|By Marten Terpstra||
|July 24, 2014 06:00 AM EDT||
In the past few weeks you may have seen several press releases and articles talking about 25 Gbit Ethernet. Just when you got used to ethernet speeds being a nice decimal based system where we simply add zeros every few years, someone threw in 40GbE a few years ago. And that’s ok, powers of two we can deal with, but 25? That just does not fit in our mental model of Ethernet.
The driving force behind 25GbE Ethernet is actually fairly simple and straightforward. If you open up an ethernet switch (small, large, does not really matter), you will find that all the high speed components are connected using serial links called SerDes, the rather boring concatenation of SERializer and DESerializer. The serializer is a piece of logic that takes data to be transferred and serializes it, the deserializer sits on the receiving side and reconstructs the serial stream of bits back into data for the ultimate receiver. Between the two, there are some basic encoding mechanisms to keep their clocks synchronized, some basic framing and a few other things. Google for 64B/66B encoding if you really want to understand the gory details.
Gigabit and 10Gigabit ethernet runs over these SerDes connections between components. In a typical 10GbE Top of Rack like switch, the Ethernet switching chip (everyone has heard of Trident2 as the market leading chipset in use today), the actual ethernet ports are SerDes connections coming from the chip (128 of them for Trident2, each representing a 10GbE equivalent port). These connections are then used to connect to other Ethernet of fabric chips (in the case of chassis based systems), or directly to the cages SFP+ and QSFP optics plug into. Communication between an SFP+ in the front of the switch and the switching chip runs on top of one of these SerDes connections.
As you probably figured out, the components used in today’s switches all run SerDes with a clock rate around 12.5Ghz, providing that 10Gbit transfer rate between the components across each (allowing for the encoding overhead). Until recently, that speed was about the state of the art to run these serial links across short distances (this is all inside of a single device) within acceptable signal loss and cross talk ranges. Signal integrity is not one of my strong points, so that’s about the best explanation I will give you.
10 to 40 to 100
With that 10Gbit building block we have created higher speed interfaces. When you look at a 40GbE interface, it is constructed out of 4 parallel SerDes links between the Ethernet chip and the QSFP pluggable. Even when leaving the QSFP onto fiber, it takes 4 parallel 10Gbit streams to transport this to the receiving QSFP. The short reach QSFP interfaces use 4 pair of fiber between them, and their copper Direct Attach Cable (DAC) equivalent carry the same on several copper cables inside the big cable. Longer reach QSFP interfaces put the 4 10Gbit streams onto separate Wave Division Multiplexing (WDM) waves which can be carried over a single pair of fiber. This is part of the reason why QSFP optics are fairly expensive still, especially for longer distances. Distribution of the bits across these parallel paths is done on almost a bit by bit basis by the hardware and has nothing to do with the packet based distribution we know in Ethernet.
Similarly for the 100GbE interfaces that are available today, these are really constructed out of 10 parallel paths of 10Gbit streams. Similar to the 40GbE example above, these are carried across 10 pair of fiber, or multiplexed together into a single fiber. Of course that also comes at a cost.
In the past 2-3 years, technology has advanced to the point that 25Ghz SerDes have become economically viable, and all of the usual physics problems in signal integrity have found solutions. This now means that we can push data 2.5 times as fast across those serial links, and ethernet chipsets due in the next year will start to have 25Ghz SerDes ports on them rather than 12.5Ghz ports. Once you have these ports, you can of course still run 10GbE across it, but you would not use all the capacity of that connection. 40GbE will then have the option to run across 2 parallel 25Ghz SerDes, rather than the 4 required today. And that translates into less cabling between devices. Similarly, 100GbE will move away from the current 10×10 implementations rather quickly to 4×25, for the very same reasons. Less parallel paths, less fibers, less optics, less everything.
Which then leaves the question, if there is this basic 25Ghz building block that we intend to use for 40GbE and 100GbE, why would we not want to use it in and by itself for 25GbE. As a single signal, it would provide a 2.5 performance boost in an SFP+ form factor without doing anything complicated. It’s like taking 10GbE and simply run it faster, one the hardest part has been solved, running a serial signal that fast.
And then there is 25
And there is your long winded but rather straightforward reason for 25Gbit Ethernet. Independent of ethernet, serial I/O technology has created an extremely useful building block that runs much faster than its predecessor. IEEE in its standardization of 100GbE already assumed 25Ghz serial I/O capabilities and has layered its definition of 100GbE on top it (the 10×10 available today is mostly a placeholder, make sure you ask your vendor what flavor of 100GbE they provide). But that same IEEE never went back to re-apply that 25Ghz technology to 10GbE and 40GbE and turn it into 25GbE and 50GbE. With lots of the foundational work done as part of the 100GbE specifications, this is not the tremendous 4-5 year effort that most IEEE standards efforts take.
The vendor industry has taken it on themselves to move this along outside of IEEE with a 25GbE consortium. There are several parts and components required to create complete 25GbE ethernet solutions. The ethernet chips will start to have them within a year, we then also need pluggable optics and perhaps even Direct Attach Cables to support the native 25GbE and its 50GbE sister, and of course server NIC cards need to support this as well. This is one of these efforts that requires a relatively small development across all of these components (emphasis on relatively) with a fairly quick 2.5x performance payoff at the end. As a consumer, 25GbE and 50GbE provide will provide you with a substantial performance boost in your datacenter server and storage environment with less cabling at a cost that in my opinion will get to small premiums over 10GbE fairly quickly over the next few years.
