Dell Force10 E300, Configuration Manual, Page: 93 / 1262

802.3ah | 93
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802.3ah
802.3ah is available only on platform:
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A metropolitan area network (MAN) is a set of LANs, geographically separated but managed by a single
entity. If the distance is large—across a city, for example—connectivity between LANs is managed by a
service provider. While LANs use Ethernet, service providers networks use an array of protocols (PPP and
ATM), and a variety access technologies. Implementing Ethernet from end to end, across the service
provider network, simplifies design and management, increases scalability and bandwidth, and reduces
costs.
Ethernet in a service provider environment introduces the concept of Carrier-class Ethernet and requires
some basic management and diagnostic tools. Ethernet Operations, Administration, and Maintenance
(OAM) is that toolset, which can be used to install, monitor, troubleshoot, and manage Ethernet
infrastructure deployments. It consists of three main areas:
1. Service Layer OAM: IEEE 802.1ag, Connectivity Fault Management (CFM)
2. Link Layer OAM: IEEE 802.3ah, Ethernet in the First Mile (EFM) OAM
3. Ethernet Local management Interface (MEF-16 E-LMI)
Link Layer OAM Overview
Link Layer OAM introduces the toolset required to effectively monitor the link between the customer and
service provider, which is called
the first mile . Currently, service providers use a variety of access
technologies including ISDN, DSL, and coax cable in the first mile. Implementing Ethernet here reduces
the types of equipment in the subscriber access network, simplifying installation and management, and
increasing bandwidth.
Link Layer OAM performs four primary operations for the purposes of link status, performance
monitoring, and fault detection and isolation for Ethernet in the First Mile:
• OAM Discovery— detects whether the remote system is OAM capable, and negotiates OAM
parameters.
• Link Event Monitoring —defines a set of events that may impact link operation, and monitors the link
for those events.