|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.
BMC Software plans to acquire assets of CDB Software, Inc., a mainframe data management company that has developed utilities for managing IBM DB2 databases with virtually no outage. Focusing on the availability of mission-critical applications is strategic for BMC as it continues to help its customers transform IT into a competitive advantage for their business. CDB's technology complements BMC's existing mainframe data management portfolio, which includes software utilities for DB2 administrat...
Jan. 29, 2015 07:00 AM EST Reads: 1,076
“DevOps is really about the business. The business is under pressure today, competitively in the marketplace to respond to the expectations of the customer. The business is driving IT and the problem is that IT isn't responding fast enough," explained Mark Levy, Senior Product Marketing Manager at Serena Software, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Jan. 29, 2015 06:00 AM EST Reads: 2,424
The 3rd International Internet of @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
Jan. 29, 2015 06:00 AM EST Reads: 7,908
“This win means a great deal to us because it is decided by the readers – the people who understand how use of our technology enables new insights that drive the business,” said Matt Davies, senior director, EMEA marketing, Splunk. “Splunk Enterprise enables organizations to improve service levels, reduce operations costs, mitigate security risks, enhance DevOps collaboration, create new product and service offerings and obtain deeper insight into customer behavior. Being named Best Business App...
Jan. 29, 2015 06:00 AM EST Reads: 2,048
"ElasticBox is an enterprise company that makes it very easy for developers and IT ops to collaborate to develop, build and deploy applications on any cloud - private, public or hybrid," stated Monish Sharma, VP of Customer Success at ElasticBox, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Jan. 29, 2015 05:00 AM EST Reads: 2,634
Today’s enterprise is being driven by disruptive competitive and human capital requirements to provide enterprise application access through not only desktops, but also mobile devices. To retrofit existing programs across all these devices using traditional programming methods is very costly and time consuming – often prohibitively so. In his session at @ThingsExpo, Jesse Shiah, CEO, President, and Co-Founder of AgilePoint Inc., discussed how you can create applications that run on all mobile ...
Jan. 29, 2015 05:00 AM EST Reads: 2,788
The move in recent years to cloud computing services and architectures has added significant pace to the application development and deployment environment. When enterprise IT can spin up large computing instances in just minutes, developers can also design and deploy in small time frames that were unimaginable a few years ago. The consequent move toward lean, agile, and fast development leads to the need for the development and operations sides to work very closely together. Thus, DevOps become...
Jan. 29, 2015 05:00 AM EST Reads: 2,698
In her General Session at 15th Cloud Expo, Anne Plese, Senior Consultant, Cloud Product Marketing, at Verizon Enterprise, focused on finding the right mix of renting vs. buying Oracle capacity to scale to meet business demands, and offer validated Oracle database TCO models for Oracle development and testing environments. Anne Plese is a marketing and technology enthusiast/realist with over 19+ years in high tech. At Verizon Enterprise, she focuses on driving growth for the Verizon Cloud platfo...
Jan. 29, 2015 04:30 AM EST Reads: 3,358
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series dat...
Jan. 29, 2015 03:45 AM EST Reads: 3,064
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...
Jan. 29, 2015 03:30 AM EST Reads: 2,682
Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, addressed the big issues involving these technologies and, more important, the results they will achieve. Rodney Rogers, chairman and CEO of Virtustream; Brendan O'Brien, co-founder of Aria Systems, Bart Copeland, president and CEO of ActiveState Software; Jim Cowie, chief scientist at Dyn; Dave Wagstaff, VP ...
Jan. 29, 2015 03:00 AM EST Reads: 2,716
SYS-CON Media announced that Splunk, a provider of the leading software platform for real-time Operational Intelligence, has launched an ad campaign on Big Data Journal. Splunk software and cloud services enable organizations to search, monitor, analyze and visualize machine-generated big data coming from websites, applications, servers, networks, sensors and mobile devices. The ads focus on delivering ROI - how improved uptime delivered $6M in annual ROI, improving customer operations by minin...
Jan. 29, 2015 02:15 AM EST Reads: 3,762
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using ...
Jan. 29, 2015 02:00 AM EST Reads: 2,960
Code Halos - aka "digital fingerprints" - are the key organizing principle to understand a) how dumb things become smart and b) how to monetize this dynamic. In his session at @ThingsExpo, Robert Brown, AVP, Center for the Future of Work at Cognizant Technology Solutions, outlined research, analysis and recommendations from his recently published book on this phenomena on the way leading edge organizations like GE and Disney are unlocking the Internet of Things opportunity and what steps your o...
Jan. 29, 2015 02:00 AM EST Reads: 2,992
In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect at GE, and Ibrahim Gokcen, who leads GE's advanced IoT analytics, focused on the Internet of Things / Industrial Internet and how to make it operational for business end-users. Learn about the challenges posed by machine and sensor data and how to marry it with enterprise data. They also discussed the tips and tricks to provide the Industrial Internet as an end-user consumable service using Big Data Analytics and Industrial C...
Jan. 29, 2015 01:00 AM EST Reads: 2,858