Welcome!

Linux Authors: Liz McMillan, Elizabeth White, Shelly Palmer, Carmen Gonzalez, Jim Kaskade

Related Topics: SDN Journal, Java, Linux, Virtualization

SDN Journal: Blog Post

There Is Cost Per Port and Then There Is Cost Per Port…

I let you do the math on the cost of that infrastructure. And the installation. And the maintenance

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.

Read the original blog entry...

More Stories By Marten Terpstra

Marten Terpstra is a Product Management Director at Plexxi Inc. Marten has extensive knowledge of the architecture, design, deployment and management of enterprise and carrier networks.

@ThingsExpo Stories
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.
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
The Internet of Things (IoT) is going to require a new way of thinking and of developing software for speed, security and innovation. This requires IT leaders to balance business as usual while anticipating for the next market and technology trends. Cloud provides the right IT asset portfolio to help today’s IT leaders manage the old and prepare for the new. Today the cloud conversation is evolving from private and public to hybrid. This session will provide use cases and insights to reinforce the value of the network in helping organizations to maximize their company’s cloud experience.
Disruptive macro trends in technology are impacting and dramatically changing the "art of the possible" relative to supply chain management practices through the innovative use of IoT, cloud, machine learning and Big Data to enable connected ecosystems of engagement. Enterprise informatics can now move beyond point solutions that merely monitor the past and implement integrated enterprise fabrics that enable end-to-end supply chain visibility to improve customer service delivery and optimize supplier management. Learn about enterprise architecture strategies for designing connected systems tha...
IoT is still a vague buzzword for many people. In his session at Internet of @ThingsExpo, Mike Kavis, Vice President & Principal Cloud Architect at Cloud Technology Partners, will discuss the business value of IoT that goes far beyond the general public's perception that IoT is all about wearables and home consumer services. The presentation will also discuss how IoT is perceived by investors and how venture capitalist access this space. Other topics to discuss are barriers to success, what is new, what is old, and what the future may hold.
Whether you're a startup or a 100 year old enterprise, the Internet of Things offers a variety of new capabilities for your business. IoT style solutions can help you get closer your customers, launch new product lines and take over an industry. Some companies are dipping their toes in, but many have already taken the plunge, all while dramatic new capabilities continue to emerge. In his session at Internet of @ThingsExpo, Reid Carlberg, Senior Director, Developer Evangelism at salesforce.com, to discuss real-world use cases, patterns and opportunities you can harness today.
All major researchers estimate there will be tens of billions devices – computers, smartphones, tablets, and sensors – connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be!
Noted IoT expert and researcher Joseph di Paolantonio (pictured below) has joined the @ThingsExpo faculty. Joseph, who describes himself as an “Independent Thinker” from DataArchon, will speak on the topic of “Smart Grids & Managing Big Utilities.” Over his career, Joseph di Paolantonio has worked in the energy, renewables, aerospace, telecommunications, and information technology industries. His expertise is in data analysis, system engineering, Bayesian statistics, data warehouses, business intelligence, data mining, predictive methods, and very large databases (VLDB). Prior to DataArcho...
Software AG helps organizations transform into Digital Enterprises, so they can differentiate from competitors and better engage customers, partners and employees. Using the Software AG Suite, companies can close the gap between business and IT to create digital systems of differentiation that drive front-line agility. We offer four on-ramps to the Digital Enterprise: alignment through collaborative process analysis; transformation through portfolio management; agility through process automation and integration; and visibility through intelligent business operations and big data.
There will be 50 billion Internet connected devices by 2020. Today, every manufacturer has a propriety protocol and an app. How do we securely integrate these "things" into our lives and businesses in a way that we can easily control and manage? Even better, how do we integrate these "things" so that they control and manage each other so our lives become more convenient or our businesses become more profitable and/or safe? We have heard that the best interface is no interface. In his session at Internet of @ThingsExpo, Chris Matthieu, Co-Founder & CTO at Octoblu, Inc., will discuss how thes...
Last week, while in San Francisco, I used the Uber app and service four times. All four experiences were great, although one of the drivers stopped for 30 seconds and then left as I was walking up to the car. He must have realized I was a blogger. None the less, the next car was just a minute away and I suffered no pain. In this article, my colleague, Ved Sen, Global Head, Advisory Services Social, Mobile and Sensors at Cognizant shares his experiences and insights.
We are reaching the end of the beginning with WebRTC and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will want to use their existing identities, but these will have credentials already that are (hopefully) ir...
Can call centers hang up the phones for good? Intuitive Solutions did. WebRTC enabled this contact center provider to eliminate antiquated telephony and desktop phone infrastructure with a pure web-based solution, allowing them to expand beyond brick-and-mortar confines to a home-based agent model. It also ensured scalability and better service for customers, including MUY! Companies, one of the country's largest franchise restaurant companies with 232 Pizza Hut locations. This is one example of WebRTC adoption today, but the potential is limitless when powered by IoT. Attendees will learn rea...
From telemedicine to smart cars, digital homes and industrial monitoring, the explosive growth of IoT has created exciting new business opportunities for real time calls and messaging. In his session at Internet of @ThingsExpo, Ivelin Ivanov, CEO and Co-Founder of Telestax, will share some of the new revenue sources that IoT created for Restcomm – the open source telephony platform from Telestax. Ivelin Ivanov is a technology entrepreneur who founded Mobicents, an Open Source VoIP Platform, to help create, deploy, and manage applications integrating voice, video and data. He is the co-founder ...
The Internet of Things (IoT) promises to create new business models as significant as those that were inspired by the Internet and the smartphone 20 and 10 years ago. What business, social and practical implications will this phenomenon bring? That's the subject of "Monetizing the Internet of Things: Perspectives from the Front Lines," an e-book released today and available free of charge from Aria Systems, the leading innovator in recurring revenue management.
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.
There’s Big Data, then there’s really Big Data from the Internet of Things. IoT is evolving to include many data possibilities like new types of event, log and network data. The volumes are enormous, generating tens of billions of logs per day, which raise data challenges. Early IoT deployments are relying heavily on both the cloud and managed service providers to navigate these challenges. In her session at 6th Big Data Expo®, Hannah Smalltree, Director at Treasure Data, to discuss how IoT, Big Data and deployments are processing massive data volumes from wearables, utilities and other mach...
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at Internet of @ThingsExpo, Erik Lagerway, Co-founder of Hookflash, will walk through the shifting landscape of traditional telephone and voice s...
While great strides have been made relative to the video aspects of remote collaboration, audio technology has basically stagnated. Typically all audio is mixed to a single monaural stream and emanates from a single point, such as a speakerphone or a speaker associated with a video monitor. This leads to confusion and lack of understanding among participants especially regarding who is actually speaking. Spatial teleconferencing introduces the concept of acoustic spatial separation between conference participants in three dimensional space. This has been shown to significantly improve comprehe...
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, will discuss single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example...