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The first recommendation I would like to highlight prior to go deeper through the different articles is, don’t extend the layer 2 segment beyond your physical DC if you don’t need. Keep in mind that for a better cost containment while maintaining easier IT operation, it exists different solutions to geographically (cold) migrate an application, while maintaining the same platform identifiers without extending the LAN across long distances – e.g. LISP IP mobility across subnet mode. We also need to take into consideration the distances and the transport – e.g. A dedicated 3 km fiber link between 2 DC does not necessarily suffer from the same challenges than deploying a layer 2 pseudowire or overlay over long distances.
Distributed Virtual DC aka DC Interconnect concerns not only the extension for Layer 2 to offer a solid and transparent interconnection for workload mobility (disaster avoidance), but Layer 3 transport may also be required for IP mobility, business continuity (disaster recovery) as well as intelligent IP localization services to improve the path optimization.
– Do I really need to extend my subnet outside my data center ?
– Can Layer 3 help to support application mobility between sites without LAN extension ?
– When and how can we optimize the traffic to and from outside the DC or between application tiers after a move of a machine.
I tried to summarise in the following articles most of the components and requirements imposed by Interconnecting resources spread over long distances in the following paper:
Let’s go step by step on the different topics (IP Mobility, LAN Extension, SAN Extension and Path Optimization) to provide you details on each technology and above all to allow you guys to comment based on your experiences or just feel free to ask any question if you need.
Having said that, please feel free to use this blog to also provide your experiences interconnecting geographically dispersed resources between multiple data centers.
With the evolution of the DC Fabric network, I am also going to add some articles on Intra-DC Fabric solutions and how DCI solutions evolve and will evolve to better support spanned Apps resources from site to site.
Keep cool and don’t be shy, it’s a friendly blog 🙂
Remember that above all, because the speed of light is greater than the speed of sound, some folks appear brilliant before they sound like an idiot !…