Interview with Patrick Kerpan of CohesiveFT

By Patrick Kerpan (Profile)
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Wednesday, November 21st 2012
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VSM: What is a Software Defined Network (SDN)?

PK: Software Defined Networking has only recently emerged from a number of different virtual and cloud fueled terms: network virtualization, cloud networking, virtual private cloud, application networking. With VMware's purchase of Nicira (an OpenFlow implementation company), SDN was thrust into the popular tech culture hall of acronyms. At CohesiveFT we have been one of the companies driving the SDN space forward with our production product VNS3 serving customers’ needs since 2008.

SDN is virtualization of the network layer, users can access the highly available network capacity resource pool in much the same way they have access to storage and compute. Networks can now be offered up as resources controlled by the application layer allowing customization of the virtual network specific to the application/topology use-case.

From the authors of OpenFlow: Enabling Innovation in Campus Networks, “Network virtualization, if done correctly, should be able to run any workload that is compatible with existing networks, over any type of hardware at any location. The following list of seven properties must be in place to gain these benefits. Without them, it is not possible to unlock the true potential of cloud.”

The seven properties in summary are:

  • Independence from network hardware
  • Faithful reproduction of the physical network service model
  • Follow operational model of compute virtualization
  • Compatible with any hypervisor platform
  • Secure isolation between virtual networks, the physical network, and the control plane
  • Cloud performance and scale
  • Programmatic network provisioning and governance

VSM: What are the key benefits of SDN technology?

PK: SDN benefits both the provider and the user. Providers can create a more homogeneous and accommodating resource for consumption. Users can customize virtual network based on their needs and requirements. No more interaction with the IT staff or worrying about the complexity and control of the distributed underlying network. Flexibility, agility and mobility at the network layer create opportunities for mass customization and innovation.

SDN provides:

  • Increased integration, governance and security
  • Simpler network design vs physical network
  • High availability
  • On-Demand scalability to response to changing demand
  • Multi-tenant Isolation

VSM: Where does CohesiveFT operate inside the stack?

PK: CohesiveFT operate in the application (or cloud user) layer of the cloud. The needs and concerns of the cloud service provider are distinctly different than the needs and concerns of the cloud service user (the application topology deployed to the cloud and its owner). We call this the service provider-controlled layers and the application-controlled layer. We choose the designation "application-controlled" because the term "user" or "owner" is confusing in this context. Does it mean the end user of a web application, the contract owner of the cloud relationship, the system administrator of one of the pieces of the application topology? We designate the application itself as the proxy for these "user concerns.”