Welcome!

Related Topics: SDN Journal, Java IoT, Microservices Expo, Containers Expo Blog, @CloudExpo, @BigDataExpo

SDN Journal: Article

Beyond SDN: Creating Focused and Useable Solutions

The real customers and end users want practical and usable solutions, not definitions

Software Defined Networking (SDN) has become a famous paradigm and also the bandwagon in the networking industry today. SDN is primarily considered to be a methodology or approach to solving some of the wider-known problems in the enterprise and service provider networking space. It's also a tool to create some exciting new features today. The term "Software Defined Networking" provides a green-field opportunity for vendors to define, promote and customize it in their own way. End users don't care so much about the definition; they are more concerned about its contribution in optimizing and solving real problems.

The initial protocol that is considered to be a precursor to SDN is "OpenFlow." Open Networking Foundation (ONF) defines SDN as a new approach to networking, whereby, network control is decoupled from the data-forwarding function and is directly programmable. OpenFlow allows the traditional layer 2 switches to examine headers in the packet/frame and make forwarding decisions. OpenFlow-supported switches examine the packet headers through the transport layers and can match more than 13 fields that span across layer 2 to layer 4.

How Exactly Is It Going to Be Useful?
There are some interesting use cases defined by various vendors that utilize the IP and TCP header look-up to make forwarding decisions. Even though these use cases are not fully established, they may be useful to perform traffic redirection and traffic engineering by merely using switches. Some practical uses of traffic engineering would be to isolate the malicious traffic at the switch level for further analysis and containment. Another example would be the ability to divert traffic through multiple ISP connections based on applications and specific computers (users). Many vendors are focusing on getting these use cases established by creating controllers and switches. Controllers push the rules onto the switches. Switches perform the packet processing, rule lookup and makes forwarding decisions. OpenFlow controllers and switches are considered to be the two main pieces of SDN by many vendors. Other software is currently being developed and promoted under the SDN umbrella such as Orchestration/Automation software.

Why Do We Need Orchestration/Automation Software?
Orchestration/automation software is primarily considered to be a component that sits on top of the controller and uses the controller's northbound APIs to execute sets of tasks in sequence based on events and monitoring. Usually these tasks are performed by scripts that run on either a time-bound or situation-bound way manually set in place by system administrators. As an example, scripts could be a weakened configuration script, a flash crowd-specific network, server configuration script, etc. It provides the ability to perform scenario-specific, time-specific, or business-policy-specific infrastructure setup and configuration. Orchestration software brings these scripts under a single umbrella of SDN and masks the error-prone programming needs from the system administrators to provide a user-friendly and easy-to-configure, easy-to-monitor graphical user interface.

One of the most important uses of Orchestration/Automation software is in cloud computing. The cloud is in essence a data center that runs services on top of physical servers directly or on virtual machines that share a single physical server and provides a user-friendly interface to manage the services, the virtual machines (VM), the servers and the whole infrastructure. The main idea behind consolidating the VMs on a single physical server is to maximize the utilization of the hardware resources that are invested and minimize the operational expenses (OPEX) such as energy costs by running the fewest possible physical servers for a given load. As loads increase, more VMs require enabling to balance the load and provide optimum service. Hardware virtualization software (hypervisors) makes the process of preserving a running operating system as a snapshot or image easy and automatic. When a snapshot is created as a virtual machine, it's important to get the underlying networking also reconfigured automatically. This is where OpenFlow comes into play to enable network virtualization.

Here's how it works. When the VM is booted up and sends the first Ethernet frame outbound, the switch captures it and sends layer 2 and layer 4 header information to the controller and checks where to forward the packets. Controller creates the dynamic "vlan-like" port grouping based on predefined policies using MAC addresses or IP addresses. Without any administrative intervention, the newly created VM is already part of the existing network and is part of the pre-configured load balancer server pool. This practical and exciting approach makes good use of the SDN. The automation is generally done through the hypervisor or management software that runs above the hypervisor. While this automation seems magical, there are some important points to consider.

