Can T-MPLS Finally Unhook SONET/SDH Transport?
By Scott Clavenna
Published January 2007; Posted August 2007



Ethernet hasn’t cracked the transport market yet, but a new version of MPLS is promising to help.

Today there is little disagreement that Ethernet has become the dominant driver of growth in carrier data services, leaving frame relay, ATM, and even TDM private lines in its wake. Enterprises continue adopting Ethernet, and carriers are rolling out a diversity of Ethernet options, from simple point-to-point private lines to more complex multipoint services that leverage MPLS for scale and quality of service (QOS). Ethernet is also moving rapidly into carrier networks as an aggregation and transport infrastructure, supporting lower-cost-per-bit backhaul of consumer broadband services, cellular data services and business data services.

For years, this twofold ascendance of Ethernet has been expected to spell the end of SONET as the nearly ubiquitous transport layer for network operators, but each year SONET hangs on, thanks to its robustness, well-established standards and massive installed base. Recently, however, even SONET’s advocates have begun to describe, and standardize, its departure from the stage. What will stand in its place is not necessarily today’s “Carrier Ethernet,” but what is more generally being called “packet transport.”

For enterprise users, packet transport promises a scalable, resilient network infrastructure that pairs the reliability of SONET with the flexibility of Ethernet and IP networking. For network operators, packet transport means an end to the debate between SONET and Ethernet, and an Ethernet-based technology that is “packet friendly” and cost-effective while preserving the deployment, operations and management techniques of SONET. Not surprisingly, the key ingredient in this vision is Multi-Protocol Label Switching (MPLS).


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About the author:

Scott Clavenna is chief analyst at Heavy Reading, specializing in broadband and optical networks market research.


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