1 Metro Ethernet Forum Layer 2 Services Bob Klessig Member of the Board and Co-Chair of the...

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Metro Ethernet Forum Layer 2 Metro Ethernet Forum Layer 2 ServicesServices

Bob KlessigBob KlessigMember of the Board and Co-Chair of the Member of the Board and Co-Chair of the

Technical CommitteeTechnical Committee

Director of Engineering, Cisco SystemsDirector of Engineering, Cisco [email protected]@cisco.com

22

AgendaAgenda

• MEF Specifications RoadmapMEF Specifications Roadmap

• Services ModelServices Model

• Traffic ManagementTraffic Management

33

MEF Services Technical MEF Services Technical SpecificationsSpecifications

MEF 1.0MEF 1.0Ethernet Services Model, Phase1*Ethernet Services Model, Phase1*

Technical descriptions of service featuresTechnical descriptions of service features

*http://www.metroethernetforum.org/PDFs/Standards/MEF-1.0.doc*http://www.metroethernetforum.org/PDFs/Standards/MEF-1.0.doc

MEF x.0MEF x.0Traffic Management Specification, Phase1Traffic Management Specification, Phase1

Fractional Bandwidth and PerformanceFractional Bandwidth and Performance

MEF x.0MEF x.0Ethernet Services Definitions, Phase1Ethernet Services Definitions, Phase1

Specific service instancesSpecific service instances

44

AgendaAgenda

• MEF Specifications RoadmapMEF Specifications Roadmap



55

Services ModelServices Model

MetroMetroEthernetEthernetNetworkNetwork

CustomerCustomerEdge (e.g., router)Edge (e.g., router)

(CE)(CE)

CustomerCustomerEdgeEdge(CE)(CE)

ServiceServiceAttributesAttributes

A service is what the CE sees.A service is what the CE sees.The technology used inside the MEN is not visible.The technology used inside the MEN is not visible.

66

User Network InterfaceUser Network Interface

MetroMetroEthernetEthernetNetworkNetwork

CECE CECE

The demarcation point between Service The demarcation point between Service Provider and Subscriber ResponsibilitiesProvider and Subscriber Responsibilities

UNIUNI UNIUNI

• Dedicated to a single SubscriberDedicated to a single Subscriber• Based on Standard Ethernet PHYs for Phase 1, e.g.,Based on Standard Ethernet PHYs for Phase 1, e.g.,

– RJ45 Socket on Service Provider owned Ethernet switchRJ45 Socket on Service Provider owned Ethernet switch– RJ45 plug on Service Provider owned cableRJ45 plug on Service Provider owned cable

77

Service FrameService Frame

• The Layer 2 protocol data unit exchanged The Layer 2 protocol data unit exchanged between the CE and the MEN at the UNIbetween the CE and the MEN at the UNI

• Standard EthernetStandard Ethernet– With IEEE 802.1Q tag (up to 1522 bytes)With IEEE 802.1Q tag (up to 1522 bytes)– Without IEEE 802.1Q tag (up to 1518 bytes)Without IEEE 802.1Q tag (up to 1518 bytes)– Includes everything but the preambleIncludes everything but the preamble

• More than 100 Million devices exist that More than 100 Million devices exist that are potential Customer Edge devicesare potential Customer Edge devices

88

Service Frame TransparencyService Frame TransparencyService Frames must be delivered from ingress UNI to Service Frames must be delivered from ingress UNI to egress UNI(s) transparently except possibly as follows:egress UNI(s) transparently except possibly as follows:

Ingress Service FrameIngress Service Frame Egress Service Frame*Egress Service Frame*

UntaggedUntagged TaggedTagged

TaggedTagged UntaggedUntagged

TaggedTagged Tagged w/ different valueTagged w/ different value

*Frame Check Sequence recalculated*Frame Check Sequence recalculated

99

Each Service Instance is a Layer 2 Each Service Instance is a Layer 2 VPNVPN

• Service Frames cannot leak in or out of a Service InstanceService Frames cannot leak in or out of a Service Instance

• Multiple Service instances can exist at a UNI, called Service Multiple Service instances can exist at a UNI, called Service MultiplexingMultiplexing

Example showing a green serviceExample showing a green serviceand a blue service.and a blue service.