What's the Catch?
Like expert magicians, SDN vendors misdirect the users about the features and opportunities of control and data plane separation while not revealing some important facts. When lots of promotional and inaccurate information about SDN prevails in the market, we should also learn to look behind the curtains to fully understand the price that is paid for the new features. When we look closely, the price of enabling OpenFlow is obvious; it's performance. Traditional switches are meant to look up the layer 2 fixed length headers. Conversely, OpenFlow switches look up variable length headers such as IP and TCP. While the effort to examine length-delimited lookup and parsing is obvious, there are some good readings that detail the performance penalties of handing variable length headers compared to fixed-length headers.

Although OpenFlow switches open up an exciting new approach and bring a huge momentum to the networking industry, the illusion of them replacing all the layer 2 switches will not hold up very well when you actually put them to test and compare the results. OpenFlow should complement the existing infrastructure and should not attempt to replace traditional switches since OpenFlow switches try to solve a different set of problems. Pricing what we pay to automatically detect the newly created VM or newly created application session is actually impacting the packet/frame forwarding performance immensely. While OpenFlow is still useful as traffic engineering and as a flow management tool, it should not be considered a replacement for a layer 2 switch. It's not just based on the OpenFlow protocol maturity at this point; it's based on its design itself.

Hidden Gem
One of the important aspects of the SDN that does not get much traction on the specifics is northbound APIs. While ‘application-oriented' and ‘application-defined' software and networking product promotions have been swamping the industry, this is really about engineering application traffic based on TCP port numbers. But correctly implemented northbound APIs can bridge the gap between the application and networking worlds. Industry brilliance should be applied to solve the real age-old problem: TCP. Applications utilize TCP. Application developers consider networking as a one big pipe of unlimited bandwidth and speed of light connectivity. Applications have limited visibility into the underlying networking or server infrastructure. In the SDN world, controller vendors are pondering and developing northbound APIs. Most controller developers are considering these APIs only as a CLI replacement. They are also viewing it as a southbound interface to another network automation or management software.

Let the Application Be the Controller
Think of the gravity hydro-dams. When counties around the state are requesting more water for irrigation, what happens if the dam's controller decides to honor every request for the needed amount? Should it open the water-gate to its fullest to serve all the required quantity without considering how much the distribution pipes can handle? Although most people will not think of doing this, this is exactly what is happening in the software world today.

When the application receives the incoming requests, it assumes the network has unlimited capacity and light-speed connectivity to the one making the request. Applications start creating packets by spending CPU, memory and disk resources. Later, the network optimization or QoS device finds out that the links are overused and decides to drop the packets to inform the applications to slow down. All of the resources consumed were not only going to waste, it also created more congestion on the network. Instead of using ancient smoke-signaling approaches like packet drops to inform the applications about the network congestion, SDN vendors should build more robust northbound APIs to provide more network visibility to the applications. It will be a paradigm shift in the way applications are developed. It will address the problem at its source. The promise relies on the simplicity and standardization of the northbound APIs.

Although the northbound APIs are not well defined and left for vendors to implement their own sets of rules, the power to make the SDN succeed lies in the northbound APIs. It is the real disruption in the industry not the data and control plane separation.

Northbound APIs for Policy Plane
As the controller's northbound API is to the underlying infrastructure, the needs for northbound APIs for the policy plane are also growing. Policies change all the time to align with business goals as they drive the infrastructure both directly and indirectly. When the policy plane also exposes the APIs for applications to consume the priorities and service level agreements (SLA), the same occurs between the forwarding plane and control plane today on the networking side.

Northbound APIs should allow the application to query the system, network, and server infrastructure to optimize the network globally. It should also be able to interact with the policy layer to get the priorities and SLA before committing to any resources. This will exceed the end user's investment on applications and networking infrastructure while avoiding shifting problems between each other and truly begin to collaborate and complement one another.

The real customers and end users want practical and usable solutions, not definitions. We should think beyond defining the jargon and start creating focused and useable solutions.

