SAN JOSE, Calif. A broad group of chip and systems makers is taking a fresh approach to the long-sought goal of creating a single interconnect to link all systems in the data center. Broadcom, IBM, Intel and others are in an early development stage with something tentatively called Convergence Enhanced Ethernet (CEE) that in addition to improved data networking could take on jobs handled by Fibre Channel and Infiniband.
Some engineers have been hammering out the concepts behind CEE for a year, although actual work on a specification is still in an early stage in an IEEE work group that oversees Ethernet. On Wednesday (April 4), proponents will present their ideas for the first time to the T11 committee that defines Fibre Channel.
"CEE is a set of enhancements to Ethernet to allow it to better handle all the different classes of traffic in the data center," said Renato Recio, chief engineer in IBM's eServer networking group, one of the engineers leading the effort.
"There's a strong indication from multiple vendors that there are compelling trade offs to go this way, and I believe this will have significant market presence," said Bob Grow, a principal architect at Intel Corp. and chairman of the overarching 802.3 group that defines Ethernet. "Whether [CEE] replaces all the applications people hope is the big question," he added.
Backers say CEE could be most attractive in large data centers such as those run by Wall Street and big web sites such as Amazon and Google. Today data centers typically use Ethernet for networking, Fibre Channel for storage and Infiniband or a proprietary link for clusters. Supporting three nets adds complexity and cost.
CEE hopes to expand the sophistication of Ethernet to handle complex traffic patterns in the data center more gracefully than it does today. The new additions would help morph Ethernet from a "best efforts" technology that sometimes drops packets to a more sophisticated network that can slow traffic selectively to make sure no data is lost.
CEE aims to accomplish this through three new features.
A congestion management capability for Ethernet is already being debated in the 802.1au group chaired by a senior Broadcom engineer. Once that capability is defined, two other features will build upon it.
Another proposed capability is called per priority pause. When a link becomes congested, this feature lets the system slow down only traffic that subscribes to a certain priority level, rather than slowing all traffic.
"This maps Ethernet better to environments where you have multiple layers of cascading switches," said Grow. "A credit-based system such as the one Infiniband uses is OK if there is only one layer of switches," he added.
In addition, CEE backers aim to build upon the congestion management feature a broad priority processing and packet scheduling capability. Finally, the group aims to develop a protocol to automatically detect when an Ethernet device has the CEE enhancements.
CEE is also expected to incorporate work in the Internet Engineering Task Force on something called the Transparent Interconnection of Lots of Links. TRILL is essentially an Ethernet link-layer routing protocol that provides a shortest-path frame routing in multi-hop networks.
Just when CEE will be complete is an open issue. The 802.1au group working on congestion management in Ethernet has not yet picked one of four approaches it is studying. Once it does the other key features "will fall like dominos," said IBM's Recio.