SDN Network Providers - An IT Managers view

SDN Blog post

There is a fair amount of confusion in the market place regarding SDN - Software Defined Networking - from the perspective of Enterprise business capability and a general technology understanding.
The majority of buzz we hear about surrounds hybrid networking which, in theory, is a much simpler concept. The future? In my opinion, a combination of hybrid and SDN will form the WAN services IT Managers will be procuring in the not too distant future. In fact, certain providers are using components of SDN today.

What can an SDN network provider offer?

1. SDN offers simplified central management of your WAN.

2. Agnostic termination of any circuit including Internet, MPLS, VPLS and private circuits.

3. Granular reporting, security and QoS (Quality of Service).

4. A single box to facilitate all aspects of Wide Area Networking.

What is an SDN Network?


The goal of SDN is to push forward networking management and capability innovation by removing intelligence from the device to management software which is designed to provide granular application control and security. If we were to look back and review our own past clients, analyse the decision making process, we would note the focus on proprietary technologies from the perspective of layer 3 routing and layer 2 switching. Networking migration is often painful within complex Enterprise networks as the platform requires detailed presales workflows. With this in mind, the 'perceived' best option is to stick with tried and tested single vendor solutions even though todays market place is based on widespread standardisation. 

Software Defined Networks are positioned to deploy intelligence into devices from a centralised management system with capability defined and developed by open standards. An open standard approach to networking has vast implications including lowering CAPEX cost of equipment, faster install, innovation and a much more granular control of application traffic. IT teams are familiar with features such as deep level packet inspection (provided by Firewalls) and technologies such as QoS (Quality of Service) from edge devices used to prioritise applications.

The SDN providers WAN promise would mean hardware could perform multiple functions within a single device driven by software from a centralised management console. Using an Ethernet switch as an example, the device would contain no real intelligence. Instead, the actual code to carry out feature-set instructions would be drawn from the management platform. The SDN concept would allow a single device to perform multiple in-depth features. In my opinion, the software driven approach will create capability we have not yet considered.

With all this buzz, I agree with the industry perception that nobody would want to position their company at the bleeding edge of networking technology. With this statement in mind, service providers have and will deploy tried and tested elements of SDN innovation - in other words, a productised SDN offering. Outside of standard SDN deployments, the possibilities of deploying pilots of new features in restricted areas of the network is exciting.

Open standards such as Open Flow are creating the platform for SDN innovation. In todays current networking environment, innovation is not easy due to the closed systems.

A video describes Open Flow in more detail.

Rapid patching and innovation

One of the main areas I see as being impacted by SDN is the new global threats brought about by hacking. To a certain extent, we are currently able to react quickly to new threats which appear and are specifically created to threaten our data and company IP. The software approach would allow service providers to patch and deploy solutions to threats faster. The Enterprise of the future (and largely today) requires fast deployment of patches across all devices. Open standards allow the industry to collaborate and better prepare for the threats of future hacking attempts.

Will companies such as Cisco adopt an open approach?

Everyone is welcome to an opinion here but Cisco ACI is certainly adopting an open standards approach. We would be naive to think companies such as Cisco will ultimately become completely open, without placing a certain amount of control, but the SDN ethos is certainly within the companies capability portfolio. In fact, Cisco have published their own ACI interfaces and are driving their approach into OpenStack (open source cloud software) which is maintained by a community of developers which collaborate with the end needs of users. OpenStack really defines the meaning of the world SDN but also provides control for compute and storage.

Cisco ACI described in more detail.

Cisco ACI (Application Centric Infrastructure) provides an environment for policy automation and integrates with an Enterprise businesses existing domain and appliances which fits with a cloud based model where multiple vendors exist. Ciscos marketing suggests they are bringing the full feature set into their ACI model which is good news. Their SDN offering is further enhanced with their adoption of the EVPN model which is essentially an enhancement to VXLAN. EVPN removes complexity of managing endpoints and is available on the Cisco 9000 series switches. The draft proposal for EVPN was developed in conjunction with Alcatel Lucent, Huawei and Juniper in conjunction with large service providers. Without going into too much detail, Virtual Extensible LAN (VXLAN) is used to scale large cloud computing deployments. Essentially, the protocol uses a flood and learn to discover connected devices which does not scale well in todays vast deployments. The EVPN with BGP technology overcomes the scalability limitations of a standard VXLAN deployment. In the main, the scalability is only relevant to large cloud deployments with data center virtualisation technologies.

An example of service providers offering SDN today

Network Union partner with a service provider which has been involved with SDN technology for some time now. Although their approach is relatively straight forward in terms of technology, the capability offers unique features. The mode of operation is via a MIB (Management Information Bridge) positioned behind CE (customer edge) Cisco routers providing access to the following services:

  • Ethernet Layer 3 MPLS VPN
  • Ethernet Layer 2 VPLS VPN
  • Ethernet Point to Point or Multipoint VLL (Virtual Leased Line)
  • IPSec encryption services to a centralised cloud Firewall

Overlayed across the hybrid of connectivity is a software based application which allows clients to place their own bandwidth changes, orders, upgrades, support requests and so forth. The concept is a good example of hybrid with SDN components. 

Example SDN Providers DiagConclusion

The current WAN market is very much based around the core capability of MPLS and VPLS services with a hybrid wrap to support multiple connection types such as IPSec. SDN is growing in capability but I have yet to see a fully featured SDN product which meets the overall promise of the technology. In a few years, this will no doubt change.

Alternatives to SDN? Read about NFV (Network Functions Virtualisation)

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