References

  1. http://www.cs.cmu.edu/~srini/15-744/F02/readings/McK97.html#3needswitch
  2. https://www.opennetworking.org/about/onf-overview

More Stories By Karthikeyan Subramaniam

Karthikeyan Subramaniam serves as the Chief Software Architect and Architect of the Company’s Software Defined Networking Platform. He led the development of the company’s SDN and Cloud Computing Platform work for Verizon, alongside Hewlett Packard, Intel Corp, the industry leading SDN platform unveiled at the Open Networking Summit, the world’s largest SDN summit. He has created and developed the Company’s platforms in Software Defined Networking, and Interoperability. He was at Intel Technology India, in Intel Server Systems and Intelligent Platform Management. He was at Cisco Offshore Development Center in Cisco’s Enterprises Management Business Unit (EMBU) in Cisco’s Voice Systems, Voice Gateways and Gatekeepers.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Latest Stories
"We are a monitoring company. We work with Salesforce, BBC, and quite a few other big logos. We basically provide monitoring for them, structure for their cloud services and we fit into the DevOps world" explained David Gildeh, Co-founder and CEO of Outlyer, in this SYS-CON.tv interview at DevOps Summit at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
"Loom is applying artificial intelligence and machine learning into the entire log analysis process, from start to finish and at the end you will get a human touch,” explained Sabo Taylor Diab, Vice President, Marketing at Loom Systems, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
After more than five years of DevOps, definitions are evolving, boundaries are expanding, ‘unicorns’ are no longer rare, enterprises are on board, and pundits are moving on. Can we now look at an evolution of DevOps? Should we? Is the foundation of DevOps ‘done’, or is there still too much left to do? What is mature, and what is still missing? What does the next 5 years of DevOps look like? In this Power Panel at DevOps Summit, moderated by DevOps Summit Conference Chair Andi Mann, panelists loo...
"Tintri focuses on the Ops side of the DevOps, which basically is pushing more and more of the accessibility of the infrastructure to the developers and trying to get behind the scenes," explained Dhiraj Sehgal of Tintri in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
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.
@DevOpsSummit at Cloud Expo taking place Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center, Santa Clara, CA, is co-located with the 21st International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is ...
In the world of DevOps there are ‘known good practices’ – aka ‘patterns’ – and ‘known bad practices’ – aka ‘anti-patterns.' Many of these patterns and anti-patterns have been developed from real world experience, especially by the early adopters of DevOps theory; but many are more feasible in theory than in practice, especially for more recent entrants to the DevOps scene. In this power panel at @DevOpsSummit at 18th Cloud Expo, moderated by DevOps Conference Chair Andi Mann, panelists discussed...
A look across the tech landscape at the disruptive technologies that are increasing in prominence and speculate as to which will be most impactful for communications – namely, AI and Cloud Computing. In his session at 20th Cloud Expo, Curtis Peterson, VP of Operations at RingCentral, highlighted the current challenges of these transformative technologies and shared strategies for preparing your organization for these changes. This “view from the top” outlined the latest trends and developments i...
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
"We focus on composable infrastructure. Composable infrastructure has been named by companies like Gartner as the evolution of the IT infrastructure where everything is now driven by software," explained Bruno Andrade, CEO and Founder of HTBase, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
Hardware virtualization and cloud computing allowed us to increase resource utilization and increase our flexibility to respond to business demand. Docker Containers are the next quantum leap - Are they?! Databases always represented an additional set of challenges unique to running workloads requiring a maximum of I/O, network, CPU resources combined with data locality.
For organizations that have amassed large sums of software complexity, taking a microservices approach is the first step toward DevOps and continuous improvement / development. Integrating system-level analysis with microservices makes it easier to change and add functionality to applications at any time without the increase of risk. Before you start big transformation projects or a cloud migration, make sure these changes won’t take down your entire organization.
Cloud promises the agility required by today’s digital businesses. As organizations adopt cloud based infrastructures and services, their IT resources become increasingly dynamic and hybrid in nature. Managing these require modern IT operations and tools. In his session at 20th Cloud Expo, Raj Sundaram, Senior Principal Product Manager at CA Technologies, will discuss how to modernize your IT operations in order to proactively manage your hybrid cloud and IT environments. He will be sharing bes...
Artificial intelligence, machine learning, neural networks. We’re in the midst of a wave of excitement around AI such as hasn’t been seen for a few decades. But those previous periods of inflated expectations led to troughs of disappointment. Will this time be different? Most likely. Applications of AI such as predictive analytics are already decreasing costs and improving reliability of industrial machinery. Furthermore, the funding and research going into AI now comes from a wide range of com...