Metropolitan Ethernet Networks

Estella Kang

Matt Powers

SC441 Computer Networks – Independent Study

Boston University

Typically covers several hundred miles of concentrated metropolitan areas

Explosion of Internet traffic and IP services demand for rapid scalability and dynamic functionality

Service and operational cost reduced Scalable – up to 100Gbps Simple – fewer protocol conversion

Full suite of carrier-class Ethernet services

Ethernet switchingStatistical multiplexing functionalityBandwidth-on-demand service

Service and managementScalabilityNetwork ReliabilityCo-existence with existing

infrastructureTopological flexibilityReduction in operational and

network costs

A Metro Ethernet is a computer network based on the Ethernet standard and which covers a metropolitan area. It is commonly used as a metropolitan access network to connect subscribers and businesses to a Wide Area Network, such as the Internet. Large businesses can also use Metro Ethernet to connect branch offices to their Intranet.

A typical service provider Metro Ethernet network is a collection of Layer 2 or 3 switches or routers connected through optical fiber. The topology could be a ring, hub-and-spoke (star), or full or partial mesh. The network will also have a hierarchy: core, distribution and access. The core in most cases is an existing IP/MPLS backbone, but may migrate to newer forms of Ethernet Transport in the form of 10G or 100G speeds.

Ethernet on the MAN can be used as pure Ethernet, Ethernet over SDH, Ethernet over MPLS or Ethernet over DWDMSM341073

Pengenalan Teknologi dan Jasa Telekomunikasi Semester Ganjil Tahun Ajaran 2009 - 2010 6

The main advantages of an MPLS-based Metro Ethernet against a pure Ethernet are: Scalability: pure Ethernet MAN are limited to a maximum of 4,096

VLANs for the whole network, when using MPLS, Ethernet VLANs have local meaning only (like Frame Relay PVC).

Resiliency: pure Ethernet network resiliency relies on STP or RSTP (30 to 1 sec convergence) while MPLS-based MANs use MPLS-based mechanism

Multiprotocol convergence: with the maturity on pseudowires standards (ATM VLL, FR VLL, etc.) an MPLS-based Metro Ethernet can backhaul not only IP/Ethernet traffic but virtually any type of traffic coming from customer networks or other access networks (i.e. ATM aggregation for UMTS).

End to End OAM: MPLS-based MAN offers a wider set of troubleshooting

The Metro Ethernet Forum (MEF) has defined two types of services that can be delivered through Metro Ethernet: E-Line also known as Virtual Leased Line and Point-to-Point. E-LAN also known as Virtual Private LAN Services, Transparent LAN

Services and MultiPoint-to-MultiPoint. SM341073 Pengenalan Teknologi dan Jasa Telekomunikasi Semester Ganjil Tahun Ajaran 2009 - 2010 7

Ethernet Private Line Dedicated UNIs for Point-to-Point connections

MEN

Ethernet UNI

Ethernet UNI

Ethernet UNI

Point-to-Point EVCs (dedicated BW)

CE

Ethernet Private Line using E-Line Service type

Private Line Analogy to E-Line Service

Internet

ISPPOP

Storage SP

Ethernet UNI

MEN

OC-3

OC-3

DS1

Dedicated TDM circuits

CE

Internet

ISPPOP

Storage SP

DS3CE

CE

CE

CE

Ethernet Virtual Private Line Supports Service Multiplexed UNI Point-to-Point VPN for site interconnectivity

CECE

MEN

Ethernet UNI

Ethernet UNIService

Multiplexed Ethernet UNI

Point-to-Point EVCs

CE FR CPE

FR CPE

MEN

FR UNI

FR UNI

FR UNI

Point-to-Point FR PVCs

Ethernet Virtual Private Line using E-Line Service type

Frame Relay Analogy to E-Line Service

FR CPE

Metro core and metro access ring topology

ADM

DACS

TDM

Complex, multi-tiered, hierarchical network

Limited Scalability

Expensive

Label switching to forward data by mapping VLAN tags to label switched paths (LSPs)

Load sharing by switching path around bottlenecks to less congested links

Dedicated backup LSP and fast reroute when a connection failure occurs

Pada kecepatan tinggi IP terlalu komplek.

Pada kecepatan tinggi IP terlalu memakan resource CPU.

Operator perlu teknologi yang effisien.

Tujuan direct hanya terbatas. Misalnya Lampung --> Jakarta, Medan,

Surabata dan Internet. Sangat terbatas, tidak banyak tujuan

kecuali Internet.Aplikasi pelanggan juga terbatas.

E-mail, web, sekali-sekali video conference.

Perlu customisasi per pelanggan yang mudah.

Label Switch – jauh lebih sederhana & effisien.

TCP/IP – kompleks & tidak effisien.

Label Switch – jauh lebih baik untuk backbone daripada IP.

LIB= Label Information BaseLSR = Label Switched Router

LSR, Label Switched Router – router yang mampu melakukan switching dengan label.

LIB, Label Information Base – kira-kira tabel routing label tempat melihat outbound Interface & label yang digunakan utk mengirim paket.