Welcome!

Containers Expo Blog Authors: Pat Romanski, Liz McMillan, Elizabeth White, Automic Blog, Derek Weeks

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

SDN Journal: Blog Feed Post

Why Network Load Balancing Is Not the Same as Application Load Balancing

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

Way back in the early days of the Internet scalability was an issue (the more things change...). One of the answers to this problem was to scale out web servers using a fairly well-proven concept called load balancing. Simply put, distribute the load across web servers to make sure everyone gets served in a timely fashion. We see this in action at stores every day when more checkout lines are added as demand increases. Well, we hope we see this in action. Too often we don't, much to our chagrin.

Anyway, the way in which early load balancing worked was simply to take a couple variables (IP address and TCP port) and then hash them together and stick them in the equivalent of a queue for a web server. Because hash values tend to distribute fairly evenly, this worked well (until we ran into the mega-proxy issue, thanks to folks like Compuserve and AOL).

This is called "network load balancing" because, well, it uses network variables to distribute load. It's quite fast, actually, because it's based on variables that are in fixed locations within a single packet: source or destination IP and TCP port. All the work is on the ingress, on the inbound side, and once the decision has been made it's a pretty simple thing to hash future packets and match it up before sending it on its way. Voila. Network load balancing.

Application load balancing, however, arose because network load balancing was all based on inbound variables. It couldn't take into consideration how loaded the chosen server was, or whether its response time was falling within acceptable business parameters, or whether it was at capacity or not. Those variables were all on the server side, and required visibility into the application, not the client.

It also couldn't account for the fact that virtual servers were popping up everywhere (multiple applications served from the same IP address and port) and forced the web server to become a load balancer itself. Which, if you think about it, was kind of crazy. If a single server couldn't scale well enough to meet demand, how is putting a single server in front of them going to help the situation?

Application load balancing (which has also been given other fancy names over the years like content switching or routing, application switching, application or page routing, etc...) is really focused on distributing load across applications intelligently. While it can use ingress variables like IP address and port, it generally doesn't because that doesn't offer the insight into which server (application, web, virtual, whatever) is going to be able to respond (has capacity) in a time frame acceptable to the business (response time) for a specific application (or piece of the application like images).

The difference between the two lies primarily in the variables used to distribute load. Network load balancing relies solely on network variables while Application load balancing relies mainly on application variables.

This change in load balancing techniques opened up all sorts of new efficiencies and scalability options because it allowed architectures to specialize - route requests for images to servers focused on serving images, requests for static content to servers focused on serving static content, etc...). It also enabled persistence (sticky sessions) which greatly accelerated the ability to scale out stateful applications in a web format.

Why Is It Important to SDN?
The reason this is important to SDN architectures is because layer 3 switches can, in fact, support network load balancing. Fairly easily, in fact. If you look at how Link Aggregation (trunking) is implemented in most switches, you'll see it's using network load balancing techniques to distribute load across trunked links and that the algorithms used are pretty much the same ones we used back in the day to load balancing servers based on network variables. The hash is pretty simple (and easily implemented) and doesn't require storing state because the hash is always based on the same variables, easily extracted from IP and TCP headers, and don't really tax the system. Forwarding tables are basically sets of inbound IP addresses, TCP ports and (switch) ports matched to outbound IP addresses, TCP ports and (switch) ports. So you can see that network load balancing wouldn't overly tax a controller (it just has to hash the right values and insert a forwarding entry) or a switch.

But it wouldn't be application centric, or be able to take into consideration things that modern load balancing services care about - like application status, connection capacity, and response times, not to mention enabling specialization of services. But in order to be application centric application load balancing must participate in the data path and have visibility into variables that aren't available in packets - they're in payloads and in the application server (instances) itself. Like the implications of being stateful versus stateless, the burden on a centralized controller would be overwhelming.

Thus while SDN principles are certainly applicable, the same architecture used to implement SDN for lower order network layer services is not going to be the same architecture used to implement SDN for higher order network layer services. When evaluating SDN solutions, it's again important to consider how any two SDN network (core and application) architectures complement one another, integrate with one another, and collaborate to enable a complete software-defined network architecture that supports the unique needs of both layer 2-3 and layer 4-7.

