© 2005 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION1 1 Carrier Ethernet Technologies and Test Applications Reza Vaez-Ghaemi, Ph.D.

1© 2005 JDSU. All rights reserved. JDSU CONFIDENTIAL & PROPRIETARY INFORMATION1

Carrier Ethernet Technologies and Test Applications

Reza Vaez-Ghaemi, Ph.D.

November 2008

2

© 2008 JDSU. All rights reserved. JDSU CONFIDENTIAL & PROPRIETARY INFORMATION2

Drivers for Transport Network Evolution

• Triple Play services• Business services• Mobile backhauling• Carrier-class performance (SLA

guarantees)• Flexible, cost-effective BB Access,• Ethernet and Photonics technologies

3


Carrier Ethernet Requirements

Carrier Ethernet

TDM Support

QoS Protection

Scalability

OAM

• Native Ethernet lacks key capabilities needed for a robust metro core network technology

• Ethernet is continuously being enhanced with key features for carrier grade performance such as:

•QoS: service differentiation and prioritization•Scalability: granularity and number of services•OAM: Monitoring, loopback•Protection: 50ms path protection•TDM support

4


LAN CE PE PEPB PB LANCE

Basic structure of Ethernet Network

Access Backbone, Core WAN, Metro Network

Access

ProviderEdge

Equipment

Transmissiontechnique

Switchingtechnique

CustomerEdge

Equipment

Customer CustomerProvider

Packet oriented

Ethernet

5


Connect networks– Direct, multiple and virtual

VPN realized with native Ethernet• VLAN (802.1p/q); Q-in-Q (802.1ad); MAC-in-MAC (802.1ah)

– Switching in the BB by Ethernet transparent switching– VLAN tag serves as filter, not as switching information.– VPN separation only in the access switch

VPN realized with an IP Network • VPLS (Virtual Private LAN Service); MPLS (Multiprotocol Label Switching)

– Switching in the BB by MPLS label– VPN separation in the whole BB by LSP (Label Switched Path)

LAN CE PE PE LANCEEth Eth

PE

PE

BackboneVPN

PE

PE

PE

6


VLAN tagging - why

• VLAN is a filter function – logical separation of MAC frames

• MAC frames are only valid for dedicated egresses

• Necessary to block frame distribution to everybody in case of Broadcast function

• Used for layer 2 switch based networks

• Necessary if customer also uses VLAN tags

• Inner tag = Customer tag, Outer tag = Service tag

Q in Q

VLAN

• Reduces the adress table of provider backbone switches

• Only MAC adresses of all provider edge equipment are to be learned

MAC in MACProvider Backbone Bridges

PBB

7


Virtual Local Area Network (VLAN) – idea

The idea of VLAN is to segment networks into logical groups rather than physical conditions.

Physical segmentation

provider device

different offices

management

controlling

developmentLogical segmentation

VLAN #1VLAN #2VLAN #3

8


CustomerC-LAN

CustomerC-LAN

ProviderS-LANCE PE PE CE

Customer: With VLANs

VLAN configuration and operation – Q-in-Q

VID MACIP SVLAN MACCVLANIP VID MACIP

Switching in the provider net: SVLAN tag has no switching function. The SVLAN only hides the CVLAN. The MAC addresses of the customer devices

remains visible and are needed for switching. Still transparent switching and flooding based on the customer Ethernet

addresses.This is a big disadvantage in large networks!

Solution: A totally separate (addressing, switching, management) backbone transport network.

PBBN – Provider Backbone Bridge Network (IEEE 802.1ah)

• 802.1ad: Q-in-Q (VLAN-Stacking):– Is necessary, when also the customer is using VLAN in his network.


MPLS VPLS

T-MPLSMPLS-TP

10


What is MPLS ?

