Welcome!

Cloud Security Authors: Christopher Harrold, Craig Lowell, Elizabeth White, Richard Hale, Greg Schulz

Related Topics: SDN Journal, Java IoT, Linux Containers, Containers Expo Blog, @CloudExpo, Cloud Security

SDN Journal: Blog Feed Post

SDN Prerequisite: Stateful vs Stateless

Things you need to know before diving into SDN...

We've talked before about the bifurcation of the network, which is driven as much by the evolution of network services from "nice to have" to "critical" as it is by emerging architectures. The demarcation line in the network stack has traditionally been - and remains - between layers 3 and 4 in the OSI model. The reason for this is that there is a transition as you move from layer 3 to layer 4 from stateless networking to stateful networking.

bifurcated-network-stateful-statelessThis is important to emerging architectures like SDN because this characteristic determines what level of participation in the data path is required.

Stateless networking requires very little participation. It's limited to evaluating network protocol frames and headers for the purpose of determining where to forward any given packet. The information extracted from the packet is not saved; it is not compared to previous packets.This is why it's stateless, because no information regarding the state of the communication is retained. It is evaluated and the packet is forwarded out the appropriate port based on what's in the FIB (Forwarding Information Base) or what's more commonly referred to as the "forwarding table."

Stateful networking, which begins at layer 4, retains certain information extracting from frames and packets and, as you move up the stack, from the application layer. It does this because protocols like TCP are connection-oriented and try to maintain guaranteed delivery. This is achieved through the use of sequence numbers in the TCP headers that, when out of order or lost cause the network to retransmit the packets.

There is state associated with TCP, i.e. "I have received packet 1 and am waiting for packet 2 in this connection." This is readily seen in the use of ACKnowledgment packets associated with TCP. There is a pre-designated flow associated with TCP that depends on the state of the end-points involved in the connection.

tcp-conversation-2

When a networking service operating at layer 4 or higher is inserted into this communication flow, it must also maintain the connection state. This is particularly true of staple stateful services such as security and load balancing, which rely on state to provide stateful failover services (i.e., without simply dropping connections) or to detect attacks based on state, such as SYN floods.

The higher a network service operates in the network stack, the more participation is required. For example, application routing based on HTTP headers (the URI, the hostname, cookie values, etc... ) rely on the ability of an intermediate network device maintaining state as well as extracting data from within the payload of a message (which is not the same as a packet). A message might actually require 2 or 3 or more packets, as data transferred by modern web applications is often larger than the network MTU of 1500 bytes. This means the intermediate device operating at the application layer must be stateful, as it must act as the end point for the connection in order gather all the packets that make up a message before it can extract the data and then execute its policies. This is why we also emphasize that layer 2-3 is "fixed" and layer 4-7 is "variable."

Networking protocols at layer 2-3 are governed by standards that clearly define the layout of Ethernet frames and IP packets. Devices operating at those layers have highly optimized algorithms for extracting the information needed from frames and packet headers in order to determine how to forward the packet. TCP affords the same luxury at layer 4, but as networking moves up the stack the exactly location of information necessary to make a forwarding decision become highly variable.

Even with a clearly defined protocol like HTTP, there is a wide variation in where certain data might be in the header. This is because not all headers are required and unlike Ethernet and IP and even TCP, where options may not be specified, there is still room reserved for those values. HTTP does not require that space be reserved for optional headers. They are simply left out, which can dramatically change the location (and thus the method of extraction by the intermediate device) of the data necessary to formulate a forwarding decision.

Say you had a form to fill out and, depending on the answer to question 2 you might go on to question 3 or skip to question 8. If that form were layer 2 or 3, each question would be clearly numbered. Skipping to question 8 would be quick and easy. But if that form were layer 7, the questions are not labeled, and to get to question 8 you have to count each of the questions manually. That's the difference between "fixed" and "variable". It's why compute resource requirements are more important to layer 7 than they are to layer 2 or 3.

