Metro Ethernet Network

Customer Edge(CE)

User Network Interface (UNI)

User Network Interface (UNI)

Customer Edge(CE)

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Ethernet Virtual Connection (EVC) defined An EVC is an instance of an association of 2 or more UNIsEVCs help visualize the Ethernet connectionsLike Frame Relay and ATM PVCs or SVCsCannot leak frame from one EVC to anotherMEF has defined 2 EVC typesPoint-to-PointEVCs define the service connectivityMENMultipoint-to-Multipoint EVC

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Service Types defined in MEF 6E-Line Service used to createEthernet Private LinesVirtual Private LinesEthernet Internet AccessPoint-to-Point upper layer services transport (IP-VPNs etc) E-LAN Service used to createMultipoint L2 VPNsTransparent LAN ServiceMulticast networksCECEPoint-to-Point EVCMENUNIUNIE-Line Service typeCECECEMENCEMultipoint-to-Multipoint EVCUNIUNIUNIUNIE-LAN Service type

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Example Service using E-Line Service TypeEthernet Private LineReplaces a TDM Private lineDedicated UNIs for Point-to-Point connectionsSingle Ethernet Virtual Connection (EVC) per UNIMENEthernet UNIEthernet UNIEthernet UNIPoint-to-Point EVC CEEthernet Private Line using E-Line Service typeInternetISPPOPStorage SPEthernet UNICECE

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Example Service using E-Line Service TypeEthernet Virtual Private LineReplaces Frame Relay or ATM servicesSupports Service Multiplexed UNI*Allows single physical connection to customer premise equipment for multiple virtual connectionsCECEMENEthernet UNIEthernet UNIService Multiplexed Ethernet UNIMultiple Point-to-Point EVCsCEEthernet Virtual Private Line using E-Line Service type* This is a UNI that must be configurable to support Multiple EVCs per UNI

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Example Service using E-LAN Service TypeTransparent LAN Service (TLS) providesMultipoint-multipointIntra-company ConnectivityFull transparency of control protocols (BPDUs)New VLANs addedwithout coordination with providerMultipoint-to-Multipoint EVCUNI 1UNI 3UNI 4UNI 2MENVLANsEngineeringVLANsSalesCustomer ServiceEngineeringVLANsSalesVLANsSalesCustomer ServiceTLS makes the MEN look like a LANTransparent LAN Service

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Example Service using E-LAN Service TypeEthernet MulticastPoint to multipoint for broadcast applications (Video)Supports Service Multiplexed UNI (to deliver multiple channels)

CECEMENEthernet UNIEthernet UNIService Multiplexed Ethernet UNIPoint-to-multipoint EVCsCEEthernet Delivery of Multicast IPTV Traffic

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Ethernet Frame handlingMEF 10 Defines how the services should handle customer generated frames Service framesCustomer VLANsMEF 10 defines how to establish traffic classes and the required traffic management

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Delivery of Service FramesBroadcastDeliver to all UNIs in the EVC but the ingress UNIMulticastTypically delivered to all UNIs in the EVC but the ingress UNIUnicast (unlearned and learned)Typically delivered to all UNIs in the EVC but the ingress UNI if not learnedOtherwise, deliver to the UNI learned for the destination MAC addressLearning is important for Multipoint-to-Multipoint EVCsLayer 2 Control (e.g., BPDU)Discard, peer, or tunnel

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Options for Layer 2 Control ProtocolsDiscardPDU from CE discarded by MENPDU never egresses from MENPeerMEN peers with CE to run protocolTunnelPDUs carried across MEN as if they were normal dataEVC is that associated with the Customer Edge VLAN ID (CE-VLAN ID) of the PDU, e.g., the Untagged CE-VLAN ID for most standard Layer 2 Control Protocols defined by IEEE 802

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CE-VLAN ID Preservation/MappingCE-VLAN ID 37EVC BlueCE-VLAN ID 37EVC BlueCE-VLAN ID/EVC Map must be identical at all UNIs in the EVC andPriority Tagged in must be priority tagged outUntagged in must be untagged outPreserve CustomerVLANs

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All to One Bundling (Map)CE-VLAN ID 1 2 . . . 4094 4095EVC RedCE-VLAN ID/EVC MapOnly one EVC at the UNI (no service multiplexing)All CE-VLAN IDs map to this EVC no need for coordination of CE-VLAN ID/EVC Map between Subscriber and Service ProviderEVC must have CE-VLAN ID Preservation

