Software Defined Networking: Now, Never, Don’t Know? Part 8

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In part 7 of this series on SDN, I discussed the technical and organization changes companies will need to make for a successful SDN deployment. Now let’s cover network visibility requirements.

One of the key requirements for a successful SDN will be comprehensive, deep, network visibility.  With the dynamism of network overlays that SDN offers, there are many new challenges that SDN monitoring tools will need to address:

  • Traditional elemental monitoring will still be required – link level utilization, device availability / reachability, elemental health metrics – e.g., CPU and memory utilization, fan, PSU and module status monitoring, etc.
  • Performance issue localization – when an application performs poorly, is it the application or the server or the network?
  • Application flow visibility – where is the application flow traversing, how are the devices and links along the path performing, is there any congestion, can a better path be selected?
  • Proactive monitoring – if a link is getting congested, which application flows are being impacted, or likely to become affected based on baseline traffic variation?
  • Configuration change detection, verification and notification.
  • RBAC awareness.
  • Relevant network protocol support – e.g. VXLAN routing.
  • SDN controller integration to garner topology, overlay configurations, etc. This may require support for a range of SDN controllers.
  • Capacity planning – this becomes more complex with SDN routing – e.g. with sub-optimal routing there are many possible paths between two end-points so the available capacity needs to be derived as a potential aggregate, similarly spare capacity between two end-points depends on which other overlay networks are passing traffic along shared links.
  • Security monitoring will change with the advent of distributed firewalls, IDS and IPS and their dynamic, distributed location. Protection of SDN control traffic (northbound and southbound) will be essential, as will security provisioning of applications using northbound APIs.
  • The dynamic nature of SDN and virtualization technologies in general places additional demands on management and monitoring tools in terms of the timeliness of the data they present and their ability to perform historic replay.
  • Given the complexity and path-oriented nature of SDN, network path visualization will become essential.

In part 9, I’ll discuss whether now is the right time for most organizations to adopt SDN in their network environments.


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