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Agere taps British Telecom algorithm for network processor

Posted: 16 Aug 2004 ?? ?Print Version ?Bookmark and Share

Keywords:unbreakable? access? algorithm? network? processor?

Agere Systems Inc. will implement the so-called Unbreakable Access algorithm suite, developed at British Telecom, in its Payload-Plus family of network processors. The algorithms set up an alternate path over which Internet Protocol (IP) packets and data services can be delivered when a primary path is unavailable, and do so with the same or faster restoration times as physical-layer protection switching.

Agere said it will be the first company to implement Unbreakable Access.

Fujitsu Telecommunications Europe and Marconi Communications, which will supply multiservice access network (MSAN) systems to British Telecom, said their systems will utilize Payload-Plus chips with Unbreakable Access firmware.

The network is the brainchild of BT's CTO, Matthew Bross, who helped design similar packet networks at Williams Communications.

BT's three goals for the network are to offer bundled services on one L1 or L2 link, often VDSL; to improve capital and operational expenses by collapsing network types.

David Sonnier, chief architect for network processors at Agere, said that BT wanted a traffic-management core in a network processor that could handle fast resiliency at the logic level. Nothing would prevent the scheme from being used in conjunction with SONET physical-layer protection switching and restoration, but the intent is for Unbreakable Access to provide a service-restoration method that is independent of both the physical medium used and of the network layer in which recovery takes place.

In the Unbreakable Access scheme, a single IP flow proceeds from the customer premises to the MSAN device, typically a router or multiservice switch. Within that traffic path, carriers can tag a particular subflow as "protected traffic," either at the level of a multiprotocol label-switched path, a field within an IPv4 or IPv6 header, or a tag within a TCP session manager.

The traffic-management block within the data path processor in the router sets up a redundant path for protected traffic. If the primary path is blocked or brought down, best-effort traffic awaits the normal restoration of the network, but low-latency protected traffic takes the alternate path.

The traffic flows converge again in wide-area network cores. Samir Samhouri, marketing director for network processors at Agere, said tests show Unbreakable Access to be "at least as fast as SONET recovery," mandated at sub-50ms restoration. Protected services typically would be used for time-sensitive isochronous or premium high-bandwidth service.

The BT deal comes two weeks after Agere introduced a SONET mapper/framer with advanced programmable restoration methods at the physical layer.

- Loring Wirbel

EE Times

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