metropolitan area network evolution author:jipson paul kolenchery supervisor:prof.raimo kantola...

Metropolitan Area Network Evolution

Author:Jipson Paul Kolenchery

Supervisor:Prof.Raimo Kantola

Instructor:Timo-Pekka Heikkinen

Outline

• Introduction• Drive for Ethernet in metro networks• MAN evolution• Evolution of Ethernet to Carrier Grade Ethernet• Metro Ethernet Forum• Metro Ethernet Deployment models• Analysis of Packet carrier transport technologies• Scenario analysis• Conclusion

Introduction

• MAN-Metropolitan Area Network• MAN implementation options• Traffic pattern in MAN• Packet carrier transport in MAN

– Ethernet in MAN

• Options for Ethernet transport– Native Ethernet based PBB-TE– MPLS-TP– SDH based Metro Ethernet

Drive for Ethernet in metro networks• Traditional MAN deployments

– TDM based – Best suited for voice

• TDM interfaces– Bandwidth grows in step function– BW scaling requires provisioning at CPE and Central

office which increases OPEX

• Ethernet interfaces– Fine grained granularity in bandwidth scaling– Bandwidth scaling requires less OPEX

MAN evolution

• MAN evolution– From TDM based implementation to carrier

grade packet transport

• Evolution depends on– Type of service provider– Geographical area– Regulations

Evolution of Ethernet to Carrier Grade Ethernet (1)• Ethernet

– Medium Access Control standard – Invented by Robert M. Metcalfe– IEEE 802.3

• Evolution to carrier grade Ethernet– Ethernet VLAN (IEEE 802.1Q)– Provider Bridge (IEEE 802.1ad)– Provider Backbone Bridge (IEEE 802.1ah-2008)– Provider Back Bone Bridge with Traffic Engineering

(IEEE 802.1Qay)

Evolution of Ethernet to Carrier Grade Ethernet(2)• Ethernet VLAN (802.1 Q)

– 32 bit VLAN tags which contain 12 bit VLAN ID

FCS DataType/ Length

Source addressDestination address

TagFCS DataType/ Length


TCI- Tag Control Identifier

TPID- Tag Protocol Identifier

VLAN ID 802.1p TPID- Tag Protocol IdentifierCFI

32 bit

16 bit 16 bit

12 bit 1 bit 3 bit 16 bit

Ethernet frame without VLAN Tag

Ethernet frame with 32 bit VLAN Tag (802.1Q)

Evolution of Ethernet to Carrier Grade Ethernet(3)• Provider Bridge (IEEE 802.1ad)

– Two VLAN tags and hence called Q-in-Q



TagFCS DataType/ Length


Ethernet frame without VLAN Tag

Ethernet frame with 32 bit VLAN Tag (802.1Q)

Ethernet frame with 32 bit VLAN Tag (802.1ad)

C-TagFCS DataType/ Length


S-Tag

Evolution of Ethernet to Carrier Grade Ethernet(4)• Provider Bridge back bone(IEEE 802.1ah-2008)

– A new header for service provider network– True traffic separation

VLANTag



32 bit

Backbone Ethernet Frame

B-TagB-FCSCustomer Ethernet Frame

Type/ Length

B-Source address

B-Destination address

I-Tag

48 bit48 bit32 bit32 bit32 bit 64-1492 Bytes 16 bit

Customer Ethernet Frame

32 bit 64-1492 Bytes 16 bit 48 bit 48 bit

Evolution of Ethernet to Carrier Grade Ethernet(5)• Provider Bridge Backbone with Traffic Engineering (PBB-

TE) IEEE 802.1ag• PBB + TE• Uses pre-established connection oriented path• Uses faster protection switching

– Two redundant paths per every virtual connection– 802.1ag Connectivity Fault Management messages for

performing OAM• Features

– No loops in the path– No Spanning Tree Protocol (STP)– No dynamic forwarding tables– No flooding

Example of Provider Bridge Backbone with Traffic Engineering (PBB-TE) IEEE 802.1ag

