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SDN Migration. It’s Time.

Jan 26, 2015
Sue Kim - gu
Sue Kim - gu About the author

Mike McBride provides a case for making a smooth migration to open SDN.

Yellowtail is a much sought-after fish here in the ocean waters of Southern California. Their migration typically follows the water temperature changes from the tip of Baja into Southern California. The water temperatures have been unseasonably warm this winter, so yellowtail are abundant. And yummy. Not all yellowtail migrate, however. Many remain behind, year- round, as "guard" fish in places with a decent supply of food. They just don’t want to make the change to a better place.

But what do yellowtail have to do with SDN and the new approach to networking? Like guard fish, many network operators resist migration to more efficient, cost-saving, and service-enhancing environments due to a variety of concerns including familiarity, investment protection, and risk aversion. These are all valid reasons. The migration to SDN can be a daunting and challenging task. However, the more time spent answering certain questions, planning, and studying the successful migration of others, the greater the mitigation of fundamental concerns. Questions to be asked ahead of time include:

  • What are my goals for migrating to open SDN?
  • What are the initial steps I should take to achieve my goals for SDN?
  • What are my migration options?
  • How have others performed the migration?

ONF is tackling these difficult questions within the Migration Working Group and has produced a detailed whitepaper with its findings in the “Migration Use Cases and Methods” document. A summary of these findings can be found in the “SDN Migration Considerations and Use Cases” document.

SDN migration use cases fall into three main categories: legacy-to-greenfield, legacy-to-mixed, and legacy-to-hybrid. Greenfield scenarios are the least complex because there is no need to support integration or interoperation with an existing traditional network infrastructure. With legacy-to-mixed, new OpenFlow® devices are deployed and co-exist with traditional switches and routers, and they interface with legacy control planes. OpenFlow® controllers and traditional devices need to exchange routing information via the legacy control plane. With a legacy-to-hybrid network deployment, hybrid devices interface with both OpenFlow® controllers and legacy control planes. Each of these categories has been analyzed in detail along with several real-world migration use case studies including Stanford University’s campus migration to OpenFlow, Google’s Inter-Datacenter WAN use case, and NTT’s migration of BGP to OpenFlow® on the Provider Edge.

There are also several general and functional characteristics of tools which, if considered properly, can determine the success of migration from a traditional network to an OpenFlow-enabled network. General considerations such as security, scalability, and redundancy of tools, along with functional considerations describing data and information flow, input and output formats, and authentication of users, can help provide a smooth migration including quick diagnosis and troubleshooting of issues.

Enabling new services is an important motivation for SDN migration. These services need to overlay on top of virtual networks, span several network segments, and/or cross several layers of networking technologies. Pre and post migration checklists, along with the tools and guidelines ONF provides, will help facilitate a smooth migration of these services across the infrastructure. There is value in examining use cases across different network types, to better understand unique migration strategies. Various tools and methods exist to help network operators gain the confidence necessary to migrate to a network which is programmable, open, maintainable and valuable. The time is now to stop “guarding” your infrastructure and instead begin the migration steps to open SDN.

- Mike McBride, Director of Technology, Ericsson

As Director of Technology at Ericsson, Mike leads SDN, NFV, and Cloud market development; architecture; standardization; and strategy with customers, partners, and across product lines. Mike works closely with North American carriers and partners in the joint development of next generation networks. Mike is a Huawei alum where he developed, directed, and promoted strategic network architectures surrounding SDN/NFV/Cloud. Mike is also a Cisco alum where he developed architectures; supported customers; and managed mobility, wireless, and video projects across business units. Mike currently serves as Deputy Area Director within ONF and as a Working Group Chair within the IETF.

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Sue Kim - gu