ServiceServiceMultiplexed UNIMultiplexed UNI

1010

Formal Service Instance Formal Service Instance DefinitionDefinition

• Association of two or more UNIsAssociation of two or more UNIs

• Service Frames can only be exchanged Service Frames can only be exchanged among the associated UNIsamong the associated UNIs

• A Service Frame sent into the MEN via a A Service Frame sent into the MEN via a particular UNI MUST NOT be delivered particular UNI MUST NOT be delivered out of the MEN via that UNIout of the MEN via that UNI

Ethernet Virtual Connection (EVC)Ethernet Virtual Connection (EVC)

1111

Point-to-Point EVCPoint-to-Point EVC

Exactly two UNIs are associated.Exactly two UNIs are associated.

1212

Multipoint-to-Multipoint EVCMultipoint-to-Multipoint EVC

• Two* or more UNIs are associatedTwo* or more UNIs are associated

• A broadcast or multicast ingress frame is typically A broadcast or multicast ingress frame is typically replicated and delivered to all of the other UNIsreplicated and delivered to all of the other UNIs

* A MP2MP EVC with two UNIs is different than a P2P EVC since additional UNIs * A MP2MP EVC with two UNIs is different than a P2P EVC since additional UNIs can be added at any time.can be added at any time.

1313

Identifying an EVC at a UNIIdentifying an EVC at a UNI

Service Frame FormatService Frame Format

Untagged*Untagged*Priority Tagged*Priority Tagged*Tagged, VID = 1Tagged, VID = 1Tagged, VID = 2Tagged, VID = 2

..

..

..Tagged, VID = 4094Tagged, VID = 4094Tagged, VID = 4095Tagged, VID = 4095

CE-VLAN IDCE-VLAN ID

1122......

4094409440954095

EVCEVC

RedRedGreenGreen

..

..

..BlueBlue

CE-VLAN ID/EVC MapCE-VLAN ID/EVC Map

*Untagged and Priority Tagged Service Frames have the same CE-VLAN ID and that *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.value is configurable at each UNI. This is the behavior expected by an IEEE 802.1Q CE.


1414

CE-VLAN ID PreservationCE-VLAN ID Preservation

CE-VLAN IDCE-VLAN ID3737

EVCEVCBlueBlue


EVCEVCBlueBlue

CE-VLAN ID/EVC Map for EVC must be identical at all CE-VLAN ID/EVC Map for EVC must be identical at all UNIs in the EVC andUNIs in the EVC and

• Priority Tagged in must be priority tagged outPriority Tagged in must be priority tagged out

• Untagged in must be untagged outUntagged in must be untagged out

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All to One Bundling (Map)All to One Bundling (Map)CE-VLAN IDCE-VLAN ID

1122......

4094409440954095

EVCEVC

RedRed


• Only one EVC at the UNI (no service multiplexing)Only one EVC at the UNI (no service multiplexing)• All CE-VLAN IDs map to this EVC – no need for coordination of All CE-VLAN IDs map to this EVC – no need for coordination of

CE-VLAN ID/EVC Map between Subscriber and Service ProviderCE-VLAN ID/EVC Map between Subscriber and Service Provider• EVC must have CE-VLAN ID PreservationEVC must have CE-VLAN ID Preservation


..

..


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Using All to One BundlingUsing All to One Bundling

BridgeBridgeor Routeror Router

Private LinePrivate LineReplacementReplacement

LANLANExtensionExtension

HQHQ BranchBranch

BranchBranch

Disaster RecoveryDisaster RecoveryService ProviderService Provider

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One to One MapOne to One MapCE-VLAN IDCE-VLAN ID

1122......

