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The Next Generation BASE-T

The timing of a new initiative is right and it coincides with the market need for higher speed switch-to-server connections.

September 1, 2012  

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t the July 19 plenary meeting in San Diego, Calif. IEEE 802.3 approved the formation of a Next Generation BASE-T Study group. This group is directed to develop a Project Authorization Request (PAR) for the next generation of the IEEE 802.3 BASE-T family of technologies for Ethernet transmission over twisted-pair cabling.

For this month’s column, I wanted to present the rationale for the Next Generation BASE-T development as presented in the Call for Interest (CFI) at the IEEE 802.3 plenary meeting in July. At the same time, I wanted to present the status of the work that is already underway in TIA TR 42.7 subcommittee to develop specifications for next generation cabling.

The purpose of the CFI was to present the market opportunity, to address the technical viability and to answer any questions related to the planned undertaking.

The main presenters included representatives from Broadcom and Intel as well as representatives from APM, Dell and HP who were on hand to answer questions. After the presentation a straw poll was taken to determine how much support there was to pursue this development.

The straw poll indicated an overwhelming support with over 95% of the individuals present voting in favour of this effort.

What applications will benefit from next generation (higher speed) BASE-T? The primary driver for these higher speeds is server LAN ports. Because this application is primarily for data centres and equipment rooms, the needed reach is much less than 100 metres. One of the objectives of the study group will be to determine the reach based upon the application need while balancing power, cost and complexity.

The needs of other applications may also be considered.

New LAN technology starts as add-in card and moves to the motherboard. Today, 10/100/1000BASE-T on motherboard (LOM) is the incumbent. 10GbE is used mostly as add-in and is just ramping up as LOM now.

Support for both 1000BASE-T and 10GBASE-T on same port is a key enabler for LOM and a key driver for next generation BASE-T (NBASE-T). The increasing use of 10GbE on server ports drives need for 40GbE uplinks today and 100GbE uplinks for future networks.

Why twisted pair cabling? Not all access switches are top-of-rack that utilize 10GbE SFP+ direct attach copper cables or 40GbE QSFP+ cables for distances up to 7 meters. Twisted pair cabling provides flexibility in physical topology.

Twisted pair cabling enables top-of-rack, middle-of-row and end-of-row topologies with full port utilization and no stranded ports. Multiple speed generations are realized over compatible cabling infrastructure. Twisted pair cabling allows incremental upgrades in mixed environments. “Big pipes” are used only where you need them. Also, structured cabling provides for flexible moves/adds/changes.

What are some of the server market trends? It is a rapidly growing and changing environment with a variety of workloads and applications that need a different balance of compute vs. I/O capability. Some examples include the drive to increase the speed up to 1000x this decade for the high performance computing application. Another example is the growth of density optimized Servers for Internet Portal Datacenter (IPDC), cloud computing and social networking applications.

What is the forecast for 40G and 100G Ethernet for the server market? An updated forecast was presented as part of the CFI. In the 2012 to 2014 timeframe, 40G Ethernet represents less than 5% of the total x86 Server market for “fringe users” who demand the most possible bandwidth.

In the 2015 to 2017 timeframe, 40G Ethernet represents up to 20% of the total x86 Server market for “Performance users” who demand more I/O performance due to virtualization or, in some cases, the desire to converge the SAN and LAN networks within the rack.

In the 2018 to 2020 timeframe, 40G Ethernet represents up to 55% and 100G Ethernet represents up to 20% of the total x86 Server market. In that timeframe, a large portion of server buyers, designated as “free users” will implement 40GbE that is offered as the base configuration.

The CFI also discusses the Technical Viability of 40GbE transmission over twisted pair cabling. It was noted that both TIA and ISO/IEC are actively developing the specifications for the Next Generation Cabling and that the body of work so far shows that sufficient capacity exists for 40GbE over four twisted pairs.

Also, individuals from multiple semiconductor companies concur that NGBASE-T baseband circuits for 40GbE are viable in the time frame of this standard.

The building blocks are coming together and the work is starting. The IEEE NGBASE-T Study group topics include understanding reach vs. power trade-off, channel objectives, data rate, coding/ modulation and Energy Efficient Ethernet.

Although it is still some time in the future before the next generation BASE-T standard takes shape and is ratified, the timing is right and coincides with the market need for higher speed switch-to-server connections. It is also an exciting time for the cabling industry to build the components for a cabling highway that can support up to four times the bandwidth that is needed for 10 Gigabit Ethernet. CNS

Paul Kish is Director, Systems and Standards at Belden. The information presented is the author’s view and
is not official TIA correspondence.