• G.8112/Y.1371: “Interfaces for the Transport MPLS (T-MPLS) hierarchy”

• Conceived to be flexibly client of all the relevant transport technologies:– PDH– SDH (POS)– OTN G.709 (GFP)– Ethernet and RPR

• Provides service to all types of client traffic:– IP– Ethernet– ATM and Frame Relay– PDH and SDH (circuit emulation)

11


MPLS-VPN

C

C

CE PE

P

P

PE CE

C

C

P

PLSR

LSR LSR

LSRLSR

LSR

C - Customer Router CE - Customer Edge Router

PE – Provider Edge Router P - Provider Router

LSR – Label Switch Router

• Equipment and Terminology

12


Architecture: The MPLS label...

TTL

20 3 1 8

32 bits

L3 header L2 headerLabel 1 Label 2 Label 3 Label n

IP L L2 IP

MPLS label

L2 headerL3 header Label

SExpLabel

Label stack

ATM VPI/VCI Frame Relay DLCI to to

IP VPI/VCI DLCI

13


LSR

LSR

LSR

Architecture: Ingress LSR

• Located at the edge of an MPLS domain

LSRLSR

LSR

The domain needs a way in ...

IP

IP

Ingress

EdgeIP

• Represents the ingress to an MPLS domain • Assigns packets to an FEC• Inserts the first label

14


LSR

LSR

LSR

Architecture: Egress LSR

LSRLSR

LSR

… and a way out.

IP

IP

Egress

EdgeIP

Edge

• Located at the edge of an MPLS domain• Represents the egress to an MPLS domain

• Removes the last label and re-creates the original packet

15


The need for VPLS

• Switched Ethernet network architectures have proven to be successful in delivering high-performance, low-cost L2 VPN multipoint services.

• However, as the size of these switched Ethernet networks has continued to grow, the limitations on the scalability of this architecture has become increasingly apparent. These limitations include:– Limited VLAN address space per switched Ethernet domain – Scalability of spanning tree protocols (IEEE 802.1d) for network

redundancy and traffic engineering – Ethernet MAC address learning rate, which is important to minimize

broadcast traffic resulting from unknown MAC addresses.

• To address the limitations of both MPLS L3 VPNs and Ethernet switching, innovations in network technology for delivering multipoint connectivity services have led to the development of a new technology, which is known as Virtual Private LAN Service or VPLS.

16


What is VPLS ?

• Virtual private LAN service (VPLS) is an MPLS application and is used to provide multipoint to multipoint L2 VPN services.

• It allows geographically dispersed sites to share an Ethernet broadcast domain by connecting each site to an MPLS-based network.

• In contrast to Layer-2 MPLS VPNs, which allow only point-to-point layer 2 MPLS tunnels, VPLS allows a full mesh of sites, allowing any-to-any (multipoint) connectivity.

• Assuming our VPLS is MPLS-based, we can use Label distribution protocol (LDP) to create LSPs (mentioned in the previous chapter).

• VPLS can also support VLANs on the customer side of a PE, in that case, we must encapsulate a VLAN ID in each packet that is sent

17


VPLS Reference Model

• The customer sites are connected through a service provider network, which appears as a Layer 2 switch.

• Customer sites are connected to the service provider network at the Provider Edge (PE). All PEs in the network are connected together with each tunnel carrying multiple pseudo-wires. Pseudo-wires are point-to-point connections setup for each offered service between a pair of PEs.

18


MPLS and VPLS – The small difference

VPLS - Virtual Private LAN Service– The customer sees his “own” Layer 2 Ethernet network.– The complete Ethernet packets of the customer are transferred.– PE device emulates to the CE a virtual L2 Ethernet LAN – CE can be a router or an Ethernet switch.

MPLS - Multiprotocol Label Switching– The customer sees his “own” Layer 3 IP network.– Only the IP part of the packet is transmitted. Ethernet is terminated at the PE.– PE device emulates to the CE a virtual router.– CE must be a router.

PECE

CE

L2 Eth L3/IP+MPLSL2 Eth

PECE

CE

L3 IP L3/IP+MPLSL3 IP

19


T-MPLS - why

• Makes MPLS a „Carrier Class Network“:Combines the advantages of a reliable packet-based technology (MPLS) with circuit based transport networking.