Why this matters to SDN

This matters a great deal to SDN architectures because of how it impacts the control-data plane separation architecture. Stateless networking is perfectly suited to an architecture that places responsibility for making forwarding decisions on a centralized controller because the frequency with which those decisions must be made is relatively low. Conversely, stateful networking requires more participation and more frequent decisions as well as requiring the maintenance of state for each and every connection. This has serious implications for the controller in such a model, as it forces issues of controller scalability and resource requirements into the equation as the controller more actively participates (and stores more information) with stateful networking than it does with stateless networking.

This is not to say that SDN architecture is incompatible with higher order network services. It just means that the SDN solution you choose for stateless networking will almost certain not be the same SDN solution you choose for stateful networking. That means it's important to investigate solutions that address both of your "networks" with an eye toward integration and interoperability.

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.

@ThingsExpo Stories
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
WebRTC is bringing significant change to the communications landscape that will bridge the worlds of web and telephony, making the Internet the new standard for communications. Cloud9 took the road less traveled and used WebRTC to create a downloadable enterprise-grade communications platform that is changing the communication dynamic in the financial sector. In his session at @ThingsExpo, Leo Papadopoulos, CTO of Cloud9, discussed the importance of WebRTC and how it enables companies to focus...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
ReadyTalk has expanded the capabilities of the FoxDen collaboration platform announced late last year to include FoxDen Connect, an in-room video collaboration experience that launches with a single touch. With FoxDen Connect, users can now not only engage in HD video conferencing between iOS and Android mobile devices or Chrome browsers, but also set up in-person meeting rooms for video interactions. A host’s mobile device automatically recognizes the presence of a meeting room via beacon tech...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
It’s 2016: buildings are smart, connected and the IoT is fundamentally altering how control and operating systems work and speak to each other. Platforms across the enterprise are networked via inexpensive sensors to collect massive amounts of data for analytics, information management, and insights that can be used to continuously improve operations. In his session at @ThingsExpo, Brian Chemel, Co-Founder and CTO of Digital Lumens, will explore: The benefits sensor-networked systems bring to ...
On Dice.com, the number of job postings asking for skill in Amazon Web Services increased 76 percent between June 2015 and June 2016. Salesforce.com saw its own skill mentions increase 37 percent, while DevOps and Cloud rose 35 percent and 28 percent, respectively. Even as they expand their presence in the cloud, companies are also looking for tech professionals who can manage projects, crunch data, and figure out how to make systems run more autonomously. Mentions of ‘data science’ as a skill ...
Manufacturers are embracing the Industrial Internet the same way consumers are leveraging Fitbits – to improve overall health and wellness. Both can provide consistent measurement, visibility, and suggest performance improvements customized to help reach goals. Fitbit users can view real-time data and make adjustments to increase their activity. In his session at @ThingsExpo, Mark Bernardo Professional Services Leader, Americas, at GE Digital, discussed how leveraging the Industrial Internet a...
Amazon has gradually rolled out parts of its IoT offerings in the last year, but these are just the tip of the iceberg. In addition to optimizing their back-end AWS offerings, Amazon is laying the ground work to be a major force in IoT – especially in the connected home and office. Amazon is extending its reach by building on its dominant Cloud IoT platform, its Dash Button strategy, recently announced Replenishment Services, the Echo/Alexa voice recognition control platform, the 6-7 strategic...
In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.
There will be new vendors providing applications, middleware, and connected devices to support the thriving IoT ecosystem. This essentially means that electronic device manufacturers will also be in the software business. Many will be new to building embedded software or robust software. This creates an increased importance on software quality, particularly within the Industrial Internet of Things where business-critical applications are becoming dependent on products controlled by software. Qua...
Big Data, cloud, analytics, contextual information, wearable tech, sensors, mobility, and WebRTC: together, these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at @ThingsExpo, Erik Perotti, Senior Manager of New Ventures on Plantronics’ Innovation team, provided an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it ...
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices 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 business opportuni...
IoT is rapidly changing the way enterprises are using data to improve business decision-making. In order to derive business value, organizations must unlock insights from the data gathered and then act on these. In their session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, and Peter Shashkin, Head of Development Department at EastBanc Technologies, discussed how one organization leveraged IoT, cloud technology and data analysis to improve customer experiences and effi...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
SYS-CON Events announced today that MangoApps will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides modern company intranets and team collaboration software, allowing workers to stay connected and productive from anywhere in the world and from any device.