Complex management of virtualised networks

“…the SDN idea is to separate out the control functions of the network into a cloud-like management layer leaving network elements in a data-forwarding layer. This means the smart component of networks can be made more efficient and less expensive by making use of the concepts of abstraction, modularity and virtualization that are already common in the IT world. At the same time the basic network building blocks – essentially the bit-carrying hardware – can be less expensive because they will become simpler and dumber.”
Esmeralda Swartz on the Metratech blog.

In yesterday’s blog, I spoke about the extra complexity that an OSS would need to manage in a virtualised environment that had hierarchies such as:

• A physical device to
• Hypervisor to
• Virtual Machine (VM) and Operating System (OS) to
• Logical device to
• Logical network interfaces to
• Interconnectivity between logical interfaces as well as
• Inter-relationships of physical devices with other assets such as storage, physical network interfaces and interconnectivity between physical interfaces.

To abstract that complexity from the OSS layer, it would seem to make more sense that:

• Service orchestration would be instantiated by the OSS, but an intermediate system (equivalent to an EMS/NMS) would handle the complexities of the dot-points listed above
• The OSS would take performance, inventory and alarm feeds from the EMS that represent rolled-up high-level identifiers (eg virtual devices), but there is an underlying hierarchy of attributes that allow the OSS to drill down into the deeper layers (eg to identify that the root cause of a virtual device failure is because its VM failed and needs re-building)