Provider edge bridge

Provider backbone bridge

Customer Asite 1 Customer A

site 2

Service provider network

Primary active path

Protection path

Metro Ethernet Forum

• Formed in 2001• A global consortium of industries

– Promote interoperability and world wide deployment of Carrier Ethernet networks and services

• Defined 5 attributes for Carrier Ethernet– Standardised Services– Scalability– Reliability– QoS– Service Management

Metro Ethernet deployment models(1)• Virtual connections

– Point-to-point EVC – Multipoint-to-multipoint EVC

• Deployment models– Native Ethernet based (PBB-TE)– SDH based– MPLS based (MPLS-TP)

Metro Ethernet deployment models(2)• Point-to-point EVC

Metro Ethernet Network

UNIUNI

Point-to-Point EVC

UNI

Metro Ethernet deployment models(3)• Multipoint-to-multipoint EVC

Metro Ethernet Network

UNI

UNI

UNI

UNI

Multipoint-to-multipoint EVC

Metro Ethernet deployment models(4)

Native Ethernet based-PBB-TE

Customer LAN site 1

Customer LAN site 3

Customer LAN site 2

Customer LAN site 4

Service provider PBB-TE network

Client Ethernet frame

PBB Ethernet frame


Customer LAN site 1

Customer LAN site 3

Customer LAN site 2

Customer LAN site 4



PBB Ethernet frame



SDH based

ADM

ADM

ADM ADMSDH Core MAN Network

Carrier Class Ethernet Switch

ADM

ADM

ADM ADMSDH Core MAN Network

Carrier Class Ethernet Switch


MPLS based

• IP/MPLS is not carrier grade

• Layer-2 MPLS to provide VPN and VPLS service

• MPLS-TP – A carrier grade layer-2 MPLS standard– Jointly developed by ITU-T and IETF – Separate OAM and MPLS forwarding

VPLS using layer-2 MPLS

VPN1

VPN2

VPN3

Customer A,

Site 1

Customer A,

Site 2

Customer B,

Site 3

Customer B,

Site 1

Customer B,

Site 2

Customer A,

Site3

Customer A,

Site 4

VFI for VPN1 VFI for VPN3

Layer-2 Virtual Circuits

Layer-2 LSP

PE1

PE2 PE3

PE4

MPLS backbone

Analysis of Packet carrier transport technologies (1)• Four metrics to compare PBB-TE and

MPLS-TP1. Performance

– MPLS-TP for voluminous traffic – PBB-TE for medium and low traffic

2. Scalability– MPLS-TP is more scalable for voluminous

traffic – PBB-TE for low and medium loads

Analysis of Packet carrier transport technologies(2)3. Reliability

– MPLS-TP • Offers linear protection mechanism• Unidirectional and bidirectional switching• Non revertive operation and revertive operation

– PBB-TE• TE capability of protocol• Protection switching triggered using CFM• Non revertive operation and revertive operation• Load sharing possible

• Both PBB-TE and MPLS-TP offer carrier grade transport with less than 50 ms protection switching interval

Analysis of Packet carrier transport technologies(3)4. Complexity and manageability

– PBB-TE interoperable with installed Ethernet bridges; provisioning needed only at PE

– MPLS-TP is compatible with IP/MPLS; provisioning needed only at PE

– Both PBB-TE and MPLS TP offer strict operator control and efficient OAM

– Low CAPEX for PBB-TE as it is based on native Ethernet standard

– Less skilled labour needed for PBB-TE– Network peering possible in PBB-TE using NNI

while peering is rarely seen in MPLS-TP

Scenario Analysis

Choice of transport network technology

Scenario Analysis

• To propose an appropriate transport technology for meeting the present and future needs of a service provider

• Based on Paul J.H Schoemaker’s method• Three scenarios

– Incumbent MAN service provider– A green field MAN service provider– A MAN service provider selling transport

service to a mobile network

Procedure for Scenario Analysis

• Scenario Planning• Identify scope and time frame of the

scenario• Identify major stakeholders • Identify basic trends• Identify uncertainties• Develop scenario themes• Propose implementation scenarios