Untagged* Priority Tagged* Tagged, VID = 1 Tagged, VID = 2 . . . Tagged, VID = 4094 Tagged, VID = 4095Send all CustomerVLANs

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Using All to One BundlingCE Bridge or RouterLAN Extension EVCHQBranchBranchSimplified BranchLAN extension Set-up

- No VLAN Mapping- No VLAN preservationCustomer VLAN 6,7,9VLAN 6,9VLAN 6,7VLAN 6Branch

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One to One MapCE-VLAN ID 1 2 . . . 4094 4095EVC Red BlueCE-VLAN ID/EVC MapNo more than one CE-VLAN ID is mapped to each EVC at the UNIIf CE-VLAN ID not mapped to EVC, ingress Service Frames with that CE-VLAN ID are discardedService Multiplexing possibleCE-VLAN ID Preservation not requiredSubscriber and Service Provider must coordinate CE-VLAN ID/EVC Map

Untagged Priority Tagged Tagged, VID = 1 Tagged, VID = 2 . . . Tagged, VID = 4094 Tagged, VID = 4095

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CE-VLAN ID TranslationCE-VLAN ID 37EVC BlueCE-VLAN ID 156EVC BlueCE-VLAN ID/EVC Map can be different at different UNIs in an EVCFine for CE routersProblematic for CE bridges

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Identifying an EVC at a UNIService Frame FormatUntagged* Priority Tagged* Tagged, VID = 1 Tagged, VID = 2 . . . Tagged, VID = 4094 Tagged, VID = 4095CE-VLAN ID 1 2 . . . 4094 4095EVC Red Green . . . BlueCE-VLAN ID/EVC Map*Untagged and Priority Tagged Service Frames have the same CE-VLAN ID and that value is configurable at each UNI. This is the behavior expected by an IEEE 802.1Q CE.CE-VLAN ID/EVC Map

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Using One to One Map w/ Translation 1CE RouterFrame Relay PVC ReplacementISP Customer 1Internet Service ProviderISP Customer 2ISP Customer 3CE-VLAN ID Preservation would constrain ISP2000 Blue2000 Yellow2000 Green178 Blue 179 Yellow 180 Green}Pt to Pt EVCs

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Using One to One Map 2CE RouterMultipoint-to-Multipoint EVCsASP Customer 1ASP Customer 2ASP Customer 3ASPASPASP Customer 3

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Industry Service RequirementsIf the services are to be adopted in the market:They require strong service attributesWith meaningful and measurable parameters on which to base the SLA Specification

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The best of all worldsOffer a mix of SLA ensured and non SLA traffic over the same shared MEN access/backbone links.Allow certain traffic be delivered with strict SLAs,Allow other traffic to be delivered best efforts.Critical SLA Service AttributesBandwidth ProfileService Performance

Allows bandwidth to exceed commitments but does not apply SLA conformance measures to that traffic

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How to classify the trafficApply ingress bandwidth profilesAt the UNI (MEF 10) or other NNI handoffs (future)Traffic the meets the profile is marked (colored) in accordance with the SLA commitments.Traffic that meets the profile is marked (colored) subject to the SLA conformance measuresTraffic that does not meet the profile is not subject to the SLA commitments

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Coloring Classified TrafficMEF 10 Specifies coloring of traffic as an optional means to mark traffic as in or out of profile as it leaves the ingress UNIMEF 10 specifies three levels of Bandwidth Profile complianceGreen: Service Frame subject to SLAYellow: Service Frame not subject to SLARed: Service Frame discarded.

