|By Lori MacVittie||
|January 30, 2013 10:00 AM EST||
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.
SYS-CON Events announced today that TMCnet has been named “Media Sponsor” of SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Technology Marketing Corporation (TMC) is the world's leading business to business and integrated marketing media company, servicing niche markets within the communications and technology industries.
Oct. 31, 2014 04:45 PM EDT Reads: 660
As cloud gives an opportunity to businesses to buy services externally - how is cloud impacting your customers? In his General Session at 15th Cloud Expo, Fabio Gori, Director of Worldwide Cloud Marketing at Cisco, will provide answers to big questions: Do you see hybrid cloud as where the world is going? What benefits does it bring? And how does Cisco connect all of these clouds? He will also tell us everything about Intercloud and Cisco investment on it.
Oct. 31, 2014 04:45 PM EDT Reads: 627
Can we look to the paradigm of cloud computing from a completely different perspective? In his General Session at 15th Cloud Expo, Gundars Kulups, Sales Director at DEAC, will discuss what we can learn from our dining habits when choosing a cloud solution. Gundars Kulups is Sales Director at DEAC, full service data center operator. An IT expert, he specializes in European countries and has worked in the IT industry since 1992. He graduated from Riga Technical University (RTU) in Latvia and com...
Oct. 31, 2014 04:45 PM EDT Reads: 526
SYS-CON Events announced today that Parasoft will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. For 27 years, Parasoft has researched and developed software solutions that help organizations deliver defect-free software efficiently. By integrating Development Testing, API/cloud/SOA/composite app testing, and service virtualization, we reduce the time, effort, and cost of delivering secur...
Oct. 31, 2014 04:30 PM EDT Reads: 933
The Internet of Things (IoT) promises to evolve the way the world does business; however, understanding how to apply it to your company can be a mystery. Most people struggle with understanding the potential business uses or tend to get caught up in the technology, resulting in solutions that fail to meet even minimum business goals. In his session at Internet of @ThingsExpo, Jesse Shiah, CEO / President / Co-Founder of AgilePoint Inc., will show what is needed to leverage the IoT to transform...
Oct. 31, 2014 04:00 PM EDT Reads: 1,566
SYS-CON Events announced today that Utimaco will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Utimaco is a leading manufacturer of hardware based security solutions that provide the root of trust to keep cryptographic keys safe, secure critical digital infrastructures and protect high value data assets. Only Utimaco delivers a general-purpose hardware security module (HSM) as a customiz...
Oct. 31, 2014 03:00 PM EDT Reads: 1,916
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, will describe an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-devic...
Oct. 31, 2014 02:00 PM EDT Reads: 1,789
Until recently, many organizations required specialized departments to perform mapping and geospatial analysis, and they used Esri on-premise solutions for that work. In his session at 15th Cloud Expo, Dave Peters, author of the Esri Press book Building a GIS, System Architecture Design Strategies for Managers, will discuss how Esri has successfully included the cloud as a fully integrated SaaS expansion of the ArcGIS mapping platform. Organizations that have incorporated Esri cloud-based appl...
Oct. 31, 2014 01:30 PM EDT Reads: 2,121
Dyn solutions are at the core of Internet Performance. Through traffic management, message management and performance assurance, Dyn is connecting people through the Internet and ensuring information gets where it needs to go, faster and more reliably than ever before. Founded in 2001 at WPI, Dyn’s global presence services more than four million enterprise, small business and personal customers.
Oct. 31, 2014 01:00 PM EDT Reads: 1,983
Once the decision has been made to move part or all of a workload to the cloud, a methodology for selecting that workload needs to be established. How do you move to the cloud? What does the discovery, assessment and planning look like? What workloads make sense? Which cloud model makes sense for each workload? What are the considerations for how to select the right cloud model? And how does that fit in with the overall IT tranformation? In his session at 15th Cloud Expo, John Hatem, head of V...
Oct. 31, 2014 01:00 PM EDT Reads: 1,877
IBM and Tencent Cloud signed a business cooperation memorandum to collaborate on providing public cloud with Software-as-a-Service solutions for industries. Both parties agreed to focus on emerging small and medium enterprises in the smarter cities and smarter healthcare industries as well as other fields. This will enable these industries to utilize mobile, cloud computing and big data tools to transform internal processes and operations, thus achieving cloud transformation in the era of mobili...
Oct. 31, 2014 11:58 AM EDT Reads: 711
SimpleECM is the only platform to offer a powerful combination of enterprise content management (ECM) services, capture solutions, and third-party business services providing simplified integrations and workflow development for solution providers. SimpleECM is opening the market to businesses of all sizes by reinventing the delivery of ECM services. Our APIs make the development of ECM services simple with the use of familiar technologies for a frictionless integration directly into web applicat...
Oct. 31, 2014 11:00 AM EDT Reads: 1,977
European data center operator DEAC is the largest in the Baltics. The activities are orientated to provide data center services and IT outsourcing on Eurasia and America scale in order to create the primary or backup or additional data center for customer in the EU, to protect its business and, most importantly, reduce costs up to 40% within 3-5 years. DEAC is an IT outsourcing services and solutions company whose highly experienced and qualified employees offer various groups of services and...
Oct. 31, 2014 09:45 AM EDT Reads: 2,282
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at Internet of @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, will discuss how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money! Speaker Bio: ...
Oct. 31, 2014 09:00 AM EDT Reads: 2,317
Samsung VP Jacopo Lenzi, who headed the company's recent SmartThings acquisition under the auspices of Samsung's Open Innovaction Center (OIC), answered a few questions we had about the deal. This interview was in conjunction with our interview with SmartThings CEO Alex Hawkinson. IoT Journal: SmartThings was developed in an open, standards-agnostic platform, and will now be part of Samsung's Open Innovation Center. Can you elaborate on your commitment to keep the platform open? Jacopo Lenzi: S...
Oct. 31, 2014 09:00 AM EDT Reads: 3,367
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo, moderated by Ashar Baig, Research ...
Oct. 31, 2014 09:00 AM EDT Reads: 1,382
Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, will address the big issues involving these technologies and, more important, the results they will achieve. How important are public, private, and hybrid cloud to the enterprise? How does one define Big Data? And how is the IoT tying all this together?
Oct. 31, 2014 08:45 AM EDT Reads: 1,979
When an enterprise builds a hybrid IaaS cloud connecting its data center to one or more public clouds, security is often a major topic along with the other challenges involved. Security is closely intertwined with the networking choices made for the hybrid cloud. Traditional networking approaches for building a hybrid cloud try to kludge together the enterprise infrastructure with the public cloud. Consequently this approach requires risky, deep "surgery" including changes to firewalls, subnets...
Oct. 30, 2014 07:00 PM EDT Reads: 1,594
Ixia develops amazing products so its customers can connect the world. Ixia helps its customers provide an always-on user experience through fast, secure delivery of dynamic connected technologies and services. Through actionable insights that accelerate and secure application and service delivery, Ixia's customers benefit from faster time to market, optimized application performance and higher-quality deployments.
Oct. 30, 2014 07:00 PM EDT Reads: 1,887
SYS-CON Events announced today that Stratogent will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Stratogent is a custom managed services organization based in San Mateo, California. We design, implement, and support mission critical infrastructure 24x7 on premises, in datacenters and in the Cloud. Since 2005, we have acted as an extension of internal IT teams, achieving a customer reten...
Oct. 30, 2014 06:45 PM EDT Reads: 2,167