Carrier Ethernet Tech Overview

Carrier Ethernet:: Technology Overview and Testing Solution

Copyright Spirent; portions MEF Page 2

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)

http://www.metroethernetforum.net/


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)


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


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


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


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


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.


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


• 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


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


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


MEF Terminology Diagram


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


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


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


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


UNI: User Network Interface, CE: Customer Equipment

CECE

UNIUNI UNIUNI

CECE

Multipoint-to-Multipoint EVC


CECE

UNIUNI

MEF certified Carrier Ethernet products

CECE

UNIUNI


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


CECE UNIUNI

CECEUNIUNI

CECE

UNIUNI

ISPPOP

UNIUNI

Storage Service Provider

Internet


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


CECEUNIUNI

CECEUNIUNI

Point-to-Point EVC

CECE

ISPPOP

Internet

Service Multiplexed

Ethernet UNI

CECE


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


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


CECEUNIUNI

UNIUNI

UNIUNI

CECE

UNIUNI

CECE

Leaf

Leaf

UNIUNI

CECE

Leaf

* Referenced in MEF 10.1 as Rooted-Multipoint EVC


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)


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


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


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


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



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


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


Algorithm

Frames are marked as Green, Yellow, or Red at the Ingress to the MEN


Color Treatment

Red Discard

Yellow Deliver

But SLS does not apply

Green Deliver

SLS applies


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


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


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


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.


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


MEF Membership Continues to MEF Membership Continues to Increase Increase

MEF Certified Services and Devices MEF Certified Equipment Manufacturers and Service Providers


MEF Certification ProgressMEF Certification Progress


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


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


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


Agenda



Ethernet OAM







Summary


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


Standard Bodies Working on CE


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)


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


MEPs, MIPs and ME Levels

Source: White paper by Fujitsu “Ethernet Service OAM: Overview, Applications, Deployment, and Issues”


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


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


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


Common Ethernet Service OAM Frame Format

Source: White paper by Fujitsu “Ethernet Service OAM: Overview, Applications, Deployment, and Issues”


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


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


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


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


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


802.3ah OAMPDU Format

Destination address: 01-80-C2-00-00-02 Slow protocol address

Ether-Type: 88-09

Subtype: 03


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


Example of OAM Interworking


Agenda



Ethernet OAM







Summary


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


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


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


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


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)


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


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


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


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


Example of PB and PBB Format:: 802.1Q 802.1ad 802.1ah

Source: Ericsson Review No. 3 2007, “Carrier Ethernet: The native approach”


PBBN Defined in 802.1ah:: Provider Backbone Bridged Network

Source: IEEE 802-1ah-D4.0


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


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


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


PBB-TE (PBT) Overview Cont…


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


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


T-MPLS Layers


T-MPLS Standard Roadmap


Agenda



Ethernet OAM







Summary


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


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!


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


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


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


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


…And Growing Complexity!


Summary Cont…


Thank You

Date post:	03-Dec-2014
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Carrier Ethernet Tech Overview

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