• Based on IP/MPLS technologybut simpler implementation:

- removes features not relevant for connection oriented applications

+ addresses critical transport functionality gaps

• Connection oriented only

• Standardized by ITU-T

• Key enhancements: + point-to-point bi-directional LSP

+ end to end LSP protection (50ms) + advanced OAM support (optimal control of network resources) lower OPEX

T-MPLS

20


Differences MPLS and T-MPLS

• MPLS uses uni-directional LSPs T-MPLS uses bi-directional LSPs (it pairs forward and backward LSPs)

• MPLS uses PHP (Penultimate Hop Popping): removes the MPLS label one node before the egress - to minimize router processing)T-MPLS doesn‘t use PHP

• MPLS uses LSP Merge: all traffic forwarded along the same path to same destination may use the same MPLS label – make OAM and perf.monitoring difficult – it‘s not connection orientedT-MPLS doesn‘t use LSP Merge

• MPLS uses ECMP (Equal Cost Multiple Path):it allows traffcic within one LSP to be routed along multiple NW paths – requires additional IP header and MPLS label processing and makes OAM complexT-MPLS doesn‘t use ECMP

21


T-MPLS - Positioning

T-MPLS shifts itself under the packet based networks, in order to organize the “classical” transport networks.

Packet based transport networks: IP Netze

MPLS (= „IP-MPLS“ according IETF)

Data (L2 & L3

VPN)

Voice(VoIP)

Internet (WEB, email)

Video(IPTV, VoD)

Optical transport networks: OTN, WDM, fiber

TDM based transport networks:

(PDH), SDH

Packet based transportnetworks:

Ethernet, RPR

T-MPLS (= GMPLS without MPLS according ITU-T)

22


Gain of T-MPLS?

• Network operator– „Carrier Class“ packet switched system for „Carrier Grade“ MPLS

• Connection oriented• Management, control and quality is based on proven technologies

(e.g. SDH APS)• Convergence of layer 2 (Ethernet) and layer 3 (IP) client signals over one

packet based transport technique• With GMPLS one control plane for all network layers

(packet, TDM, lambda, fiber)• OPEX and CAPEX lower as with IP MPLS

The question remains: OPEX and CAPEX still lower as with PBB-TE?

Possible responds: Depends on which infrastructure (SDH) is already available and how the further network development is planned.

23


Why MPLS-TP?

• Statically configure LSP/PWE via management plane• Deliver OAM for LSP/PWE• Consistent OAM for multi-layer networks which enables

interworking of services such as LSP, PWE, and L2• Offer MPLS LSP and PWE as a transport service• Manage LSP/PWE at nested levels (path, segment)• Additional protection switching• Congruent OAM and Traffic including LAG/ECMP

24


What is MPLS-TP?

• Definition of an MPLS Transport Profile (TP) within IETF MPLS standards– Based on PWE3 and LSP forwarding architecture– IETF MPLS architecture concepts

• Major concept is LSP. • PW is a client.

25


LSP and OAM

• A segment is between MEPs• OAM is end to end or per segment• In SDH/OTN and Ethernet segment

• OAM is implemented using Tandem Connection Monitoring (TCM)• The OAM in each segment is independent of any other segment• Recovery actions (Protection or restoration) are always between MEPs

i.e. per segment or end to end

26


Associated Channel Level (ACH)

• Generalised mechanism for carrying management / OAM information– OAM capabilities : Connectivity Checks (CC) and “Connectivity

Verification” (CV)– Management information: Embedded Control Channel (ECC)– Data Communications Network (DCN) – Signalling Communication Network (SCN)– APS information

27


How does it work?

• Processed by the pseudo-wire function on the end-points• End point or Pseudo-wire stitch point

– Verifies the operational status of the pseudo-wire– Working with the native attachment circuit technology

• An inter-working function with the native attachment circuit OAM.• Transport and act upon native attachment circuit OAM technology


PBB

PBT/PBB-TE

29


Why PBB?

