Metropolitan Area Network Evolution

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 frame without VLAN Tag FCS Data Type/ Length Source address Destination address • Ethernet VLAN (802.1 Q) • 32 bit VLAN tags which contain 12 bit VLAN ID Ethernet frame with 32 bit VLAN Tag (802.1Q) FCS Data Type/ Length Tag Source address Destination address 32 bit TCI- Tag Control Identifier TPID- Tag Protocol Identifier 16 bit 16 bit VLAN ID CFI 802.1p TPID- Tag Protocol Identifier 12 bit 1 bit 3 bit 16 bit

Evolution of Ethernet to Carrier Grade Ethernet(3) Ethernet frame without VLAN Tag FCS Data Type/ Length Source address Destination address • Provider Bridge (IEEE 802.1ad) • Two VLAN tags and hence called Q-in-Q Ethernet frame with 32 bit VLAN Tag (802.1Q) FCS Data Type/ Length Tag Source address Destination address Ethernet frame with 32 bit VLAN Tag (802.1ad) FCS Data Type/ Length C-Tag S-Tag Source address Destination address

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 Backbone Ethernet Frame B-FCS Customer Ethernet Frame I-Tag Type/ Length B-Tag B-Source address B-Destination address 32 bit 32 bit 16 bit 32 bit 48 bit 48 bit 64-1492 Bytes Customer Ethernet Frame FCS Data Type/ Length VLANTag Source address Destination address 32 bit 16 bit 32 bit 48 bit 48 bit 64-1492 Bytes

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

Primary active path Customer A site 1 Customer A site 2 Provider edge bridge Service provider network Provider backbone bridge Protection path Example of Provider Bridge Backbone with Traffic Engineering (PBB-TE) IEEE 802.1ag

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 UNI UNI 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

Metro Ethernet deployment models(5) SDH based

Metro Ethernet deployment models(6) 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

Analysis of Packet carrier transport technologies (1) • Four metrics to compare PBB-TE and MPLS-TP • Performance • MPLS-TP for voluminous traffic • PBB-TE for medium and low traffic • Scalability • MPLS-TP is more scalable for voluminous traffic • PBB-TE for low and medium loads

Analysis of Packet carrier transport technologies(2) • 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) • 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 scenario • Subscribers or customers of various operators • Access network operators (Fixed and mobile) • Transport network service providers • 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 evolution • Will carrier packet transport networks based on PBB-TE and MPLS-TP standards be soon adopted for transport in MAN? • Will there be lower power consumption for PBB-TE and MPLS-TP products? • Is there a need for heavier cooling arrangements for the products based on PBB-TE and MPLS-TP products? • Will the chip design technology reach the level to process data at 10Gigabit and 100 Gigabit speeds sooner? • Will the regulations for using packet based transport becomes more flexible in the near future, especially in America? • Is it easy to develop or find laborers with the skill set needed to run these technologies? • What is the significance of economies of scale in packet transport technologies? 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 • 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 • 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 • 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 Timing over packet

Reference models proposed by MEF for Ethernet based mobile backhaul Single Domain Reference Model Multi Domain Reference Model

Use case models for single and dual Iub proposed by MEF (1) Legacy Split access Legacy Backhaul

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