Scenario Planning

• Helps to imagine how future would unfold minimising under prediction and over prediction

• Divide our knowledge into two areas: things we know something about (trends ) and elements we are not certain about (uncertainties)

• Simplify the possible outcomes of uncertainties• Identify themes from outcomes of uncertainties

and trends– Literature, survey, simulation results, brainstorming,

and interviews of major stakeholders to propose decision scenarios

Scope and time frame of the scenario• Time frame of this scenario planning is 5 years• Change of traffic pattern

– more voice – less data to more data and less voice• Internet users increasing by 16%• The power consumption of the network elements

worldwide increasing by 12%• Arrival of mobile broadband, increase in data

traffic and QoS requirements• Service providers are searching for a better

technology to meet the needs with less Capex and Opex

The major stakeholders of this scenario1. Subscribers or customers of various

operators

2. Access network operators (Fixed and mobile)

3. Transport network service providers

4. Vendors

Basic trends that effect MAN evolution

• Customer traffic is increasing• The global mobile traffic is expected to increase 26-fold between

2010 and 2015• Most voice services will be replaced by VOIP• VOIP applications needs greater QoS• Fine grained and more dynamic BW scaling needed• Delay in backhaul is a serious concern• Improved OAM mechanism in their network that can isolate and

rectify faults quickly• Electric power and cooling needed for capacity expansion• Service providers are looking for a packet based transport• PBB-TE and MPLS-TP standards are available• 40 Gigabit Ethernet (40GbE) and 100 Gigabit Ethernet(100GbE) are

coming to market soon• Energy Efficient Ethernet (EEE)

Uncertainties in MAN evolution1. Will carrier packet transport networks

based on PBB-TE and MPLS-TP standards be soon adopted for transport in MAN?

2. Will there be lower power consumption for PBB-TE and MPLS-TP products?

3. Is there a need for heavier cooling arrangements for the products based on PBB-TE and MPLS-TP products?

4. Will the chip design technology reach the level to process data at 10Gigabit and 100 Gigabit speeds sooner?

5. Will the regulations for using packet based transport becomes more flexible in the near future, especially in America?

6. Is it easy to develop or find laborers with the skill set needed to run these technologies?

7. What is the significance of economies of scale in packet transport technologies?

1 2 3 4 5 6 7

1 X + - + + + +

2 X X - ? ? ? ?

3 X X X ? ? ? ?

4 X X X X ? ? ?

5 X X X X X ? +

6 X X X X X X ?

7 X X X X X X X

Correlation matrix of uncertainties in MAN

Scenario Themes

• Packet carrier transport is the ultimate solution• Two competing technologies are PBB-TE and

MPLS-TP and both of them have its significance• Choice depends on type of service provider and

type of operators supported by service providers• Three main themes are

– Incumbent service provider– Green field service provider– Service provider providing mobile backhaul

Scenario analysis and decision scenario for an incumbent MAN service provider

OAM network

Edge network

Metro network

Core network

Corporate network

Corporate network

DSL

2G/3G/BTS Network

Controller IP/MPLS network

IP/MPLS network

MPLS-TP PE

MPLS-TP PE

MPLS-TP PE

MPLS-TP PE LSR

LSR

LSR

LSR

IP MPLS-TP IP/MPLS

• Incumbent service provider uses IP/MPLS in its network

• MPLS-TP is compatible IP/MPLS

• Less CAPEX as provisioning is needs only at PE

• Easy to train existing IP/MPLS work force to MPLS-TP

• Choice is MPLS-TP

Scenario analysis and decision scenario for a green field MAN service provider

Customer LAN site 1

Customer LAN site 3

Customer LAN site 2

Customer LAN site 4

PBB edge bridges

PBB core bridges


Client Ethernet PBB Ethernet MPLS

2G/3G/BTS Network

Controller

Metro networkEdge network

MPLS network

MPLS network

Core network

OAM network

Customer LAN site 1Customer LAN site 1




PBB edge bridges

PBB core bridges


Client Ethernet PBB Ethernet MPLS

2G/3G/BTS Network

Controller

Metro networkEdge network

MPLS network

MPLS network

Core network

OAM network • Green field service provider prefers a revolutionary technology at low cost