• Eliminates address space scalability issue

• Solves MAC table size issue

• Works in conjunction with 802.1ad (Q in Q)

30


What is PBB?

MAC(A,B,C)

MAC(H,I)

MAC(J,K,L)

– A PBBN is its own virtual bridged local area network, which is completely under the administrative control of the backbone provider.

– Switching: Transparent switching and flooding based on the PE MAC addresses.

MAC(S,T,U)

1

23

Address cachePort 1: WPort 2: XPort 3: Y,Z(W) (Y)

(X) (Z)

PE

PB

BackboneBB-Access Access

B U B UB W YB U I

MAC Addresses of PE switches

– By introduction of a further MAC layer (MiM) a clear separation between customers and provider results to addresses, switching and management.

– For data separation, PBB adds an I-tag and a B-tag. – Customer data (MAC addresses, VLAN tags) are transparently transported. – Multiple spanning tree enables to distribute the backbone load to several even

parallel paths. Normally a MST per VLAN.

31


PBB – 802.1ah detailed frame format

B-DA, B-SA: Backbone Destination und Source AddressTPID: Tag Protocol Identifier (Indication, which TCI follows. C-, S-, B, or I-TCI)

B-PCP: Backbone VLAN Priority Code Point (Shows the CoS for prioritized transport.)

B-DEI: Backbone VLAN Drop Eligible Indicator (Shows whether the frame can be preferred

B-VID: Backbone VLAN ID dropped in overload situations.)

B-TCI: Backbone TAC Control InformationI-PCP: Service Instance Priority Code PointI-DEI: Service Instance Drop Eligible IndicatorI-SID: Service Instance IdentifierRES1/RES2: Reserved for future applications

B-TCI I-TCI

FCSB-SAB-DA

TP

ID

B-V

ID

B-D

EI

B-P

CP

TP

ID

I-SID

I-DE

I

I-PC

P

RE

S1

RE

S2 Payload

48 48 16 3 1 12 16 3 1 2 2 24(120) 3260-1522

B-TAG I-TAG

32


PBB/PBB-TE Test

• Terminating PBB trunks, testers T1 and T2 perform an end-to-end layer 2 test configured with B-Tag fields in Mac in Mac format.

• Testers only filter on B-MAC/B-VID/(I-SID) and handle everything else in the frame as part of the payload.

Customer 1 Site A

Customer 2 Site A

Customer 2 Site B

Customer 1 Site B

SA

Payload

S-Tag

DA

DA

Payload

SA

S-Tag

Payload

C-VID

SA

DA

B-VID

I-SID

B-SA

B-DA

S-Tag

Payload

C-VID

SA

DA

B-VID

I-SID

B-SA

B-DA

CB

CB

CB

CB

PB

PBPB

PBBEB BEB

BCB

BCB BCB

BCB

T2S-Tag

Payload

C-VID

SA

DA

B-VID

I-SID

B-SA

B-DA

S-Tag

Payload

C-VID

SA

DA

B-VID

I-SID

B-SA

B-DA

T1S-Tag

Payload

C-VID

SA

DA

B-VID

I-SID

B-SA

B-DA

S-Tag

Payload

C-VID

SA

DA

B-VID

I-SID

B-SA

B-DA

BCB-BEB Interface

BCB-BEB Interface


Ethernet OAM

34


Ethernet OAM Layers

Services

Connectivity

Transport/Link

IEEE 802.1ag, ITU and MEF

ITU Y.1731 and MEF

EoSDH (ITU)

EFM (IEEE802.3ah)

EoTDM(ITU)

35


Ethernet OAM Standards Activities

UNI UNI

Media Convrtr

Media Convrtr

Carrier Edge

Carrier Edge

Media Convrtr

Media Convrtr

IEEE 802.3ah

MEF & ITU Y.1731

Access Link OAM Access Link OAM

IEEE 802.1ag, MEF & ITU Y.1731

Connectivity Layer OAM

Service Layer OAM (UNI to UNI)

