Part 1: Considering the state of 100G and the state we’re in

The past year slipped by at a dizzying pace for us at ESnet, as we made new forays into cutting-edge technologies. In this two-part blogpost, we will recap accomplishments of the year, but also consider the challenges facing us in the one to come as we progress towards delivering the Advanced Networking Initiative.

Stimulating 100G

One of our prime directives with ANI funding was to stimulate the 100G market towards increasing spectral efficiency. In the last year, we have had wonderful engagement with the vendors that are moving products in this direction. Coherent receivers and DP-QPSK modulation are now standard fare for the 40G/100G solutions. At the latest conference, IEEE ANTS, in Mumbai last week, the 100G question was considered solved. Researchers are now exploring innovative solutions to deliver a next generation of 100G with higher power efficiency, or jump to the next level in delivering 400G. One researcher at the Indian Institute of Technology, Mumbai, is looking at revolutionizing the power consumption curve of the digital processing paradigm of coherent solutions by investigating analog processing techniques (super secret, so we will just have to wait and see).

A representative from OFS, the optical fiber company, described research on new fibers which cater to the coherent world that will enable better performance. He quoted hero experiments, papers, and research presented at this years’ OFC, touting the advantages of new fiber captured through the joint work of Alcatel-Lucent Bell Labs and OFS (ex-Lucent) research collaborators. There is a lot of fiber still being laid out in the developing countries and they are well positioned to take advantage of this new research to bring cheaper broadband connectivity in so far underserved communities.

Some selected points raised at the panel regarding 400G and beyond:

• Raman amplification is coming back in vogue
• 50GHz ITU-Grid needs to evolve to flexi-grid technology. With flexi-grid, some of the basic modem concepts of negotiation (remember the auto-sensing modems of late 90’s) is back – where based on distance, and loss, the appropriate grid spacing can be negotiated for each wavelength.
• If the industry sticks with electrical compensation, optical equipment will see increased electricity consumption by the power-hungry Analog-Digital Conversion (ADC) and Digital Signal Processing (DSP) ASICS. With advances in CMOS, the status quo might not suffice in a few years, especially since the whole industry is out there sticking the router vendors with a big “power-hungry” sticker. The equations in power-consumption tradeoffs still need to be studied and appropriate comparisons made. I hope the vendors also develop a perspective in that direction.
• Comcast, the only other vendor on the panel, mentioned current capacities of 30x40G (coherent) on some links of their backbone and their eagerness to deploy 100G solutions. They are WAY ahead in deploying 100G, though the industry seems to not broadcast such news widely.
• Comcast felt that coherent optics in the Metro Area is overkill and entreated the vendors not to build one-size-fits-all solutions even if simpler (and, they hope making 100G more affordable, as well).

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  There was little discussion on the 100GE standards, although there was a clear message that LR-10 is here to stay, mainly supported by Data Center customers, though almost all traditional carriers intend deploy LR-4, in the case it starts costing less than a Ferrari.

At Supercomputing 2010, the SCinet community orchestrated and deployed 100G-capable equipment from Brocade, Cisco, Ciena and Juniper, to name a few vendors, and included 100G host demonstrations of data transfers by NASA. It was encouraging to see the Academic and R&E community lead deployment and testing of 100G [See a sample poster below].

The SCinet community lives on the “bleeding edge” and supported a demonstration by Internet2, ESnet, and other partners carrying live 100Gbps application data over a 100G wave from Chicago to New Orleans show floor.

We are looking forward to Seattle (SC11) and can already predict multiple 100G’s of bandwidth coming towards the show floor – if you have any cool demonstrations that you would like to collaborate with us, please drop us a note.

— Inder Monga