Applications Drive Ethernet Diversity

Applications drive standards development. And as Ethernet has spread beyond data center and enterprise applications, Ethernet standards development has diversified. The “need for speed,” is actually relative to the specific application under consideration, and is no longer the sole driver in Ethernet standards work.

In this blog, I'll discuss market-driven applications and the corresponding Ethernet standards work.

Diverse topologies and configurations

As network computing has matured, for instance, enterprises at various scales have adopted diverse configurations or topologies to accomplish their goals.

Hyper-scale data centers are really pushing the bleeding edge. Servers are shifting to 25 GbE, 50 GbE, and 100 GbE, while networks are moving to 100 GbE, 200 GbE, and 400 GbE deployments. Ethernet switches to servers use myriad configurations: blade servers running across a backplane, top-of-rack arrangements with copper cable and middle-of-row or end-of-row arrangements using multimode fiber. The need for speed and diversification in next-gen server topologies is likely to continue and Ethernet strives to keep pace. Each of these applications requires a different combination of Ethernet specifications that includes data rates, throughput, distance, and physical media.

The installed base of Ethernet users, as a whole, is not homogenous; hyper-scale data centers needing the latest, greatest data rates are only part of the picture. Campuses and enterprises are increasingly extending Ethernet’s use from core to end user, and have an array of different needs and diverse starting points in regards to the data rate and distance scale.

Their existing infrastructure is based primarily on Cat 5e and Cat 6 cabling installed to support gigabit Ethernet, which now has 802.3bz standardizing 2.5GBASE-T and 5GBASE-T operation over this same cabling with end users primarily connecting to the network via wireless protocols. Because speed and distance drive cost where physical media are in use, the market pressure for cost-effective solutions also drives lower-speed, shorter-distance applications over myriad physical media.

Different points of origin

Today's 100 Gbps Ethernet solutions are becoming deployable in the campus/enterprise environment, with servers moving towards that speed as well. And while campus data centers have moved from 10 Gbps to 25 Gbps servers and are planning to move to 50 Gbps servers with their next-generation topologies, enterprises typically are at a lower end of performance, and migrating from 10 Gbps servers to 25 Gbps. The simple fact is, not everybody has moved to 10 Gbps.

Thus a diversity of applications is driving current standards development. The IEEE and the IEEE Standards Association recently announced two new IEEE 802.3 projects, and modification of the existing 400 GbE project. These projects will deliver standards that support a number of various Ethernet data rates, throughput and distance over a range of physical media in a cost-effective manner.

Standards work

Task forces have been established and technical decisions are being made in the following areas:  

Let’s take a brief look at each of these three projects.

The data center market for 25 GbE short reach over copper and multi-mode fiber is robust. The IEEE P802.3cc 25 Gbps effort will complete the 25 GbE family of physical-layer specifications (PHYs), and develop new 10 km and 40 km PHYs over single-mode fiber for 25 GbE, which will meet the needs of campus and metropolitan markets. A standard supporting single-lane signaling at 25 Gbps will help lower costs for this application. Completion of this standard is expected in late 2017.

The IEEE P802.3cd 50 GbE, 100 GbE and 200 GbE Task Force will develop the new 50 Gbps Ethernet rate as well as a set of copper and optical PHYs for 50 GbE, 100 GbE and 200 GbE that will leverage common 50 Gbps optical and electrical signaling technologies. Completion of IEEE P802.3cd Ethernet is due roughly in early 2018.

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The IEEE P802.3bs project utilized 50 Gbps single-lane signaling aggregated across eight lanes to develop a definition for 400GbE. Participants realized that the sharing of common 50 Gbps signaling could be used for 200 GbE SMF PHYs, and agreed that it made sense to include 200 GbE as part of the IEEE P802.3bs 400GbE project. The prior successes of 1x/4x families, which include 10G/40G and 25G/100G, illustrated that the development of 50G signaling would then create the 50G/200G family of solutions – with the 802.3bs project creating the 200G SMF variants that used the 50G optical signaling technology.

Additionally, the task force is developing a 500m solution across four parallel single mode fibers, commonly referred to as PSM4, where each fiber will support a serial 100Gbps optical signal.

John D’Ambrosia is known in the industry for his efforts as Ethernet’s advocate. He is a Senior Principal Engineer at Huawei, participating in industry standards efforts driving Ethernet’s ongoing evolution and its move to higher speeds. He chairs several IEEE 802.3 standards activities, is a member of the IEEE 802 Executive Committee, and is the Chairman of the Ethernet Alliance, an organization dedicated to the promotion of all Ethernet technologies.