Welcome!

Machine Learning Authors: Jason Bloomberg, Dan Blacharski, Darren Anstee, William Schmarzo, Gopala Krishna Behara

Related Topics: SDN Journal, Java IoT, Microsoft Cloud, Containers Expo Blog, @CloudExpo, @DXWorldExpo

SDN Journal: Blog Feed Post

Scaling Stateful Network Devices

One of the premises of SDN and cloud scalability is that it's easy to simply replicate services

One of the premises of SDN and cloud scalability is that it's easy to simply replicate services - whether they be application or network focused - and distribute traffic across them to scale infinitely.

In theory, this is absolutely the case. In theory, one can continue to add capacity to any layer of the data center and simply distribute requests across the layer to scale out as necessary.

Where reality puts a big old roadblock in the way is when services are stateful. This is the case with many applications - much to the chagrin of cloud and REST purists, by the way - and it is also true with a significant number of network devices. Unfortunately, it is often these devices that proponents of network virtualization target without offering a clear path to addressing the challenges inherent in scaling stateful network devices.

SDN's claims to supporting load balancing, at least at layer 4, are almost certainly based on traditional, dumb layer 4 load balancing. We use the term "dumb" to simply mean that it doesn't care about the payload or the application or anything else other than its destination port and service and does not participate in the flow. In most layer 4 load balancing scenarios for which this is the case, the only time the load balancer examines the traffic is when processing a new connection. The load balancer may buffer enough packets to determine some basic networking details - source and destination IP and TCP ports - and then it establishes a connection between the client and the server. From this point on, generally speaking, the load balancer assumes the role of a simple forwarder. Subsequent packets with the same pattern are simply forwarded on to the destination.

If you think about it, this is so close to the behavior described by an SDN-enabled network as to be virtually the same. In an SDN-enabled network, a new flow (session if you will, in the load balancing vernacular) would be directed to the SDN controller for processing. The SDN controller would determine its destination and inform the appropriate network components of that decision. Subsequent packets with the same pattern would be forwarded on to the destination according to the information in the FIB (Forwarding Information Base). As the load balancing service was scaled out, inevitably packets would be distributed to components lacking an entry in the FIB. Said components would query the controller, which would simply return the appropriate entry to the device.

In such a way, simple layer 4 load balancing can be achieved via SDN*.

However, the behavior of the layer 4 load balancing service described is stateless. It does not actively manage the flow. Aside from the initial inspection and routing decision, the load balancing service is actually just a bump in the wire, forwarding packets much in the same manner as any other switch in the network.

But what happens when the load balancing service is actively participating in the flow, i.e. it is stateful.

Scaling Stateful Devices

Stateful devices are those that actively manage a flow. That is, they may inspect, manipulate, or otherwise interact with flows in real-time. These devices are often used for security - both ingress and egress - as well as acceleration and optimization of application exchanges. They are also use for content transformation purposes, such as XML or SOA gateways, API management, and other application-focused scenarios. The most common use of stateful devices is persistent load balancing, aka sticky sessions, aka server affinity. Persistent load balancing requires the load balancing service (or device) maintain a mapping of user to application instance (or server, in traditional, non-virtualized environments). This mapping is unique to the device, and without it a wide variety of applications break when scaled - VDI being the most recent example of an application relying on persistence of sessions .

In all these cases, however, one thing is true: the device providing the service is an active participant. The device maintains service-specific information regarding a variety of variables including the user, the device, the traffic, the application, the data. The entire context of the session is often maintained by one or more devices along the traffic chain.

What that means is that, like stateful, shared-nothing applications, it matters to which device a specific request is directed. While certainly the same model used at layer 4 and below in which a central controller (or really bank of controllers) maintains this information and doles it on on-demand, the result is that depending on the distribution algorithm used, every stateful device would end up with the same flows installed. In the interim, the network is frantically applying optimization and acceleration policies to traffic that may be offset by the latency introduced by the need to query the controller for session state information, resulting in a net loss of performance experienced by the end-user.

And we're not even considering the impact of secured traffic on such a model, where any device needing to make decisions on such traffic must have access to the certificates and keys used to encrypt the traffic in order to decrypt, examine, and usually re-encrypt the traffic. Stateful network devices - application delivery controllers, intrusion prevention and detection systems, secure gateways, etc... - are often required to manage secured content, which means distributing and managing certificates and keys across what may be an ever-expanding set of network devices.