4094409440954095

EVCEVC

RedRedBlueBlue

CE-VLAN ID/EVC MapCE-VLAN ID/EVC Map• No more than one CE-VLAN ID is mapped to each EVC at the UNINo more than one CE-VLAN ID is mapped to each EVC at the UNI

• If CE-VLAN ID not mapped to EVC, ingress Service Frames with that CE-If CE-VLAN ID not mapped to EVC, ingress Service Frames with that CE-VLAN ID are discardedVLAN ID are discarded

• Service Multiplexing possibleService Multiplexing possible

• CE-VLAN ID Preservation not requiredCE-VLAN ID Preservation not required

• Subscriber and Service Provider must coordinate CE-VLAN ID/EVC Map Subscriber and Service Provider must coordinate CE-VLAN ID/EVC Map

UntaggedUntaggedPriority TaggedPriority TaggedTagged, VID = 1Tagged, VID = 1Tagged, VID = 2Tagged, VID = 2

..

..


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CE-VLAN ID TranslationCE-VLAN ID Translation


EVCEVCBlueBlue


EVCEVCBlueBlue

CE-VLAN ID/EVC Map can be different at different UNIs in an EVCCE-VLAN ID/EVC Map can be different at different UNIs in an EVC

• Fine for CE routersFine for CE routers

• Problematic for CE bridgesProblematic for CE bridges

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Using One to One MapUsing One to One Map

RouterRouterFrame Relay PVCFrame Relay PVC

ReplacementReplacement

ISPISPCustomer 1Customer 1

InternetInternetService ProviderService Provider



CE-VLAN ID PreservationCE-VLAN ID Preservationwould constrain ISPwould constrain ISP

2000 2000 Blue Blue 2000 2000 Yellow Yellow

2000 2000 Green Green

178 178 Blue Blue179 179 Yellow Yellow180 180 Green Green

2020

Bundling (Map)Bundling (Map)CE-VLAN IDCE-VLAN ID

112233....

4094409440954095

EVCEVC

RedRedBlueBlue


• More than one CE-VLAN ID is mapped to an EVC at the UNIMore than one CE-VLAN ID is mapped to an EVC at the UNI

• Service Multiplexing possibleService Multiplexing possible

• CE-VLAN ID Preservation is required for EVC if multiple CE-VLAN CE-VLAN ID Preservation is required for EVC if multiple CE-VLAN IDs mapped to itIDs mapped to it

• Subscriber and Service Provider must coordinate CE-VLAN ID/EVC Subscriber and Service Provider must coordinate CE-VLAN ID/EVC MapMap


..

..


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Ethernet LAN ServiceEthernet LAN Service(E-LAN)(E-LAN)

Ethernet Line ServiceEthernet Line Service(E-Line)(E-Line)

Feature Combinations and UsesFeature Combinations and Uses

CE-VLAN ID/EVC CE-VLAN ID/EVC Map CharacteristicMap Characteristic

EVC TypeEVC Type

Point-to-PointPoint-to-Point Multipoint-to-MultipointMultipoint-to-Multipoint

All to One BundlingAll to One BundlingPrivate Line replacement Private Line replacement with Router or Bridgewith Router or Bridge

LAN Extension with LAN Extension with Router or BridgeRouter or Bridge

One to One MapOne to One MapFrame Relay replacement Frame Relay replacement with Routerwith Router

Uses TBDUses TBD

BundlingBundling Uses TBDUses TBD Uses TBDUses TBD

2222

Delivery of Service FramesDelivery of Service Frames

• BroadcastBroadcast– Deliver to all UNIs in the EVC but the ingress UNIDeliver to all UNIs in the EVC but the ingress UNI

• MulticastMulticast– Typically delivered to all UNIs in the EVC but the ingress Typically delivered to all UNIs in the EVC but the ingress

UNIUNI• UnicastUnicast

– Typically delivered to all UNIs in the EVC but the ingress Typically delivered to all UNIs in the EVC but the ingress UNI if not learnedUNI if not learned

– Otherwise, deliver to the UNI learned for the destination Otherwise, deliver to the UNI learned for the destination MAC addressMAC address

– Learning is important for Multipoint-to-Multipoint EVCsLearning is important for Multipoint-to-Multipoint EVCs• Type of Service Frame determined from the Type of Service Frame determined from the

destination MAC addressdestination MAC address

2323

Handling Layer 2 Control ProtocolsHandling Layer 2 Control Protocols

BridgeBridge

BridgeBridgeBridgeBridge

• Bridges will try to run Spanning Tree Protocol by exchanging Bridge Bridges will try to run Spanning Tree Protocol by exchanging Bridge Protocol Data Units (BPDUs)Protocol Data Units (BPDUs)