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Bandwidth Profiles defined in MEF 10MEF has defined three bandwidth profilesIngress Bandwidth Profile Per Ingress UNIIngress Bandwidth Profile Per EVCIngress Bandwidth Profile Per CoS ID 4 main parameters CIR/CBS determines frame delivery per service level objectivesEIR/EBS determines amount of excess frame delivery allowedCIR/EIR is measure in bits per second , CBS/EBS in Bytes per second

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CIR vs. EIR service exampleConceptual Example3 EVCs share fixed UNI bandwidth3 CIRs can always be met3 EIRs can not always be assured (simultaneously)CIREIRCIREIRCIREIRTotal Bandwidth at UNIEVC1EVC2EVC3Traffic Passed at CIR rates are subject to SLA conformance - if other parameters also metEIR traffic is marked yellow not subject to SLA

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CBS vs. EBSBurst size in Bytes per second allowedCBS marked Green, EBS is Yellow, Bursts beyond EBS limit is discardedBytesTimeData flowBurst ThresholdY Y YCBSlimitEBS

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Bandwidth Profile Defined by Token Bucket Algorithm (2 rates, 3 colors)C-BucketGreen TokensE-BucketYellow TokensOverflowOverflowColor Blind Algorithm Skeleton:If (Service Frame length is less than C-Bucket tokens) {declare green; remove tokens from C-Bucket}else if (Service Frame length is less than E-Bucket tokens){declare yellow; remove tokens from E-Bucket}else declare redCommitted Information Rate (CIR)Excess Information Rate (EIR)Committed Burst Size (CBS)Excess Burst Size (EBS)

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Three Types of Bandwidth Profiles defined in MEF 10UNIEVC1EVC2EVC3Ingress Bandwidth Profile Per Ingress UNIUNIEVC1EVC2EVC3Ingress Bandwidth Profile Per EVC1Ingress Bandwidth Profile Per EVC2Ingress Bandwidth Profile Per EVC3UNIEVC1CE-VLAN CoS 6Ingress Bandwidth Profile Per CoS ID 6CE-VLAN CoS 4CE-VLAN CoS 2Ingress Bandwidth Profile Per CoS ID 4Ingress Bandwidth Profile Per CoS ID 2EVC21) At the UNI level2) At the EVC level3) At the CE-VLAN level

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Two Ways to Identify CoS InstanceEVCAll Service Frames mapped to the same EVC receive the same CoS

All Service Frames mapped to an EVC with one of a set of user_priority values receive the same CoS

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Service Performance (QoS) defined in MEF 10SLA Specification: Service performance parametersFrame delay (one-way delay)Frame delay variation (jitter)Frame lossService performance level to delivery determined via: Bandwidth profile conformanceUNI, EVC or CoS-ID

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Frame Delay and Delay VariationFrame DelayThis is measured as the time taken for service frames across the networkFrame Delay is measured from the arrival of the first bit at the ingress UNI to the output of the last bit of the egress UNI. I.e. an end-to-end measurement as the customer views it.

Frame Delay VariationFrame Delay Variation is therefore the variation in this delay for a number of frames. This delay is an important factor in the transmission of unbuffered video and where variation occurs in the millisecond range can affect voice quality. For data can cause a number of undesirable effects such as perceived frame loss, etcNote: The term Jitter is not an appropriate term to be substituted from Frame Delay VariationNote: The MEF expresses performance of delay and delay variation in percentage termsNote: For most purposes one way delay (rather than round trip delay) is required to establish service quality

Metro Ethernet Network

UNI to UNI

first bit in

last bit out

time

CE

CE

FrameDelay

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Frame Loss DefinedFrame loss is a measure of the number of lost service frames inside the MEN. Frame loss ratio is % = # frames lost / # frames sentMetro Ethernet Metro Ethernet NetworkNetworkUNI to UNIUNI to UNI5000 frames inCECECECE4995 frames outtime5 frames lost/or received as errored0.1% Frame Loss Ratio (5/5000)

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Example CoS-based Metro Ethernet SLAE-Line Virtual Private Line Service4 Classes of ServiceCoS determined via 802.1p CoS IDCommon type of SLA used with CoS-based IP VPNs

Service ClassService CharacteristicsCoS IDBandwidth Profile per EVC per CoS IDService PerformancePremiumReal-time IP telephony or IP video applications6, 7CIR > 0EIR = 0Delay < 5msJitter < 1msLoss < 0.001%SilverBursty mission critical data applications requiring low loss and delay (e.g., Storage)4, 5CIR > 0EIR UNI SpeedDelay < 5msJitter = N/SLoss < 0.01%BronzeBursty data applications requiring bandwidth assurances3, 4CIR > 0EIR UNI SpeedDelay < 15msJitter = N/SLoss < 0.1%StandardBest effort service0, 1, 2CIR=0 EIR=UNI speedDelay < 30msJitter = N/SLoss < 0.5%

