Offering Ethernet services at Layer 2, therefore, enables a
service provider to sell to new groups of customers.
Reduction in Operational Expense Opponents of MPLS often portray it as a complex
technology to operate. In fact, MPLS has a range of advanced troubleshooting tools??”
some inherited from IP (such as ping and tracereoute), some enhanced from their IP
equivalents (such as LSP ping/traceroute), and some new (for example VCCV). The
control plane, which again is often seen as complex, is the most effective way to ensure
that all nodes in the network have the same view of network status. EoMPLS is also
a good mechanism for separating customer and provider domains because separate
service instances are configured per customer and knowledge of a service instance is
constrained to the PE nodes that have local ports that are members of that instance.
Ethernet-based approaches to providing Carrier Ethernet have, in fact, copied many
of their ideas from EoMPLS (for example, 802.1ah Provider Backbone Bridging uses
???MAC in MAC??? to separate the customer and provider MAC address spaces??”resulting
in an encapsulation rather similar to that of Ethernet over MPLS over Ethernet).
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