|By Marten Terpstra||
|April 18, 2014 09:15 AM EDT||
Earlier this week, Ethan Banks wrote a very nice article about Mellanox’s dual spine and leaf network in support of a large amount 10GbE access ports. After describing the scaled up network design, he reviews 8 observations about the design, not to point out good or bad, but merely to point out specific points to consider. Fully coincidental (Ethan lives close to us, but I am pretty sure he cannot peek through our windows) we had gone through a similar exercise this week, documenting the choices and limitations of spine and leaf networks. And as always, the conclusions are not ones of right or wrong, more of awareness of choices and consequences.
The Mellanox design Ethan describes employes an extra spine layer, we have seen and heard the same from Arista and others, some calling it a spine-spine or similar. Nitpicking perhaps, but adding a spine layer to a spine and leaf network and still calling it a spine and leaf network is like adding a docking station, screen and keyboard to a phone and still calling it a phone. It’s a computer that can make calls. And a spine and leaf network with an extra spine is a fat tree.
Ethan points out in his first few points that the sheer amount of cables and optics is astonishing. Let me try and put some numbers around that statement. If you build an approximate 3:1 oversubscribed spine and leaf network out of generic switches, I would probably use a Trident2 based ToR switch with 48 SFP+/10GbE ports and 6 QSFP/40GbE ports. The 48 ports should serve most rack deployments with single homed servers, only really dense or heavily multi homed servers would need more ports and I will use 4 of the QSFP ports to connect to my spine. That leaves 2 QSFPs on each leaf to be used for extra access ports, at the cost of some oversubscription. Or if I wanted I could use these as extra spine connections, lowering my oversubscription to 2:1. As a spine, and staying away from chassis based systems, I would pick a 32xQSFP/40GbE switch.
The largest spine and leaf I could build out of this combination is one that contains 16 spine switches and 96 leaf switches. In a spine and leaf I need to connect each leaf to each spine and I have the equivalent of 16x10GbE to use out of each leaf, which I can connect to at best 16 spines. With each spine receiving 1x10GbE from each leaf, I can build out to 96 leafs to fill out my 32xQSFP or 96x10GbE equivalent spine switch capacity. 96 Leaf switches give me 4608 10GbE access ports at 3:1 oversubscription, 5376 at a slightly worse oversubscription if I use the extra QSFP ports on my leaf switches. To support these 5376 access ports, I need 3584 10GbE fabric ports: 16 each from 96 leaf switches plus 32×4 from each spine. That means 1792 switch interconnect cables. And 3584 10GbE short reach optics, because the vast majority of connections between spines and leafs is likely to be at a distance that DAC cables cannot cover (not considering the fact that most high density 10GbE switches are designed without PHYs, limiting the use of passive cables to usually 5m or less).
I let you do the math on the cost of that infrastructure. And the installation. And the maintenance. And the sheer complexity of running a 10GbE from each leaf to each spine. If you want to reduce some of this complexity, you can switch to using 40GbE/QSFPs between the leafs and spines, but by doing so you have reduced the maximum size of the network. Each leaf will now contribute 1 QSFP worth of interconnect to each spine, to a 32xQSFP spine can only support 32 leaf switches, or 1536 10GbE access ports (1792 if you use the 2 extra leaf QSFP ports). And you probably noticed that I left no room on the spine switches to actually leave this spine and leaf network to the rest of the network infrastructure. Taking a few QSFPs for that will reduce the size of the network more.
Even in the spine, spine and leaf network (or spine, leaf and ToR in Mellanox terminology) the amount of cabling between the ToR (someone explain why that is not the leaf of the network?) and the aggregation leaf may be reduced, the cabling between their aggregation leaf and spine still follows the same model as above.
We often focus on the cost of switches and the derived cost per port. Of course the cost per port is important, but don’t fool yourself by taking the cost of a switch and dividing it by the number of ports it supports. It makes for great quotes in press releases, but the actual cost for that port is way higher the moment you add in the overhead required to connect that port to the rest of the network. And for spine and leaf networks, the cost of the rest of the network has a very large portion of cables and optics. Even for reasonably priced optics, that piece of the infrastructure is likely going to cost more than the cost of the spine switches together. Even when you create one of these multispined animals…
[Today's fun fact: The human spine contains 120 muscles and approximately 220 individual ligaments.]
The post There is cost per port and then there is cost per port… appeared first on Plexxi.
The revocation of Safe Harbor has radically affected data sovereignty strategy in the cloud. In his session at 17th Cloud Expo, Jeff Miller, Product Management at Cavirin Systems, discussed how to assess these changes across your own cloud strategy, and how you can mitigate risks previously covered under the agreement.
Nov. 30, 2015 03:56 PM EST
Countless business models have spawned from the IaaS industry – resell Web hosting, blogs, public cloud, and on and on. With the overwhelming amount of tools available to us, it's sometimes easy to overlook that many of them are just new skins of resources we've had for a long time. In his general session at 17th Cloud Expo, Harold Hannon, Sr. Software Architect at SoftLayer, an IBM Company, broke down what we have to work with, discussed the benefits and pitfalls and how we can best use them ...
