Given the system boundary drawn around the network, network planning and design treats the demand on the network as immutable and focusses on creating a network topology that will handle projected demand. Similarly, system capacity management is concerned with providing enough computational resources to handle application workloads while largely ignoring the network - treating it as a uniform "cloud" that will support the whatever demand is placed on it.
The move to scale-out applications, virtualization and convergence aims to improve efficiency by creating a flexible, scalable computing infrastructure that can adapt to changing demand. However, these architectural changes challenge the traditional separation between network and system management. For example, the following diagram shows how moving a virtual machine can dramatically alter network traffic.
|Figure 1 Moving a virtual machine can increase network traffic|
Redrawing the system boundary to include the network, servers, storage and applications provides the increased span of control needed to deliver efficient cloud services. For example, instead of treating the demand on the network as immutable, it becomes possible to move virtual machines in order to reshape network traffic patterns.
|Figure 2 Moving a virtual machine to reduce network traffic|
The sFlow standard is well suited to automation, providing a unified measurement system that includes network, system and application performance. The Data center convergence, visibility and control presentation describes the critical role that measurement plays in managing costs and optimizing performance.