Welcome!

@CloudExpo Authors: Pat Romanski, Elizabeth White, Liz McMillan, Jim Hansen, ManageEngine IT Matters

Blog Feed Post

It's On: Stacks versus Flows

#OpenStack #CloudStack #OpenFlow #SDN It's a showdown of model versus control – or is it?

 

stack-vs-flow

There's a lot of noise about "wars" in the networking world these days. OpenStack versus CloudStack versus OpenFlow-based SDN.

But while there are definitely aspects of "stacks" that share similarities with "flows", they are not the same model and ultimately they aren't even necessarily attempting to solve the same problems.

Understanding the two models and what they're intended to do can go a long way toward resolving any perceived conflicts.

The Stack Model

Stack models, such as CloudStack and OpenStack, are more accurately placed in the category of "cloud management frameworks" because they are designed with provisioning and management of the infrastructure services that comprise a cloud computing (or highly dynamic) environment.

Stacks are aptly named as they attempt to provide management and specifically automation of provisioning for the complete network stack. Both CloudStack and OpenStack, along with Eucalyptus and Amazon and VMware vCloud, provide a framework API that can (ostensibly) be used to provision infrastructure services irrespective of vendor implementation. The vision is (or should be) to enable implementers (whether service provider or enterprise) to be able to switch out architectural elements (routers, switches, hypervisors, load balancers, etc… ) transparently*. That is, moving from Dell to HP to Cisco (or vice-versa) as an environment's switching fabric should not be disruptive. Physical changes should be able to occur without impacting the provisioning and management of the actual services provided by the infrastructure.

And yes, such a strategy should also allow heterogeneity of infrastructure.

In many ways, such "stacks" are the virtualization of the data center, enabling abstraction of the actual implementation from the configuration and automation of the hardware (or software) elements. This, more than anything, is what enables a comparison with flow-based models.

The Flow Model

Flow-based models, in particular OpenFlow-based SDN, also abstracts implementation from configuration by decoupling the control plane from the data plane. This allows any OpenFlow-enabled device (mostly switches today, as SDN and OpenFlow focus on network layers) to be configured and managed via a centralized controller using a common API.

Flows are "installed" or "inserted" into OpenFlow-enabled elements via OpenFlow, an open protocol designed for this purpose, and support real-time updates that enable on-demand optimization or fault isolation of flows through the network. OpenFlow and SDN are focused on managing the flow of traffic through a network. 

Flow-based models purport to offer the same benefits as a stack model in terms of heterogeneity and interoperability. Moving from one OpenFlow-enabled switch to another (or mixing and matching) should ostensibly have no impact on the network whatsoever.

What flow-based models offer above and beyond a stack model is extensibility. OpenFlow-based SDN models using a centralized controller also carry with it the premise of being able to programmatically add new services to the network without vendor assistance. "Applications" deployed on an SDN controller platform (for lack of a better term) can extend existing services or add new ones and there is no need to change anything in the network fabric, because ultimately every "application" distills flows into a simple forwarding decision that can then be applied like a pattern to future flows by the switches.

The Differences

This is markedly different from the focus of a stack, which is on provisioning and management, even though both may be occurring in real-time. While it's certainly the case that through the CloudStack API you can create or delete port forwarding rules on a firewall, these actions are pushed (initiated) external to the firewall. It is not the case that the firewall receives a packet and asks the cloud framework for the appropriate action, which is the model in play for a switch in an OpenFlow-based SDN.

Another (relatively unmentioned but important) distinction is who bears responsibility for integration. A stack-based model puts the onus on the stack to integrate (via what are usually called "plug-ins" or "drivers") with the component's existing API (assuming one exists). A flow-based model requires the vendor to take responsibility for enabling OpenFlow support natively. Obviously the ecosystem of available resources to perform integration is a magnitude higher with a stack model than with a flow model. While vendors are involved in development of drivers/plug-ins for stacks now, the impact on the product itself is minimal, if any at all, because the integration occurs external to the component. Enabling native OpenFlow support on components requires a lot more internal resources be directed at such a project.

Do these differences make for an either-or choice?

Actually, they don't. The models are not mutually exclusive and, in fact, might be used in conjunction with one another quite well. A stack based approach to provisioning and management might well be complemented by an OpenFlow SDN in which flows through the network can be updated in real time or, as is often proffered as a possibility, the deployment of new protocols or services within the network.

The War that Isn't

While there certainly may be a war raging amongst the various stack models, it doesn't appear that a war between OpenFlow and *-Stack is something that's real or ever will be The two foci are very different, and realistically the two could easily be deployed in the same network and solve multiple problems. Network resources may be provisioned and initially configured via a stack but updated in real-time or extended by an SDN controller, assuming such network resources were OpenFlow-enabled in the first place.

 

* That's the vision (and the way it should be) at least. Reality thus far is that the OpenStack API doesn't support most network elements above L3 yet, and CloudStack is tightly coupling API calls to components, rendering this alleged benefit well, not a benefit at all, at least at L4 and above. 


Read the original blog entry...

More Stories By Lori MacVittie

Lori MacVittie is responsible for education and evangelism of application services available across F5’s entire product suite. Her role includes authorship of technical materials and participation in a number of community-based forums and industry standards organizations, among other efforts. MacVittie has extensive programming experience as an application architect, as well as network and systems development and administration expertise. Prior to joining F5, MacVittie was an award-winning Senior Technology Editor at Network Computing Magazine, where she conducted product research and evaluation focused on integration with application and network architectures, and authored articles on a variety of topics aimed at IT professionals. Her most recent area of focus included SOA-related products and architectures. She holds a B.S. in Information and Computing Science from the University of Wisconsin at Green Bay, and an M.S. in Computer Science from Nova Southeastern University.