100FX 100FXCarrier NW

802.1aj dem

arcation

device

802.1aj dem

arcation

device

CPECPE

36


Ethernet OAM Standards

Services and Performance

(ITU Y.1731/MEF)Basic Connectivity(IEEE 802.1ag,ITU)

Transport/Link(802.3ah EFM)

Discovery Discovery Discovery

Continuity check (keep alive)

Continuity check Remote failure indication: Dying gasp, link fault & critical event

Loopback (non-intrusive and intrusive)

Loopback Remote, local loopback

AIS/RDI/Test AIS Fault isolation

Link Trace Link Trace Performance monitoring with threshold alarms

Performance management Status monitoring

37


Management Layer Comparison

SONET– Line/Section/Path

• Line– Loopback– RDI– Signal/line quality (BER)

• Section– Loopback– RDI

• Path– Loopback– RDI

Ethernet– Link/Domains

• Link– Loopback– RDI– Event Monitoring– Signal/line quality

(frames/symbols)• Domains

– CFM Loopback (“ping”)– CFM Linktrace (“traceroute”)– CFM Connectivity Check

38


Ethernet First Mile OAM

• Why not just use IP-based management (SNMP, Telnet, etc.)?• IP infrastructure must be operational and properly configured• Some networks don’t use IP• Security vulnerability

• IEEE 802.3ah OAM• Provides low level Ethernet OAM functionality at FM• Isolated to First Mile segment• Complements SNMP and other IP-based NMS• NMS can be secure and away from the user• Media independent: Fiber (Active P2P or PON), Copper• Uses standard Ethernet frames – slow – 10 frames/sec• Backward compatible with non-802.3ah Ethernet• Requires minimal configuration (almost “plug and play”)

39


Ethernet First Mile OAM

• Defines:• EDD – Ethernet Demarcation Device (NID)

• Functions:• Monitor Link performance• Fault detection and notification (signaling)• Loopback testing

NMS

CarrierNetwork

802.3ah802.3ah

First Mile(Access Link)


EDDEDD CPECPE

40


Ethernet 802.3ah Protocol

•Discovery – Exchange of capabilities and i.d. info•Periodic state update / monitoring•Link event notifications (performance threshold alarms)•Remote failure notification –

•Link faults (Network side port) including Unidirectional•Dying Gasp – catastrophic / non-recoverable failures•Critical events – vendor specified events

•Remote Loopback•Read MIB info / stats•Vendor extensions

NMS

CarrierNetwork

802.3ah802.3ah



EDDCPE EDD CPE

41


Management of Network Edge

Multiple standards provide building blocks for managing the access

• 802.3ah OAM addresses how to manage physical from the PE to the MAC layer of the remote device

• MEF ELMI addresses how to manage the UNI of the remote device

• 802.1aj Two-Port MAC Relay addresses how to manage a potential customer demarcation device

Each protocol adds some unique functionality, and (unfortunately) adds some overlap functionality with the other standards

UNI

PE

Service Provider 802.3ah OAM

MEF ELMI802.1aj TPMR

MAC Device

CPE

42


IEEE 802.1aj TPMR

• IEEE 802.1aj Two-Port MAC Relay– Defines protocols for interactions carrier bridge and remote 2-port

relay device that might be used for demarcation– Uses SNMP natively over Ethernet (no IP!)***

• Configuration of remote parameters***– VLAN behavior– CoS and QoS characteristics of interfaces– Forwarding behavior (data and L2 protocols)

• Status information between carrier and customer***– Utilizing IEEE 802.1ag

• Covers configuration and status of all aspects of remote device IF the device is a simple two-port relay forwarder– Does not apply to bridges, routers, etc. which may also implement

UNI or forwarding functionality– Mostly intended for CARRIER owned demarcation device

***Tentatively

43


Ethernet Service OAM

• Being standardized by Metro Ethernet Forum and ITU (Y.1731)

• Builds upon IEEE 802.1ag functions by utilizing timestamps and other fields to monitor SLA metrics for Ethernet services