At Plexxi we fully support the 25GbE efforts, there is very little if anything negative associated with the push to productization. We will quickly embrace ethernet chipsets that support 25Ghz SerDes and the optical components that help us drive our optical fabric to higher capacities. The IEEE has always been the one and only standardization body for anything Ethernet, but it has been sent a clear message by the industry to move a lot faster. I have no doubt that that same industry will drive 25GbE to commercial success because it just makes sense.
[Today's fun fact: Over 50 percent of your body heat is lost through your head and neck. That is a very useful fact for us here in the Northeast.]
The post What is 25 Gigabit Ethernet and why would you want it? appeared first on Plexxi.
Some developers believe that monitoring is a function of the operations team. Some operations teams firmly believe that monitoring the systems they maintain is sufficient to run the business successfully. Most of them are wrong. The complexity of today's applications have gone far and beyond the capabilities of "traditional" system-level monitoring tools and approaches and requires much broader knowledge of business and applications as a whole. The goal of DevOps is to connect all aspects of app...
Nov. 27, 2014 12:00 PM EST Reads: 646
The 4th International DevOps Summit, co-located with16th International Cloud Expo – being held June 9-11, 2015, at the Javits Center in New York City, NY – announces that its Call for Papers is now open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's large...
Nov. 27, 2014 12:00 PM EST Reads: 1,585
15th Cloud Expo, which took place Nov. 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA, expanded the conference content of @ThingsExpo, Big Data Expo, and DevOps Summit to include two developer events. IBM held a Bluemix Developer Playground on November 5 and ElasticBox held a Hackathon on November 6. Both events took place on the expo floor. The Bluemix Developer Playground, for developers of all levels, highlighted the ease of use of Bluemix, its services and functionalit...
Nov. 27, 2014 12:00 PM EST Reads: 803
Want to enable self-service provisioning of application environments in minutes that mirror production? Can you automatically provide rich data with code-level detail back to the developers when issues occur in production? In his session at DevOps Summit, David Tesar, Microsoft Technical Evangelist on Microsoft Azure and DevOps, will discuss how to accomplish this and more utilizing technologies such as Microsoft Azure, Visual Studio online, and Application Insights in this demo-heavy session.
Nov. 27, 2014 11:45 AM EST Reads: 911
When an enterprise builds a hybrid IaaS cloud connecting its data center to one or more public clouds, security is often a major topic along with the other challenges involved. Security is closely intertwined with the networking choices made for the hybrid cloud. Traditional networking approaches for building a hybrid cloud try to kludge together the enterprise infrastructure with the public cloud. Consequently this approach requires risky, deep "surgery" including changes to firewalls, subnets...
Nov. 27, 2014 11:45 AM EST Reads: 896
DevOps is all about agility. However, you don't want to be on a high-speed bus to nowhere. The right DevOps approach controls velocity with a tight feedback loop that not only consists of operational data but also incorporates business context. With a business context in the decision making, the right business priorities are incorporated, which results in a higher value creation. In his session at DevOps Summit, Todd Rader, Solutions Architect at AppDynamics, discussed key monitoring techniques...
Nov. 27, 2014 11:30 AM EST Reads: 910
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
Nov. 27, 2014 11:00 AM EST Reads: 1,175
SYS-CON Media announced that Centrify, a provider of unified identity management across cloud, mobile and data center environments that delivers single sign-on (SSO) for users and a simplified identity infrastructure for IT, has launched an ad campaign on Cloud Computing Journal. The ads focus on security: how an organization can successfully control privilege for all of the organization’s identities to mitigate identity-related risk without slowing down the business, and how Centrify provides ...
Nov. 27, 2014 10:00 AM EST Reads: 1,263
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrateg...
Nov. 27, 2014 10:00 AM EST Reads: 1,137
"We help companies that are using a lot of Software as a Service. We help companies manage and gain visibility into what people are using inside the company and decide to secure them or use standards to lock down or to embrace the adoption of SaaS inside the company," explained Scott Kriz, Co-founder and CEO of Bitium, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 27, 2014 08:45 AM EST Reads: 1,193
"SAP had made a big transition into the cloud as we believe it has significant value for our customers, drives innovation and is easy to consume. When you look at the SAP portfolio, SAP HANA is the underlying platform and it powers all of our platforms and all of our analytics," explained Thorsten Leiduck, VP ISVs & Digital Commerce at SAP, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 27, 2014 08:15 AM EST Reads: 1,248
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device exp...
Nov. 27, 2014 08:00 AM EST Reads: 1,123
SAP is delivering break-through innovation combined with fantastic user experience powered by the market-leading in-memory technology, SAP HANA. In his General Session at 15th Cloud Expo, Thorsten Leiduck, VP ISVs & Digital Commerce, SAP, discussed how SAP and partners provide cloud and hybrid cloud solutions as well as real-time Big Data offerings that help companies of all sizes and industries run better. SAP launched an application challenge to award the most innovative SAP HANA and SAP HANA...
Nov. 27, 2014 08:00 AM EST Reads: 1,195
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps,...
Nov. 27, 2014 07:45 AM EST Reads: 1,443
"Cloud consumption is something we envision at Solgenia. That is trying to let the cloud spread to the user as a consumption, as utility computing. We want to allow the people to just pay for what they use, not a subscription model," explained Ermanno Bonifazi, CEO & Founder of Solgenia, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 27, 2014 07:15 AM EST Reads: 1,043