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Final WordService Attributes & Parameters Ethernet Private Line, Ethernet Virtual Private Line, Ethernet LAN attributes and parameters are covered in detail in the specifications

Next ActionsAfter reading this document you should now be familiar with the main concepts of Ethernet Services and be in a position to follow the details contained in both the MEF and MEF 10 Specifications

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For Full Details Service Provider 1Metro Ethernet NetworkService Provider 2Metro Ethernet NetworkInternet Global/NationalCarrierEthernetMetroCarrierEthernetAccessCarrierEthernetHosts, Legacy Services, Remote Subscribers etc visit www.metroethernetforum.orgto access the full specification

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This slide deck highlights key recommendations and requirements as defined in the MEF 6 and MEF 10 specifications.It leverages the Ethernet services model and terminology as defined in MEF 10 as well as the Metro Ethernet Network Architecture concepts further defined in MEF 4. The service Definitions and concepts covered in the first half of the deck are outlined in greater detail within MEF 6. The traffic classification and traffic profile concepts are detailed in MEF 10 in greater detail. This deck also summarizes the MEF 10 defined attributes and parameter requirements/recommendations for each MEF 6 defined service type.

*Ethernet Services Model Defined nomenclature

*Ethernet virtual circuit connection defined.

EVCs are service connections between UNIs.conceptually equivalent to Virtual Circuits defined by the ATM and Frame Relay forums

Multi-point EVCs are a new concept where an EVC can be established between more than two UNIs*There are two Major Service types defined in MEF 6. Point to point Ethernet services know as E-Line, and Multipoint to Multipoint service know as E-LAN.

Note we will define to different types of E-Line services, Ethernet Private Line (EPL) and Ethernet Virtual Private Line in detail*Ethernet Private Line Service is mean to have similar attributes and characteristics as todays traditional TDM based Private lines. The concept is to support the natural migration of TDM private Lines to higher rate Ethernet based private lines.*Ethernet Virtual Private Line Service is mean to have similar attributes and characteristics as todays traditional Frame Relay or ATM based virtual private lines. The concept is to support the natural migration of Frame Relay and ATM virtual circuit based services to higher rate Ethernet based virtual circuit services.

*E-LAN is a new service which allows a single Virtual Circuit to provide connectivity to multiple sites. It allows the Metro Ethernet Network to act like an extension of the connectionless corporate LANs across the service provider network*E-LAN services can also be used for new service applications such as the efficient transport of Broadcast and multicast traffic to a large number of end points. In this example we illustrate its use in supporting IPTV from a content head0end out to individual customers. There can be many more applications, yet to be fully defined, but the intent is to allow the E-LAN to be specified loosely enough to account for as many as possibleallowing for greater detail to be defined as required in subsequent specification work.*MEF 10 details how to implement the services defined in MEF 6. It starts with requirements and recommendations of how the MEN should handle each type of customer generated Ethernet frame. It then defines how to map the customer traffic to EVCs, establish traffic classes or profiles, and then how to apply and measure QoS parameters for the classified traffic to support Service Level Objectives (SLOs).*Service frames are defined asBroadcast, Multicast, Unicast, frames as generated by the customer. MEF 10 defines their treatment for each service type defined in MEF 6

*Options for handling of L2 control protocols as defined in MEF 10.*In order to allow the appropriate (Desired) connectivity across the MEN certain concepts and procedures are defined.

This includes the concept of Customer VLAN preservation. This allows for transparent connectivity services to be set-up across the providers network*All to one Bundling is typically defined for Ethernet Private Line applications or dedicated access (such as to a VPN service), or for extending LANs between multiple remote sites.

This makes set-up of circuits simple as well as ensuring all traffic that enters a EP ingress - properly egresses at the other side*This is an example of using All to one bundling in an E-LAN. The HQ has three separate LANs that need to be extended to the remote sites. In this case they can all share a single EVC. The customer routers at each site deliver the frames as appropriate and discard other not intended for that site.**CE-VLAN ID Translation is important for applications where service is handed off to a third partysuch as an ISP, VPN provider who has many customers hat need to have traffic kept separate and may have overlapping VLAN address space. The next slide shows an example how VLAN translation will support Ethernet access networks that are served by frame Relay today**Mapping with translation helps enable Frame Relay replacement by point to point Ethernet services*Multipoint Ethernet services open more cost effective new multi-site services. In this case the SAME mapped and translated EVC can support multiple sites (not possible with Frame Relay or ATM).*MEF 10 defines the concept of Service attributes and parameters. MEF 6 helps establish what those attributes are for each service type.*The Promise of Ethernet services are the mix of connectivity options and the pay for value granularity not allowed with todays more limited choices. - End customers will pay for value if it can be meaningfully be demonstrated ( measured and evaluated).- Service providers can charge more per bit - for a lower transported bit cost if they can optimize the service mix across their shared service MEN.