• If BPDUs are blocked, loop will result and Ethernet Service will be unusableIf BPDUs are blocked, loop will result and Ethernet Service will be unusable

• Solutions: Use routers or deliver Subscriber BPDUsSolutions: Use routers or deliver Subscriber BPDUs

Need to worry about Layer 2 Control ProtocolsNeed to worry about Layer 2 Control Protocols

BridgingBridgingExampleExample

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Options for Layer 2 Control Options for Layer 2 Control ProtocolsProtocols

• DiscardDiscard– PDU from CE discarded by MENPDU from CE discarded by MEN– PDU never egresses from MENPDU never egresses from MEN

• PeerPeer– MEN peers with CE to run protocolMEN peers with CE to run protocol

• TunnelTunnel– PDUs carried across MEN as if they were normal dataPDUs carried across MEN as if they were normal data– EVC is that associated with the CE-VLAN ID of the PDU, EVC is that associated with the CE-VLAN ID of the PDU,

e.g., the Untagged CE-VLAN ID for most standard Layer e.g., the Untagged CE-VLAN ID for most standard Layer 2 Control Protocols defined by IEEE 8022 Control Protocols defined by IEEE 802

2525

AgendaAgenda

• Specifications RoadmapSpecifications Roadmap



2626

CaveatCaveat

MEF Traffic Management MEF Traffic Management work is still evolving and work is still evolving and likely to change significantly.likely to change significantly.

2727

Two Areas Covered by Traffic Two Areas Covered by Traffic ManagementManagement

• Bandwidth ProfileBandwidth Profile– How to buy just the bandwidth you need How to buy just the bandwidth you need

and have a predictable billand have a predictable bill

• Class of ServiceClass of Service– Identifying the CoS for a Service FrameIdentifying the CoS for a Service Frame– Performance parameters that define a Performance parameters that define a

CoSCoS

2828

Bandwidth Profile OverviewBandwidth Profile Overview

• Similar in concept to the traffic policing of Frame Similar in concept to the traffic policing of Frame RelayRelay

• Bandwidth Profile is a characterization of the Bandwidth Profile is a characterization of the lengths and arrival times of Service Frames at the lengths and arrival times of Service Frames at the UNIUNI

• The level of compliance with the Bandwidth The level of compliance with the Bandwidth Profile is assessed for each ingress Service Profile is assessed for each ingress Service FrameFrame– Green = full complianceGreen = full compliance– Yellow = partial complianceYellow = partial compliance– Red = non-complianceRed = non-compliance

• Delivery performance then based on compliance Delivery performance then based on compliance levellevel

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Bandwidth Profile Defined by Bandwidth Profile Defined by Token Bucket AlgorithmToken Bucket Algorithm

C-BucketC-Bucket

““Green”Green”TokensTokens

E-BucketE-Bucket

““Yellow”Yellow”TokensTokens

OverflowOverflow OverflowOverflow

If (Service Frame length less than C-Bucket tokens)If (Service Frame length less than C-Bucket tokens)declare green and remove tokens from C-Bucketdeclare green and remove tokens from C-Bucket

else if (Service Frame length less than E-Bucket tokens)else if (Service Frame length less than E-Bucket tokens)declare yellow and remove tokens from E-Bucketdeclare yellow and remove tokens from E-Bucket

else declare redelse declare red

CommittedCommittedInformationInformation

RateRate

ExcessExcessInformationInformation

RateRate

CommittedCommittedBurst SizeBurst Size

ExcessExcessBurst SizeBurst Size

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Two Options for AlgorithmTwo Options for Algorithm

C-BucketC-Bucket


E-BucketE-Bucket


OverflowOverflow

OverflowOverflow

C-BucketC-Bucket


E-BucketE-Bucket


OverflowOverflow

OverflowOverflow

Option 1: DecoupledOption 1: Decoupled Option 2: CoupledOption 2: Coupled

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Bandwidth Profile ParametersBandwidth Profile Parameters

• Committed Information Rate (CIR) Committed Information Rate (CIR) expressed as bits per second. CIR expressed as bits per second. CIR 0. 0.