The reality is that stateful network devices are a necessary and integral component of not just networks but applications today. While modern network architectures like SDN bring much needed improvements to provisioning and management of large scale networks, their scaling models are based on the premise of stateless, relatively simple devices not actively participating in flows. For those devices that rely upon deep participation in the flow, this model introduces a variety of challenges that may not find a solution that fits well with SDN without compromising on performance outside new protocols capable of carrying that state persistently throughout the lifetime of a session.

* This does not address the issue of resources required to maintain said forwarding tables in a given device, which given current capacity of commoditized switches supported for such a role seems unlikely to be realistically achieved.

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
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...
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...
Modern software design has fundamentally changed how we manage applications, causing many to turn to containers as the new virtual machine for resource management. As container adoption grows beyond stateless applications to stateful workloads, the need for persistent storage is foundational - something customers routinely cite as a top pain point. In his session at @DevOpsSummit at 21st Cloud Expo, Bill Borsari, Head of Systems Engineering at Datera, explored how organizations can reap the bene...
Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications. Kubernetes was originally built by Google, leveraging years of experience with managing container workloads, and is now a Cloud Native Compute Foundation (CNCF) project. Kubernetes has been widely adopted by the community, supported on all major public and private cloud providers, and is gaining rapid adoption in enterprises. However, Kubernetes may seem intimidating and complex ...
In a recent survey, Sumo Logic surveyed 1,500 customers who employ cloud services such as Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP). According to the survey, a quarter of the respondents have already deployed Docker containers and nearly as many (23 percent) are employing the AWS Lambda serverless computing framework. It’s clear: serverless is here to stay. The adoption does come with some needed changes, within both application development and operations. Tha...
In his session at 21st Cloud Expo, Michael Burley, a Senior Business Development Executive in IT Services at NetApp, described how NetApp designed a three-year program of work to migrate 25PB of a major telco's enterprise data to a new STaaS platform, and then secured a long-term contract to manage and operate the platform. This significant program blended the best of NetApp’s solutions and services capabilities to enable this telco’s successful adoption of private cloud storage and launching ...
The past few years have brought a sea change in the way applications are architected, developed, and consumed—increasing both the complexity of testing and the business impact of software failures. How can software testing professionals keep pace with modern application delivery, given the trends that impact both architectures (cloud, microservices, and APIs) and processes (DevOps, agile, and continuous delivery)? This is where continuous testing comes in. D
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...
Smart cities have the potential to change our lives at so many levels for citizens: less pollution, reduced parking obstacles, better health, education and more energy savings. Real-time data streaming and the Internet of Things (IoT) possess the power to turn this vision into a reality. However, most organizations today are building their data infrastructure to focus solely on addressing immediate business needs vs. a platform capable of quickly adapting emerging technologies to address future ...
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 in...
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.
Nordstrom is transforming the way that they do business and the cloud is the key to enabling speed and hyper personalized customer experiences. In his session at 21st Cloud Expo, Ken Schow, VP of Engineering at Nordstrom, discussed some of the key learnings and common pitfalls of large enterprises moving to the cloud. This includes strategies around choosing a cloud provider(s), architecture, and lessons learned. In addition, he covered some of the best practices for structured team migration an...
With tough new regulations coming to Europe on data privacy in May 2018, Calligo will explain why in reality the effect is global and transforms how you consider critical data. EU GDPR fundamentally rewrites the rules for cloud, Big Data and IoT. In his session at 21st Cloud Expo, Adam Ryan, Vice President and General Manager EMEA at Calligo, examined the regulations and provided insight on how it affects technology, challenges the established rules and will usher in new levels of diligence arou...
Most technology leaders, contemporary and from the hardware era, are reshaping their businesses to do software. They hope to capture value from emerging technologies such as IoT, SDN, and AI. Ultimately, irrespective of the vertical, it is about deriving value from independent software applications participating in an ecosystem as one comprehensive solution. In his session at @ThingsExpo, Kausik Sridhar, founder and CTO of Pulzze Systems, discussed how given the magnitude of today's application ...
The “Digital Era” is forcing us to engage with new methods to build, operate and maintain applications. This transformation also implies an evolution to more and more intelligent applications to better engage with the customers, while creating significant market differentiators. In both cases, the cloud has become a key enabler to embrace this digital revolution. So, moving to the cloud is no longer the question; the new questions are HOW and WHEN. To make this equation even more complex, most ...
As you move to the cloud, your network should be efficient, secure, and easy to manage. An enterprise adopting a hybrid or public cloud needs systems and tools that provide: Agility: ability to deliver applications and services faster, even in complex hybrid environments Easier manageability: enable reliable connectivity with complete oversight as the data center network evolves Greater efficiency: eliminate wasted effort while reducing errors and optimize asset utilization Security: imple...
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 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...
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...
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...