ONOS: The Game Changing SDN Controller?


ONOS (Open Network Operating System) is the first Open SDN Controller with focus on Service Provider Use Cases and their challenges of Scalability, High Availability & Performance. The support of Users and growing ecosystem, along with promising performance results make it a strong contender among SDN Controllers.

Software Defined Networking (SDN) has seen unprecedented hype and industry activity in the last three years.

“SDN is the next big thing in networking in decades, perhaps the next big thing after networking itself”.

Dan Pitt, ONF Executive Director

Indeed SDN brings a ray of hope for stagnating Telecom industry that might not have a sustainable business model with status quo in the future. As a result, several approaches to SDN have emerged each of its pros and cons. Among the available SDN Controllers, we have both vendor proprietary and open-source controllers. Vendor Specific controllers include VMware Nicira NSX, Cisco APIC, Alcatel-Lucent Nuage VSC, Brocade Vyatta, HP VAN and Cyan Blue Planet etc., while most notable open-source controllers are Open Daylight, Open Contrail, Big Switch Project Floodlight and Ryu etc. ONOS (Open Network Operating System) is the latest addition in the list of Open Source SDN Controller Projects. ONOS has been under development by ON.Lab (Open Networking Lab) since 2012 and was Open Sourced on Dec 5th 2014 after the support of AT&T and NTT in Nov 2014.

After having so many existing open-source controllers, one might wonder the need for another and why is it important?

To answer this, we have to look at the motivation behind open source projects and analyze various projects to see how they can deliver on the original SDN objectives of lower costs (both CAPEX & OPEX), faster TTM, Innovation, separation of control and forwarding and avoidance of vendor lock-in.

Open-source projects bring benefits such as Interoperability, Flexibility & Freedom from vendor lock-in, Customizability, reduced Costs and support from a large Community. There are three types of Open Source Ecosystems: Vendor Dominated, Loosely Aligned and Foundation Managed. The most effective and impactful projects tend to be Foundation Managed, e.g. OpenStack & Apache. The reason being a strong and independent community that is led by clear customer requirements, value proposition and transparency in rules of engagement among the members.

Majority of the existing SDN open-source initiatives are vendor dominated with inherent associated risks which could diminish the value of open-source, like vendor lock-in and business-model favoring the dominating vendor. In other words, such projects could be seen quite close to vendor proprietary solutions with the exception of added customization and interoperability.

One exception is OpenDaylight, which is a Linux Foundation project, supported by the largest community of vendors and has released its second code base Helium in March 2015. However, there has been skepticism over its intentions fueled by the fear that it was dominated by heavyweights like Cisco and IBM. ONF’s Dan Pitt also expressed his concerns that OpenDaylight seemed to have slowed down the SDN market innovation and it did not involve any users which was critical to understand and meet real user needs. ONF has also been critical of Cisco’s proposed OPFlex protocol which is now expected to emerge in OpenDaylight’s upcoming “Lithium” release.

In this context, ONOS has emerged as the first Open-Source SDN project focusing exclusively on service provider use cases and led by users including operators like AT&T, NTT, SK Telecom and ONF which has the support of software-oriented companies such as Google, Facebook, Yahoo, Verizon, and Microsoft. ONOS promised to address the challenges of Scalability, High Availability & Performance, all of which are critical for Carrier-Grade Networks.

“Software-defined networking can radically reshape the wide area network, the introduction of ONOS provides another open source SDN option designed for service provider networks with the potential to deliver the performance, scale, availability and core features that we value.”

John Donovan, SEVP, AT&T Technology & Operations.

While OpenDaylight has tried to accommodate several protocols in its southbound API layer, ONOS is focusing primarily on OpenFlow for new deployments and Netconf for legacy equipment. It also has Distributed (Clustered) Core which to provide scale-out and solve the problem of Open Flow controller scalability. It has a three month release cycle (more aggressive than ODL), the code for its second release, Blackbird, can be downloaded here.

ONOS Distributed Architecture

Given the support of large operators, vendors are rapidly joining the ecosystem and current list includes: Ericsson, Ciena, Cisco, Huawei, Intel, NEC and Fujitsu. Among them, Huawei has announced full support of ONOS in their SDN solution, while Ericsson terms ONOS as the cure for performance anxiety in SDN. Recently, ONOS has released performance metrics for its Blackbird release.

The numbers related to ONOS Blackbird performance metrics are impressive and promising.

In addition to performance, ONOS has several Service Provider Use Cases including Segment Routing, NFaaS, Multi-layer SDN and SDN-IP among others. It provides a vision of future network where POP and CO’s will be built like Data Centers and Core and Metro Packet Optical networks will be built on low cost hardware with separation of control and forwarding.