• Committed Burst Size (CBS) expressed as Committed Burst Size (CBS) expressed as bytes. CBS bytes. CBS 0. 0.

• Excess Information Rate (EIR) expressed Excess Information Rate (EIR) expressed as bits per second. EIR as bits per second. EIR 0 0

• Excess Burst Size (EBS) expressed as Excess Burst Size (EBS) expressed as bytes. EBS bytes. EBS 0. 0.

• Coupling Flag (S). S = 0 or 1. Coupling Flag (S). S = 0 or 1.

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Detailed Algorithm (Extension Detailed Algorithm (Extension of RFC 2697)*of RFC 2697)*

BBcc(t(tjj) = min{CBS, B) = min{CBS, Bcc(t(tj-1j-1) + CIR) + CIR(t(tjj – t – tj-1j-1)})}

B Bee(t(tjj) = min{EBS, B) = min{EBS, Bee(t(tj-1j-1) + EIR) + EIR(t(tjj – t – tj-1j-1) + S) + Smax[0, Bmax[0, Bcc(t(tj-1j-1) + CIR) + CIR(t(tjj – t – tj-1j-1) – CBS]}) – CBS]}

Frame of length lFrame of length ljj arrives at t arrives at tjj

lljj ≤ B≤ Bcc(t(tjj))Declare frame greenDeclare frame green

BBcc(t(tjj) = B) = Bcc(t(tjj) - l) - ljj

lljj ≤ B≤ Bee(t(tjj))Declare frame yellowDeclare frame yellow

BBee(t(tjj) = B) = Bee(t(tjj) - l) - ljj

Declare frame redDeclare frame red

YesYes

YesYesNoNo

NoNo

*Algorithm for “color blind” mode. A “color aware” version exists but requires some way to *Algorithm for “color blind” mode. A “color aware” version exists but requires some way to identify the color of the ingress Service Frame. identify the color of the ingress Service Frame.

3333

Three Ways to Apply Bandwidth Three Ways to Apply Bandwidth Profile to a Service FrameProfile to a Service Frame

• Per ingress UNIPer ingress UNI• Per EVC at the ingress UNIPer EVC at the ingress UNI• Per CoS instance at the ingress UNI Per CoS instance at the ingress UNI

(see below for CoS identification)(see below for CoS identification)• Multiple methods can apply at a UNI Multiple methods can apply at a UNI

but configuration must be such that but configuration must be such that only one Bandwidth Profile is applied only one Bandwidth Profile is applied to each ingress Service Frameto each ingress Service Frame

3434

Bandwidth Profile PolicingBandwidth Profile Policing

• GreenGreen– Deliver Service Frame with performance Deliver Service Frame with performance

levels as per the Service Level Agreement levels as per the Service Level Agreement for the CoS instancefor the CoS instance

• YellowYellow– Deliver Service Frame but Service Level Deliver Service Frame but Service Level

Agreement for the CoS instance does not Agreement for the CoS instance does not applyapply

• RedRed– DiscardDiscard

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Two Ways to Identify CoS Two Ways to Identify CoS InstanceInstance

• EVCEVC– All Service Frames mapped to the same All Service Frames mapped to the same

EVC receive the same CoSEVC receive the same CoS

• <EVC,set of user_priority values><EVC,set of user_priority values>– All Service Frames mapped to an EVC All Service Frames mapped to an EVC

with one of a set of user_priority values with one of a set of user_priority values receive the same CoS receive the same CoS

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Class of ServiceClass of Service

• A Class of Service is defined by three A Class of Service is defined by three performance objectivesperformance objectives– Frame Delay: P percentile of delay Frame Delay: P percentile of delay ≤ d ≤ d

msecmsec– Frame Jitter: Definition TBDFrame Jitter: Definition TBD– Frame Loss: Percent of frames lost ≤ p%Frame Loss: Percent of frames lost ≤ p%

• Phase 1 will cover only Point-to-Point Phase 1 will cover only Point-to-Point EVCsEVCs

3737

““Ethernet for MAN-kind”Ethernet for MAN-kind”

www.MetroEthernetForum.orgwww.MetroEthernetForum.org

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