The company used a line card based on the C-5 network processor of C-Port Corp., a Motorola company, originally designed for packet-over-Sonet applications, and configured a portless version for label switching. The line card will be offered in June for Extreme's Black Diamond switch.

Extreme also added dedicated software to allow the mapping of a variety of flow-based and connection-oriented services to MPLS frames. Those include IEEE 802.1p, the Internet Engineering Task Force's Differentiated Services and a variety of Sonet-mapped services, all linked to specific MPLS label-based flows. Even the virtual-LAN tags defined for 802 local-area networks can be mapped to MPLS, allowing transparent LAN services to be carried within MPLS tunnels.

Sam Halabi, vice president of Internet Protocol carrier marketing and business development at Extreme Networks, said carriers understood the advantages of Ethernet services and needed a way to offer the granularity of time-division multiplexed circuit-switched services within an Ethernet topology. Early dedicated Ethernet carriers using dark fiber represent a customer base for Extreme. For example, Yipes Communications Inc. will implement Extreme's MPLS in its metropolitan Ethernet networks, said Yipes chief technology officer Kamran Sistanizadeh.

Even traditional Sonet-based carriers that wish to offer new types of data services represent a potential customer base for the switches, Halabi said, adding that Extreme does not expect to totally replace Sonet add-drop muxes in existing carrier networks.