ONOS Service Provider Future Network


ONOS and OpenDaylight are the two most promising Open-Source SDN Controllers on the horizon but it’s still early days for both as yet. While ODL is arguably more mature and have a larger ecosystem (even though recently Juniper and VMWare reduced their commitments), ONOS has the increasing support of Operators and Use Cases which are customized for Operators’ requirements. Given the pace of rapid developments in the industry, it might take some time for a clear winner to emerge. The key to long-term success of either will be the adoption of real-world deployments in large-scale service provider networks.

Starting with a vendor-dominated/proprietary solutions can be a great tactical choice to understand technology, build internal capability and deploy current and immediate SDN Use Cases. However, given that SDN is going to be strategic to service provider’s core business, any SDN ecosystem should be evaluated to ensure vendor neutrality, large and non-vendor dominated base of developers & integrators and long-term viability (industry support) of the ecosystem.

Disclaimer: This article is an analysis on current and emerging state of SDN controllers and is not meant to cover a comprehensive list of SDN solutions/providers. The aim is to list examples to provide a clearer understanding but not to favor any company/vendor. All logos used in the article belong to their respective trademark owners.


Network Cloud brings a ray of hope for stagnating Telecom industry

network plus cloud

Telecom was once seen as innovative and high growth industry, telecom companies were at the forefront of the first high-tech bubble during late 90’s and early 2000’s. Traditional telecom services of voice, messaging, video broadcast and data connectivity were profitable and operator were only competing with local rivals who were all protected by their respective regulatory frameworks. As a result, they became a bit too comfortable in their modus operandi and didn’t feel the urge to innovate further.

But, other Internet OTT (over-the-top) companies exploited the lack of innovation by telecom and kept introducing services with not only enhanced features but also global/ubiquitous reach and new business models. The result was emergence of other alternatives for multimedia applications to run over data networks and even replace the traditional telecom services. As a result, telecom operators find themselves as a mere connectivity provider which is very similar to other utilities like water and electricity.

This new role could be fine if it provided a sustainable business model but with cloud, mobility and social media, telcos are facing an explosion of data on their networks where they have to keep on investing to expand the capacity but resulting revenues are not growing in-line with the expenses. Result is reduced profitability and excessive pressure on both CAPEX and OPEX spending.

network cloud

Now the rise of Network Cloud enabled by SDN (software defined networking) and NFV (network functions virtualization) has promised to address several of the challenges that exist for Telecom Operators worldwide and a major factor as why they are less competitive than OTT players.

Both SDN and NFV have taken the telecom industry by storm in the past two years. The level of excitement, buzz and industry activity during this time is unseen in telecom history. Perhaps this is as major a paradigm shift as moving from analogue to digital or from TDM to IP.

The industry has seen a rapid development in SDN/NFV technology solutions. The incumbent vendors are busy in evolving their SDN and NFV stories while it has become a lot easier than before for new players to not only enter the market but to pose a head-on challenge to incumbents in major network build-outs as was shown by AT&T during its selection of vendors for Domain 2.0: User-Defined Network Cloud.

It’s important to understand the benefits brought by network cloud in order to analyze whether the unprecedented hype surrounding SDN and NFV is justified or not.

Reduced disparity between costs and revenues

Using COTS servers and white label switches will have a direct impact on both CAPEX and OPEX due to shared hardware resources, reduced space, power and cooling requirements etc. When we couple the reduced costs with the ability to offer more innovative services (e.g. bandwidth on demand for enterprise applications or flexible, reconfigurable, virtualized data-centric network), the disparity between costs and revenues will decrease.

Increased flexibility, agility and resource utilization

Currently network resources are statically configured and cannot be moved when & where needed. The networks are planned and dimensioned for peak capacity which results in wasted infrastructure resources.

As with Cloud Computing, virtualizing network resources will enable dynamic allocation and hence dimensioning for average rather than peak.

Faster time to market (TTM)

Current telecom product development cycles are hardware-oriented which normally run from idea generation, development of business plan, definition of requirements, requests for proposals, evaluations/negotiations, shipment, deployment, typically complex OSS/BSS integration, acceptance testing and finally service introduction. The result is that, on average, it takes 12 – 24 months to introduce new service for telecom operators. While they are competing with OTT players who, by relying solely on software solutions and Cloud technologies, are able to bring a new service in less than 3 months. Network virtualization shall enable the same kind of TTM to that operators can respond must faster to changing market needs.

Reduced Complexity and easier inventory management

Today’s networks have enormous variety of proprietary hardware appliances which mandated operators to follow hardware obsolescence cycles to ensure ROI (return on investment). Keeping & tracking inventory & spares for all different kinds of hardware is also a major overhead in network maintenance.

By utilizing industry standard COTS (commercial off-the-shelf) servers and white label switches, the operators will be able to significantly reduce the type of hardware to be managed.