Both of these concepts require the ability to support transporting a mix of services with verifiable SLOs over a single network.*MEF 6 defines the concept that traffic be classified at the UNI hand-off as it enters the MEN. Separate profiles can be set-up for different handling by the network. MEF 10 defines how that traffic that meets a profile will be handled to meet a defined SLA. It also allows for handling traffic that exceeds the profile and can be transported at best efforts (without SLA conformance measures applied).

To do this MEF 10 defines how traffic frames can be marked (colored) in profile and out of profile for further treatment at other nodes through the MEN. Coloring allows for detecting which frames should be subject to SLA conformance testing upon MEN network egress.*Coloring is optional, but is an important concept for supporting value added capabilities such as bursting over Ethernet Virtual Private Lines services. It allows for handling a flexible mix of traffic from the same customer and still maintain a sound basis for applying and measuring SLAs.*Bandwidth profiles can be applied per UNI (all traffic regardless of VLAN tag or EVC ID)or more granular on an EVC basis or even a COS marking such as a customer applied VLAN priority tag).

The parameters are similar in concept to those defined for Frame RelayCommitted rates and excess rates in bits per second. For bursting a burst size buffer allocation can also be specified - in bytes per second. *This slide provides a conceptual example of CIR vs EIR where multiple EVCs share the SAME UNI, or transport line.Service example - comparing CIR conformance marked traffic vs. EIR conformance marked traffic:CIR conforming traffic can be marked green, indicating it should be measured upon egress to determine if the traffic is within the Service level objective agreed upon parameters. Traffic that exceeds the CIR is Marked yellow and is not subject to the SLA, hence is not measured at network egress.

Traffic that exceeds the EIR is discarded.*The diagram in this slide attempts to depict these bursting concepts as specified in MEF 10Bursting parameters indicate the amount of bytes that can be accepted over a sustained period at the point of measurement. Buffer capacity (typically at the MEN UNI demark) may be allocated in byte thresholds as committed burst size (CBS) and excess burst size (EBS). Frames arriving within the CBS parameter can be marked green and passed into the MEN for subsequent egress SLA conformance measurement. Frames burst beyond the CBS time interval but within the EBS time interval can be marked yellow and passed, but will not be subject to egress SLA conformance measurement. Frames burst beyond the EBS threshold time limit will be dropped.

*The MEF has defined a dual leaky bucket algorithm to assist consistent implementation of CIR/EIR/CBS/EBS measurements and marking.*The Profiles can be at the UNI, or within the UNI at the individual EVC level, or Within the EVC at the Individual CE-VLAN Class of service (Customer marked frame) level.*COS can be applied at the EVC level (same COS for all frames transmitted over the EVC), or can be applied within the EVC by customer defined priority values in the data such as CE-VLAN IEEE 802.3 Q or p tag markings.*MEF 10 not only defines how to classify ingress traffic for different treatment, it also defines how to measure QoS on the classified (conforming traffic) traffic.

Three QoS SLA service conformance parameters have been defined.One way frame delayFrame delay variation (jitter)And the frame loss ratio*Frame Delay variation depicts the difference in time gap between two subsequent frames at the ingress UNI in comparison to the delay measured between the arrival of the same frames at the egress UNI.*Frame loss is measured as a ratio of the number of frames lost (lost or discarded at egress due to FCS indicated error) measured at the Egress UNI divided by the number of frames sent as measured at the ingress UNI.

Note E-LAN service frame loss ratio measures are left for further study*Applying the methods as defined in MEF 10 to a E-Line Virtual Private Line service example as defined in MEF 6.*This section goes into further detail in detailing the defined Service Attributes and parameters requirement and recommendations as specified for each of the defined services: EPL, EVPL and E-LAN.

(Refer to the Specs and the accompanying Ethernet Service Description document for more details)

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