Nov. 30, 2015 03:45 PM EST
Most of the IoT Gateway scenarios involve collecting data from machines/processing and pushing data upstream to cloud for further analytics. The gateway hardware varies from Raspberry Pi to Industrial PCs. The document states the process of allowing deploying polyglot data pipelining software with the clear notion of supporting immutability. In his session at @ThingsExpo, Shashank Jain, a development architect for SAP Labs, discussed the objective, which is to automate the IoT deployment proces...
Nov. 30, 2015 03:30 PM EST
We all know that data growth is exploding and storage budgets are shrinking. Instead of showing you charts on about how much data there is, in his General Session at 17th Cloud Expo, Scott Cleland, Senior Director of Product Marketing at HGST, showed how to capture all of your data in one place. After you have your data under control, you can then analyze it in one place, saving time and resources.
Nov. 30, 2015 03:15 PM EST Reads: 242
The Internet of Things (IoT) is growing rapidly by extending current technologies, products and networks. By 2020, Cisco estimates there will be 50 billion connected devices. Gartner has forecast revenues of over $300 billion, just to IoT suppliers. Now is the time to figure out how you’ll make money – not just create innovative products. With hundreds of new products and companies jumping into the IoT fray every month, there’s no shortage of innovation. Despite this, McKinsey/VisionMobile data...
Nov. 30, 2015 03:00 PM EST Reads: 492
Just over a week ago I received a long and loud sustained applause for a presentation I delivered at this year’s Cloud Expo in Santa Clara. I was extremely pleased with the turnout and had some very good conversations with many of the attendees. Over the next few days I had many more meaningful conversations and was not only happy with the results but also learned a few new things. Here is everything I learned in those three days distilled into three short points.
Nov. 30, 2015 02:00 PM EST Reads: 366
As organizations realize the scope of the Internet of Things, gaining key insights from Big Data, through the use of advanced analytics, becomes crucial. However, IoT also creates the need for petabyte scale storage of data from millions of devices. A new type of Storage is required which seamlessly integrates robust data analytics with massive scale. These storage systems will act as “smart systems” provide in-place analytics that speed discovery and enable businesses to quickly derive meaningf...
Nov. 30, 2015 01:45 PM EST Reads: 434
DevOps is about increasing efficiency, but nothing is more inefficient than building the same application twice. However, this is a routine occurrence with enterprise applications that need both a rich desktop web interface and strong mobile support. With recent technological advances from Isomorphic Software and others, rich desktop and tuned mobile experiences can now be created with a single codebase – without compromising functionality, performance or usability. In his session at DevOps Su...
Nov. 30, 2015 01:45 PM EST Reads: 430
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
Nov. 30, 2015 01:00 PM EST Reads: 537
In his General Session at 17th Cloud Expo, Bruce Swann, Senior Product Marketing Manager for Adobe Campaign, explored the key ingredients of cross-channel marketing in a digital world. Learn how the Adobe Marketing Cloud can help marketers embrace opportunities for personalized, relevant and real-time customer engagement across offline (direct mail, point of sale, call center) and digital (email, website, SMS, mobile apps, social networks, connected objects).
Nov. 30, 2015 12:45 PM EST Reads: 342
The buzz continues for cloud, data analytics and the Internet of Things (IoT) and their collective impact across all industries. But a new conversation is emerging - how do companies use industry disruption and technology enablers to lead in markets undergoing change, uncertainty and ambiguity? Organizations of all sizes need to evolve and transform, often under massive pressure, as industry lines blur and merge and traditional business models are assaulted and turned upside down. In this new da...
Nov. 30, 2015 12:45 PM EST Reads: 288
In recent years, at least 40% of companies using cloud applications have experienced data loss. One of the best prevention against cloud data loss is backing up your cloud data. In his General Session at 17th Cloud Expo, Sam McIntyre, Partner Enablement Specialist at eFolder, presented how organizations can use eFolder Cloudfinder to automate backups of cloud application data. He also demonstrated how easy it is to search and restore cloud application data using Cloudfinder.
Nov. 30, 2015 11:00 AM EST Reads: 218
The Internet of Everything is re-shaping technology trends–moving away from “request/response” architecture to an “always-on” Streaming Web where data is in constant motion and secure, reliable communication is an absolute necessity. As more and more THINGS go online, the challenges that developers will need to address will only increase exponentially. In his session at @ThingsExpo, Todd Greene, Founder & CEO of PubNub, exploreed the current state of IoT connectivity and review key trends and t...
Nov. 30, 2015 10:45 AM EST Reads: 462
Two weeks ago (November 3-5), I attended the Cloud Expo Silicon Valley as a speaker, where I presented on the security and privacy due diligence requirements for cloud solutions. Cloud security is a topical issue for every CIO, CISO, and technology buyer. Decision-makers are always looking for insights on how to mitigate the security risks of implementing and using cloud solutions. Based on the presentation topics covered at the conference, as well as the general discussions heard between sessi...
Nov. 30, 2015 10:30 AM EST Reads: 354
With all the incredible momentum behind the Internet of Things (IoT) industry, it is easy to forget that not a single CEO wakes up and wonders if “my IoT is broken.” What they wonder is if they are making the right decisions to do all they can to increase revenue, decrease costs, and improve customer experience – effectively the same challenges they have always had in growing their business. The exciting thing about the IoT industry is now these decisions can be better, faster, and smarter. Now ...
Nov. 30, 2015 10:00 AM EST Reads: 291