Welcome!

SDN Journal Authors: Pat Romanski, Destiny Bertucci, Liz McMillan, Elizabeth White, Amitabh Sinha

Related Topics: @ThingsExpo, Java IoT, @CloudExpo, @DXWorldExpo, SDN Journal, FinTech Journal

@ThingsExpo: Blog Feed Post

PubSub and Other Disruptive Emerging Network Models

What's new with software-defined architectures is not just the logical separation but the physical decoupling

When people write about software-defined architectures being "disruptive" to the network they're doing a bit of a disservice to just how much change is occurring under the hood in the engine that drives today's businesses. The notion of separating control and data planes is superficial in that it describes a general concept and it isn't really all that radical a change, if you think about it.

The control and data planes have always been separate. We have, since the need for web-scale networks came about, implemented separate topological (and usually physical) networks specifically for the purpose of segregating control traffic from the data path. The reasons for this are many: to keep management (control) traffic from interfering with the delivery of applications (and vice versa), to enable a model in which control over the critical path for applications could be secured and to ensure access to necessary control functions in the face of failure or attack.

What's new with software-defined architectures is not just the logical separation but the physical decoupling and change in component responsibility. In traditional networks there is a logically separate control plane, but it is distributed; it resides on each physical component. In software-defined networks it is physically separate but it is centralized; control responsibility resides in a single component, the "controller".

Now, OpenStack and emerging models for scaling systems that will be responsible for managing communication with and for the Internet of Things (like MQTT) use a similar control model, but it's not as active as a software-defined architectural model, it's more a passive model. That's the nature of PubSub imposing itself on the network.

PubSub Control Modelpubsub-model

PubSub (publish / subscribe) is a familiar model to application developers. It's a middleware staple that's been used for a very long time to distribute messages to a variable set of systems. In a nutshell, PubSub is based on the notion of there existing a "queue" to which authorized components can publish events or messages of interest and to which interested components an subscribe. Events or messages have a life (like a TTL) and eventually expire. In the interim, it's expected that subscribed components check the queue for messages periodically. They poll for events or messages.

The queue itself is much like a switch or router's queue, except messages in the queue are duplicated until the TTL runs out and the message expires.

PubSub is passive; that is, it does not actively distribute messages. It merely serves as a kind of centralized repository, making available to those components that need it access to relevant information about the state of applications and/or the network.

Centralized Control Model

push-modelOpenFlow-based SDN, by contrast, is active. That is, it not only serves as a centralized repository for the state of applications and/or the network, but it actively distributes messages to components based on events. For example, a controller might receive a message from another system indicating the launch of a new application instance. That event triggers a series of actions on the controller that includes informing the affected network components of configuration changes. In a passive, PubSub model, the network components themselves might be polling for such an event and, upon receiving one, would initiate the appropriate configuration changes themselves.

We can simplify the description of the differences even more: a controller-based architecture uses a push model, while a pubsub-based architecture uses a pull model. What this doesn't illustrate well is that in a push model, the centralized controller must know how to communicate the desired changes to each and every component it is controlling. That's one of the reasons original models standardized on OpenFlow and were tightly focused on L2-4 stateless networking. It could be easily standardized down to a common forwarding table.While different components might internalize that differently, the basic information was always the same: IP addresses, ports and actions.

As we move up the stack into L4-7 stateful networking, however, this model becomes more burdensome because of the complexity of rule sets and differences in policy models across such a broad set of networking domains. Hence the plug-in support in controllers like OpenDaylight for "other" control protocols. But the basic premise of the model remains the same, regardless of the control protocol: the centralized controller dictates the changes to all components. It pushes those changes to the network. Both control and execution are centralized. The controller tells components to change their configuration.

PubSub centralizes control but decentralizes execution. The control plane is still centralized; there is one authoritative system responsible for disseminating change across the network, but each individual component (or domain controller but we'll get to that in a minute) is responsible for executing the appropriate changes based on their configured policies and services. A pubsub controller never tells a component "change this now"; that's up to the individual components (or domain controller).

The Integrated Control Model

To make things even more confusing (and disruptive), these models may be used simultaneously. A software-defined architecture might be based on a centralized control model with domain controllers for specific networking functions (like security and application delivery) integrated via a pubsub-based model.

integrated-model

This is where we start seeing models that combine emerging technologies like OpenStack and SDN architectures together. OpenStack manages at the data center level, and at its heart is pubsub model that can be used by domain controllers (stateless L2-4 SDN, stateful L4-7 SDN, etc...) to receive notification of changes in the network and subsequently push those changes using the appropriate control protocols to the components it is managing.

Needless to say, the term "disruptive" is really inadequate in describing the level of change in the network required to support either models (or both). Both require significant changes not just to the network itself but the way in which the network is fundamentally provisioned and managed. It's not just a new CLI or management console, these models dramatically change the design and management of networks.