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
SYS-CON Events announced today that Elastifile will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Elastifile Cloud File System (ECFS) is software-defined data infrastructure designed for seamless and efficient management of dynamic workloads across heterogeneous environments. Elastifile provides the architecture needed to optimize your hybrid cloud environment, by facilitating efficient...
"We provide IoT solutions. We provide the most compatible solutions for many applications. Our solutions are industry agnostic and also protocol agnostic," explained Richard Han, Head of Sales and Marketing and Engineering at Systena America, in this SYS-CON.tv interview at @ThingsExpo, held June 6-8, 2017, at the Javits Center in New York City, NY.
SYS-CON Events announced today that GrapeUp, the leading provider of rapid product development at the speed of business, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Grape Up is a software company, specialized in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market acr...
SYS-CON Events announced today that Golden Gate University will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Since 1901, non-profit Golden Gate University (GGU) has been helping adults achieve their professional goals by providing high quality, practice-based undergraduate and graduate educational programs in law, taxation, business and related professions. Many of its courses are taug...
Recently, IoT seems emerging as a solution vehicle for data analytics on real-world scenarios from setting a room temperature setting to predicting a component failure of an aircraft. Compared with developing an application or deploying a cloud service, is an IoT solution unique? If so, how? How does a typical IoT solution architecture consist? And what are the essential components and how are they relevant to each other? How does the security play out? What are the best practices in formulating...
WebRTC is great technology to build your own communication tools. It will be even more exciting experience it with advanced devices, such as a 360 Camera, 360 microphone, and a depth sensor camera. In his session at @ThingsExpo, Masashi Ganeko, a manager at INFOCOM Corporation, will introduce two experimental projects from his team and what they learned from them. "Shotoku Tamago" uses the robot audition software HARK to track speakers in 360 video of a remote party. "Virtual Teleport" uses a...
In his session at @ThingsExpo, Arvind Radhakrishnen discussed how IoT offers new business models in banking and financial services organizations with the capability to revolutionize products, payments, channels, business processes and asset management built on strong architectural foundation. The following topics were covered: How IoT stands to impact various business parameters including customer experience, cost and risk management within BFS organizations.
SYS-CON Events announced today that Cloud Academy named "Bronze Sponsor" of 21st International Cloud Expo which will take place October 31 - November 2, 2017 at the Santa Clara Convention Center in Santa Clara, CA. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud com...
DX World EXPO, LLC., a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
SYS-CON Events announced today that DXWorldExpo has been named “Global Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Digital Transformation is the key issue driving the global enterprise IT business. Digital Transformation is most prominent among Global 2000 enterprises and government institutions.
21st International Cloud Expo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Me...
In his opening keynote at 20th Cloud Expo, Michael Maximilien, Research Scientist, Architect, and Engineer at IBM, discussed the full potential of the cloud and social data requires artificial intelligence. By mixing Cloud Foundry and the rich set of Watson services, IBM's Bluemix is the best cloud operating system for enterprises today, providing rapid development and deployment of applications that can take advantage of the rich catalog of Watson services to help drive insights from the vast t...
From 2013, NTT Communications has been providing cPaaS service, SkyWay. Its customer’s expectations for leveraging WebRTC technology are not only typical real-time communication use cases such as Web conference, remote education, but also IoT use cases such as remote camera monitoring, smart-glass, and robotic. Because of this, NTT Communications has numerous IoT business use-cases that its customers are developing on top of PaaS. WebRTC will lead IoT businesses to be more innovative and address...
In his session at @ThingsExpo, Sudarshan Krishnamurthi, a Senior Manager, Business Strategy, at Cisco Systems, discussed how IT and operational technology (OT) work together, as opposed to being in separate siloes as once was traditional. Attendees learned how to fully leverage the power of IoT in their organization by bringing the two sides together and bridging the communication gap. He also looked at what good leadership must entail in order to accomplish this, and how IT managers can be the ...
SYS-CON Events announced today that Secure Channels, a cybersecurity firm, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Secure Channels, Inc. offers several products and solutions to its many clients, helping them protect critical data from being compromised and access to computer networks from the unauthorized. The company develops comprehensive data encryption security strategie...
"DX encompasses the continuing technology revolution, and is addressing society's most important issues throughout the entire $78 trillion 21st-century global economy," said Roger Strukhoff, Conference Chair. "DX World Expo has organized these issues along 10 tracks with more than 150 of the world's top speakers coming to Istanbul to help change the world."
Recently, WebRTC has a lot of eyes from market. The use cases of WebRTC are expanding - video chat, online education, online health care etc. Not only for human-to-human communication, but also IoT use cases such as machine to human use cases can be seen recently. One of the typical use-case is remote camera monitoring. With WebRTC, people can have interoperability and flexibility for deploying monitoring service. However, the benefit of WebRTC for IoT is not only its convenience and interopera...
When shopping for a new data processing platform for IoT solutions, many development teams want to be able to test-drive options before making a choice. Yet when evaluating an IoT solution, it’s simply not feasible to do so at scale with physical devices. Building a sensor simulator is the next best choice; however, generating a realistic simulation at very high TPS with ease of configurability is a formidable challenge. When dealing with multiple application or transport protocols, you would be...
What sort of WebRTC based applications can we expect to see over the next year and beyond? One way to predict development trends is to see what sorts of applications startups are building. In his session at @ThingsExpo, Arin Sime, founder of WebRTC.ventures, discussed the current and likely future trends in WebRTC application development based on real requests for custom applications from real customers, as well as other public sources of information.
SYS-CON Events announced today that App2Cloud will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct. 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. App2Cloud is an online Platform, specializing in migrating legacy applications to any Cloud Providers (AWS, Azure, Google Cloud).