href="http://www.iste.co.uk/pujolle/software2.zip">www.iste.co.uk/pujolle/software2.zip
One difficult problem that is beginning to be considered is the urbanization of virtual machines that are in the datacenters. Depending on the optimization criterion, the time of day or the performance requirements, the virtual machines migrate so that they are located in the best possible place. Most typically, urbanizations are done for the purpose of saving energy, which tends to consist of grouping together the virtual machines on common servers, or for the purpose of optimizing performance, which involves the opposite operation – distributing the resources to the servers as much as possible.
It should be noted that in terms of networks, the optimum placement of the virtual machines is no longer an equal distribution between all the physical machines, but on the contrary, the filling of those physical machines with the maximum possible number of virtual machines, obviously without causing a degradation in performance. The other physical machines are placed on standby to save energy. In the networks, this involves sending the streams along common paths, rather than dispersing them in the infrastructure network.
The SDN market is fairly difficult to predict, because while demand is high, so too are the costs involved in making the move to this new architecture. These high costs are due to novelty and to the difficulty in integrating SDN into the existing networks. In particular, operators who possess a significant physical infrastructure are wondering about the integration of SDN: how can it be introduced without an additional costly structure? Indeed, it is not an option to demolish everything and rebuild from scratch in this new context. Therefore, we need to introduce SDN in specific environments such as the renovation of a part of the network or the construction of a new localized infrastructure.
Figure 2.18 gives an indication of what the SDN market could be in coming years. In this figure, we can see that there is a good distribution between service providers, the companies offering datacenter services, Cloud providers and, to a lesser extent, the companies’ access networks.
Finally, if we look at the manufacturers’ vision, we see two avenues, which are represented by VMware and Cisco: software-orientation and hardware-orientation. The software-oriented vision is installed on the physical machines of practically all manufacturers, while hardware-orientation is greatly favorable for manufacturers – especially well-established ones.
Figure 2.18. OpenFlow market, and more generally SDN market. For a color version of the figure, see www.iste.co.uk/pujolle/software2.zip
Even though today, the SDN is made for high capacity networks, there is a strong chance that it will become widely used on the periphery and that SDN will prove to be the right solution for controlling all peripheral devices. In particular, OpenFlow Wi-Fi access points are coming onto the market, and are likely to make their presence felt fairly quickly, with SDN following on in their wake. This will be the subject of Chapters 4 and 9. They focus on smart edge.
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