ATM, however, never made it to the desktop, a necessity for moving from wide-area to local-area networking. As a result, the experts in IP routing developed new concepts for tagging flows of IP information and managing those flows as if they were ATM virtual circuits.
Multiprotocol label switching, or MPLS, became a core standard for all in the public-networking data world and was even extended into optical transport through the generalized-MPLS standard. MPLS became a mature method of controlling IP flows when the Martini and Kompella extensions were added, allowing easy ways of creating virtual private networks and virtual private LAN services, respectively.
The final market force influencing the battle for the edge resulted from the incumbent local-exchange carriers' all-but-total victory over competitive LECs during the recession. The CLECs had built out networks based on IP and Ethernet alone, but the ILECs needed to justify their existing capital equipment based on Sonet rings. The regional Bells were serious about wanting to move to all-IP networks but needed to do so in a way that preserved legacy TDM circuit-switched systems extending to end users, particularly the fiber-based TDM Sonet rings in metropolitan areas.
'God boxes'
While the first generation of edge device OEMs-coming out with products in 2000-2001-looked for clever ways to meld resilient packet rings, Sonet and Ethernet, the next crop must assume a long life for Sonet rings currently in the ground. The newest Sonet add-drop multiplexer (ADM) "God boxes" are cost-effective small systems that can speak Ethernet and MPLS. White Rock Networks Inc. set the standard for low-end Sonet access systems, and now everyone from Fujitsu Network Systems to Turin Networks is looking for a "right-sized" ADM.
What are the common assumptions in this sector? Ethernet at 1 Gbit/second and slower will migrate out from enterprises to subtended ring networks, and 10-Gbit Ethernet may be spoken natively all the way to the MAN/WAN core. MPLS and G-MPLS, initiated in the core, will push out to the edge and may intrude upon multisite enterprise networks as well. All traffic will ride on IP at Layer 3, with only small amounts of circuit-switched voice remaining in any global networks by late in the decade.
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