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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.
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