA/QoS
Verifying SLA/QoS involves advanced performance measurements such as
loss, latency and jitter
Scalability & Performance
“Carrier” grade must scale! – protocol and service scalability
Devices must support thousands of service instances (4k VLANs * 4 priority
levels = 16k unique service levels)
Next-gen devices support thousands of unique service rates per port
Conformance
New services, devices and protocols – conformance testing helps customers
develop and regress their new products!
Copyright Spirent; portions MEF Page 82
EOAM Test Areas
Functional Do all operations perform as required?
Interoperability New specifications, confusion on specification similarities
IEEE vs. ITU-T
Performance Can devices process and react accordingly to thousands of
messages?
What are a device’s limits? Number of MEPs
Number of MAs/MEGs
Supported CC intervals
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PBB-TE & PBT Test Areas
Verify correct encapsulation/de-encapsulation at edges
Measure fast-failover capability
Verify and benchmark frame forwarding behavior
Validate that destination unknown frames are dropped and
not broadcast
Test stability and accuracy with high numbers of backbone
tunnels
Copyright Spirent; portions MEF Page 84
MPLS/VPLS orPBB/PBT/T-MPLS
Examples of Test Scenarios:: Testing Points & Spirent Solutions
Generate and analyze 802.1ad, 802.1ah, T-MPLS, or PBT traffic
Evaluate and validate system performance per-VLAN, stacked VLANs, B-VLAN, etc.
Measure hard QoS per service instance using real time loss, jitter, latency, etc.
Emulate unique Ethernet service subscribers with at least 2000 unique rates per port/stream
Validate protocols such as STP/RSTP/MSTP or VPLS, 802.1ag/Y.1731 and 802.3ah
MEN
LANSTP/RSTP/MSTP
PE/BEB or P/BB Ethernet Switch/Router
Office building w/ MTU
Office building w/ MTU
Corporate LAN
Corporate LAN
Link OAM (802.3ah)
Service OAM (802.1ag/Y.1731)
802.1ad, 802.3 Traffic
LANSTP/RSTP/MSTP
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EOAM Test Example
MIP
MEP
MA_1VID 100
MA_2VID 200
MA_3VID 300
MA_1VID 100
MA_2VID 200
MA_3VID 300
3 MAs with 5 MEPs and 1 MIP in each
Each MA configured to use a different VID
Spirent TestCenter connected to the DUT
with a single GigE interface configured with
3 VLANs
DUT is a MEP in each of the 3 MAs
Copyright Spirent; portions MEF Page 86
…And Growing Complexity!
Copyright Spirent; portions MEF Page 87
Summary Cont…
Copyright Spirent; portions MEF Page 88
Thank You