• Measures latency, jitter, loss, etc. end-to-end across any domain

• Used to validate SLA performance of Ethernet service across any kind of underlying network

44


Ethernet OAM Implementation

• Focus on end-to-end OAM (IEEE802.1ag, ITU Y.1731)– incorporating last segment OAM (IEEE802.3 ah)

• End-to-end service OAM:– Continuity Check

– Loopback

– Performance Monitoring

• Frame Delay, Frame Delay Variation, Frame Loss, Availability

Operator BOperator A

802.1ag/ Y.1731 (UNI-N to UNI-N ME)

802.3ah(Access Link)

EDDEDD CPECPE

45


IEEE 802.1ag CFM

• CFM = Connectivity Fault Management (in progress)• Partitions network into hierarchical administrative domains• Basic connectivity checking and troubleshooting across any

domain, and across multiple domains at the same time• Partitions big problem into pieces & controls visibility

Service Provider

Operator Operator

Customer End-to-End Metrics

Provider End-to-End Metrics

Operator Metrics Operator Metrics

46


IEEE 802.1ag CFM

• Providing “ping” and “traceroute” equivalents for bridged (rather than routed) networks

– Loopback (= Ping): Given MAC address and VLAN tag, verify connectivity

– LinkTrace (= Traceroute): Given MAC address and VLAN tag, find the path between the local source and that destination

• Also provides continual connectivity checking (a.k.a. heartbeat) to proactively monitor end-to-end availability and packet loss

47


Continuity Check (CC) OAM

• CC OAM Defined per EVC, one-way connectivity monitoring• Loss of Continuity (LOC) is declared (only at the sink side) upon

3.5 seconds without receiving CC OAM frame • Loss of Continuity (LOC) is cleared upon sink receiving 2 CC

OAM frames within a window of several seconds• Upon CC failure

– Send trap– Update active alarm log– Update statistics– Optional uplink switch-over


CC Sink

CC SourceCC OAM Frames

EDDEDD CPECPE

48


Loopback (LB) OAM

• Per Link/Port: Remote loopback minimizes a false repair calls • Non-intrusive loopback: Defined per EVC/service monitoring

– one VLAN is looped back while others continue to provide their services

• LB Failure is declared upon 2 sec without receiving OAM frame • Upon LB failure

– Send trap; Update active alarm log; Update statistics

– Optional uplink switch-over


MEPLB OAM Request

LB OAM Reply

MEP

EDDEDD CPECPE

49


Performance Monitoring (PM) OAM

• Defined per service (EVC+CoS), allows for in-service,

end-to-end SLA monitoring

• Measured parameters

– Frame Delay, Frame Delay Variation, Frame Loss, Availability

• Performance Measurements traps– Traps sent upon: {# Frames} crossing {Objective} within {Sampling Time}

– The above applies for both ‘Rising’ and ‘Falling’ thresholds definition

• Statistics are collected per 15 minutes intervals; Cyclic 96

intervals kept (24 hours)

50


Test Application Field

• Analyze/Generate OAM errors/alarms

• Performance Measurements

• Loopback tests

UNI UNI

Media Convrtr

Media Convrtr

Carrier Edge

Carrier Edge

Media Convrtr

Media Convrtr

IEEE 802.3ah

MEF & ITU Y.1731

Access Link OAM Access Link OAM

IEEE 802.1ag, MEF & ITU Y.1731

Connectivity Layer OAM

Service Layer OAM (UNI to UNI)

100FX 100FX

..

.

Carrier NW

802.1a

j dem

arcation

de

vice

802.1a

j dem

arcation

de

vice

CPECPE

© 2005 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION1 1 Carrier Ethernet Technologies and Test Applications Reza Vaez-Ghaemi, Ph.D.

Documents

label slide

native ethernet vlan

customer tag

customer ethernet addresses

mpls label vpn separation

mpls vpls tmpls mplstp

mpls domain lsr

idea of vlan