• PBB-TE needs less CAPEX as it is native Ethernet based

• Less OPEX as provisioning is needed only at PE

• Less skilled work force needed

• E-LAN and E-Line offers fine grained granularity

• Choice is PBB-TE

Scenario analysis and decision scenario for a service provider providing mobile backhaul

RNC

RNC

UNI

UNI

UNI

UNI

BS

E-NNI

PBB-TE CEN-A

PBB-TE CEN-B

MSS MGW SGSN MME/S-GW

PBB-TE CEN-C

E-NNI

VLAN-Trunk

VLAN-Trunk

VLAN-Trunk

VLAN-Trunk

eNB

GGSN

P-GW LTE CN

PS-CNCS-CN

RAN

RNC

RNC

UNI

UNI

UNI

UNI

BS

E-NNI

PBB-TE CEN-A

PBB-TE CEN-B

MSS MGW SGSN MME/S-GW

PBB-TE CEN-C

E-NNI

VLAN-Trunk

VLAN-Trunk

VLAN-Trunk

VLAN-Trunk

eNB

GGSN

P-GW LTE CN

PS-CNCS-CN

RAN

• Large amount of data with HSPA and LTE

• Dynamic nature of traffic in mobile network

• Dynamic and fine grained BW allocation needed

• PBB-TE is the best solution due to fast scaling EVCs, network peering capability of NNI,dynamic provisioning etc

Timing solution in packet carrier transport• Timing-over-packet

– Implemented with Precision Timing Protocol (PTP) IEEE 1588v2 protocol

– Independent of layer-2 and layer-3 networks

• Synchronous Ethernet– Operates in the physical

layer– Defined in ITU G.8261– needs to be supported in

all nodes along the chain between the switching office and the cell site

– link frequency is synchronised to a traceable primary reference clock and physical layer of Ethernet is used to synchronise all participating nodes to the same reference clock

BTS

BTS

RNC

PTP master

Packet network

Unicast timing packets

Network reference

External reference

Timing over packet

Reference models proposed by MEF for Ethernet based mobile backhaul

BTS

BTS RNC

Carrier Ethernet backhaul network RNC

UNI

UNI

UNI

UNI

BTS

BTS

RNC

RNC

UNI

UNI

UNI

UNI

GIWF

GIWF

GIWF

GIWF

CEN-A

CEN-A

CEN-A

CEN-A

E-NNI

E-NNI

E-NNI

Single Domain Reference Model

Multi Domain Reference Model

Use case models for single and dual Iub proposed by MEF (1)

BS

RNC

UNIUNI

GIWF

GIWF

Legacy Network

CEN

BS

RNC

UNIUNI

GIWF

GIWF

Legacy Network

CEN

BS

RNCUNIUNIGIWF GIWF

CENBS

RNCUNIUNIGIWF GIWF

CENCEN

Legacy Split access

Legacy Backhaul

Use case models for single and dual Iub proposed by MEF (2)

BS

RNC

UNIUNI

Legacy Network

CEN

BS

RNC

UNIUNI

Legacy Network

CEN

BS

RNCUNIUNI

CENBS

RNCUNIUNI

CENCEN

Split access

Full Ethernet

Conclusion

• PBB-TE and MPLS-TP give carrier grade features to Ethernet in MAN

• Usability depends on scenarios– Greenfield service provider>PBB-TE– Incumbent service provider>MPLS-TP– For mobile backhauling>PBB-TE

• PBB-TE is suitable for highly varying low and dynamic loads– Suitable for MAN

• MPLS-TP is suited for very high and less dynamic traffic– Suitable for core

Thank You

metropolitan area network evolution author:jipson paul kolenchery supervisor:prof.raimo kantola...

Documents

man ethernet

vlan tag ethernet frame

metro ethernet slide

q ethernet frame

opex ethernet interfaces

backbone ethernet frame

q slide

vlan tags