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
Cloud Expo | DXWorld Expo have announced the conference tracks for Cloud Expo 2018. Cloud Expo will be held June 5-7, 2018, at the Javits Center in New York City, and November 6-8, 2018, at the Santa Clara Convention Center, Santa Clara, CA. Digital Transformation (DX) is a major focus with the introduction of DX Expo within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive ov...
Mobile device usage has increased exponentially during the past several years, as consumers rely on handhelds for everything from news and weather to banking and purchases. What can we expect in the next few years? The way in which we interact with our devices will fundamentally change, as businesses leverage Artificial Intelligence. We already see this taking shape as businesses leverage AI for cost savings and customer responsiveness. This trend will continue, as AI is used for more sophistica...
In his session at 21st Cloud Expo, Raju Shreewastava, founder of Big Data Trunk, provided a fun and simple way to introduce Machine Leaning to anyone and everyone. He solved a machine learning problem and demonstrated an easy way to be able to do machine learning without even coding. Raju Shreewastava is the founder of Big Data Trunk (www.BigDataTrunk.com), a Big Data Training and consulting firm with offices in the United States. He previously led the data warehouse/business intelligence and B...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
In his general session at 21st Cloud Expo, Greg Dumas, Calligo’s Vice President and G.M. of US operations, discussed the new Global Data Protection Regulation and how Calligo can help business stay compliant in digitally globalized world. Greg Dumas is Calligo's Vice President and G.M. of US operations. Calligo is an established service provider that provides an innovative platform for trusted cloud solutions. Calligo’s customers are typically most concerned about GDPR compliance, application p...
Digital transformation is about embracing digital technologies into a company's culture to better connect with its customers, automate processes, create better tools, enter new markets, etc. Such a transformation requires continuous orchestration across teams and an environment based on open collaboration and daily experiments. In his session at 21st Cloud Expo, Alex Casalboni, Technical (Cloud) Evangelist at Cloud Academy, explored and discussed the most urgent unsolved challenges to achieve f...
Continuous Delivery makes it possible to exploit findings of cognitive psychology and neuroscience to increase the productivity and happiness of our teams. In his session at 22nd Cloud Expo | DXWorld Expo, Daniel Jones, CTO of EngineerBetter, will answer: How can we improve willpower and decrease technical debt? Is the present bias real? How can we turn it to our advantage? Can you increase a team’s effective IQ? How do DevOps & Product Teams increase empathy, and what impact does empath...
DevOps promotes continuous improvement through a culture of collaboration. But in real terms, how do you: Integrate activities across diverse teams and services? Make objective decisions with system-wide visibility? Use feedback loops to enable learning and improvement? With technology insights and real-world examples, in his general session at @DevOpsSummit, at 21st Cloud Expo, Andi Mann, Chief Technology Advocate at Splunk, explored how leading organizations use data-driven DevOps to close th...
As many know, the first generation of Cloud Management Platform (CMP) solutions were designed for managing virtual infrastructure (IaaS) and traditional applications. But that's no longer enough to satisfy evolving and complex business requirements. In his session at 21st Cloud Expo, Scott Davis, Embotics CTO, explored how next-generation CMPs ensure organizations can manage cloud-native and microservice-based application architectures, while also facilitating agile DevOps methodology. He expla...
To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
"Digital transformation - what we knew about it in the past has been redefined. Automation is going to play such a huge role in that because the culture, the technology, and the business operations are being shifted now," stated Brian Boeggeman, VP of Alliances & Partnerships at Ayehu, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
You know you need the cloud, but you're hesitant to simply dump everything at Amazon since you know that not all workloads are suitable for cloud. You know that you want the kind of ease of use and scalability that you get with public cloud, but your applications are architected in a way that makes the public cloud a non-starter. You're looking at private cloud solutions based on hyperconverged infrastructure, but you're concerned with the limits inherent in those technologies. What do you do?
"I focus on what we are calling CAST Highlight, which is our SaaS application portfolio analysis tool. It is an extremely lightweight tool that can integrate with pretty much any build process right now," explained Andrew Siegmund, Application Migration Specialist for CAST, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Synametrics Technologies will exhibit at SYS-CON's 22nd International Cloud Expo®, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Synametrics Technologies is a privately held company based in Plainsboro, New Jersey that has been providing solutions for the developer community since 1997. Based on the success of its initial product offerings such as WinSQL, Xeams, SynaMan and Syncrify, Synametrics continues to create and hone inn...
"We started a Master of Science in business analytics - that's the hot topic. We serve the business community around San Francisco so we educate the working professionals and this is where they all want to be," explained Judy Lee, Associate Professor and Department Chair at Golden Gate University, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"Evatronix provides design services to companies that need to integrate the IoT technology in their products but they don't necessarily have the expertise, knowledge and design team to do so," explained Adam Morawiec, VP of Business Development at Evatronix, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
The 22nd International Cloud Expo | 1st DXWorld Expo has announced that its Call for Papers is open. Cloud Expo | DXWorld Expo, to be held June 5-7, 2018, at the Javits Center in New York, NY, brings together Cloud Computing, Digital Transformation, Big Data, Internet of Things, DevOps, Machine Learning and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding busin...
There is a huge demand for responsive, real-time mobile and web experiences, but current architectural patterns do not easily accommodate applications that respond to events in real time. Common solutions using message queues or HTTP long-polling quickly lead to resiliency, scalability and development velocity challenges. In his session at 21st Cloud Expo, Ryland Degnan, a Senior Software Engineer on the Netflix Edge Platform team, will discuss how by leveraging a reactive stream-based protocol,...
In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, led attendees through the exciting evolution of the cloud. He looked at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering m...
The dynamic nature of the cloud means that change is a constant when it comes to modern cloud-based infrastructure. Delivering modern applications to end users, therefore, is a constantly shifting challenge. Delivery automation helps IT Ops teams ensure that apps are providing an optimal end user experience over hybrid-cloud and multi-cloud environments, no matter what the current state of the infrastructure is. To employ a delivery automation strategy that reflects your business rules, making r...