@CloudExpo Stories
WebRTC sits at the intersection between VoIP and the Web. As such, it poses some interesting challenges for those developing services on top of it, but also for those who need to test and monitor these services. In his session at WebRTC Summit, Tsahi Levent-Levi, co-founder of testRTC, reviewed the various challenges posed by WebRTC when it comes to testing and monitoring and on ways to overcome them.
In his General Session at 16th Cloud Expo, David Shacochis, host of The Hybrid IT Files podcast and Vice President at CenturyLink, investigated three key trends of the “gigabit economy" though the story of a Fortune 500 communications company in transformation. Narrating how multi-modal hybrid IT, service automation, and agile delivery all intersect, he will cover the role of storytelling and empathy in achieving strategic alignment between the enterprise and its information technology.
"A lot of times people will come to us and have a very diverse set of requirements or very customized need and we'll help them to implement it in a fashion that you can't just buy off of the shelf," explained Nick Rose, CTO of Enzu, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? In this Power Panel at DevOps Summit, moderated by Jason Bloomberg, the leading expert on architecting agility for the enterprise and president of Intellyx, panelists peeled away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud enviro...
Containers have changed the mind of IT in DevOps. They enable developers to work with dev, test, stage and production environments identically. Containers provide the right abstraction for microservices and many cloud platforms have integrated them into deployment pipelines. DevOps and containers together help companies achieve their business goals faster and more effectively. In his session at DevOps Summit, Ruslan Synytsky, CEO and Co-founder of Jelastic, reviewed the current landscape of Dev...
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
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...
Cloud Expo, Inc. has announced today that Andi Mann returns to 'DevOps at Cloud Expo 2017' as Conference Chair The @DevOpsSummit at Cloud Expo will take place on June 6-8, 2017, at the Javits Center in New York City, NY. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited to help the great t...
WebRTC services have already permeated corporate communications in the form of videoconferencing solutions. However, WebRTC has the potential of going beyond and catalyzing a new class of services providing more than calls with capabilities such as mass-scale real-time media broadcasting, enriched and augmented video, person-to-machine and machine-to-machine communications. In his session at @ThingsExpo, Luis Lopez, CEO of Kurento, introduced the technologies required for implementing these idea...
Every successful software product evolves from an idea to an enterprise system. Notably, the same way is passed by the product owner's company. In his session at 20th Cloud Expo, Oleg Lola, CEO of MobiDev, will provide a generalized overview of the evolution of a software product, the product owner, the needs that arise at various stages of this process, and the value brought by a software development partner to the product owner as a response to these needs.
The WebRTC Summit New York, to be held June 6-8, 2017, at the Javits Center in New York City, NY, announces that its Call for Papers is now open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 20th International Cloud Expo and @ThingsExpo. WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web co...
SYS-CON Events announced today that Enzu will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Enzu’s mission is to be the leading provider of enterprise cloud solutions worldwide. Enzu enables online businesses to use its IT infrastructure to their competitive ad...
SYS-CON Events announced today that Catchpoint Systems, Inc., a provider of innovative web and infrastructure monitoring solutions, has been named “Silver Sponsor” of SYS-CON's DevOps Summit at 18th Cloud Expo New York, which will take place June 7-9, 2016, at the Javits Center in New York City, NY. Catchpoint is a leading Digital Performance Analytics company that provides unparalleled insight into customer-critical services to help consistently deliver an amazing customer experience. Designed ...
Internet of @ThingsExpo, taking place June 6-8, 2017 at the Javits Center in New York City, New York, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @ThingsExpo New York Call for Papers is now open.
Who are you? How do you introduce yourself? Do you use a name, or do you greet a friend by the last four digits of his social security number? Assuming you don’t, why are we content to associate our identity with 10 random digits assigned by our phone company? Identity is an issue that affects everyone, but as individuals we don’t spend a lot of time thinking about it. In his session at @ThingsExpo, Ben Klang, Founder & President of Mojo Lingo, discussed the impact of technology on identity. Sho...
Technology vendors and analysts are eager to paint a rosy picture of how wonderful IoT is and why your deployment will be great with the use of their products and services. While it is easy to showcase successful IoT solutions, identifying IoT systems that missed the mark or failed can often provide more in the way of key lessons learned. In his session at @ThingsExpo, Peter Vanderminden, Principal Industry Analyst for IoT & Digital Supply Chain to Flatiron Strategies, will focus on how IoT depl...
Data is an unusual currency; it is not restricted by the same transactional limitations as money or people. In fact, the more that you leverage your data across multiple business use cases, the more valuable it becomes to the organization. And the same can be said about the organization’s analytics. In his session at 19th Cloud Expo, Bill Schmarzo, CTO for the Big Data Practice at Dell EMC, introduced a methodology for capturing, enriching and sharing data (and analytics) across the organization...
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 ...
WebRTC is about the data channel as much as about video and audio conferencing. However, basically all commercial WebRTC applications have been built with a focus on audio and video. The handling of “data” has been limited to text chat and file download – all other data sharing seems to end with screensharing. What is holding back a more intensive use of peer-to-peer data? In her session at @ThingsExpo, Dr Silvia Pfeiffer, WebRTC Applications Team Lead at National ICT Australia, looked at differ...
"Splunk basically takes machine data and we make it usable, valuable and accessible for everyone. The way that plays in DevOps is - we need to make data-driven decisions to delivering applications," explained Andi Mann, Chief Technology Advocate at Splunk and @DevOpsSummit Conference Chair, in this SYS-CON.tv interview at @DevOpsSummit at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.