Network automation – Orchestration concept , components and …

What is a network orchestrator?

 A network orchestrator is a system that automates the provisioning and management of network resources. It provides a unified view of the network and allows administrators to manage it as a single entity.

Network orchestrators can be used to provision and manage virtual networks, physical networks, and hybrid networks .The network orchestrator must have a deep understanding of the network‘s topology and how the various components interact with each other. They must also be able to identify and resolve problems quickly, and be proactive in preventative maintenance.

Why use a network orchestrator?

Network orchestrators can help simplify the management of complex networks. They can automate many of the tasks that are required to provision and manage network resources. This can free up administrators to focus on other tasks. In addition, network orchestrators can provide a higher level of visibility into the network and can help identify and resolve problems more quickly.

What are the benefits of using a network orchestrator?

There are many benefits to using a network orchestrator. Some of the most notable benefits include: 

•Improved visibility into the network

•Reduced management overhead

•Faster problem resolution

•Improved agility 

•Higher quality of service

•Greater control over network resources

Components for an Network Orchestrator

Orchestrator Manager:

A network orchestrator manager usually operates at north bound , sometimes at OSS layer but mostly as middle ware technology or as east bound system. Its primary task is to communicate with south bound (network devices) via various protocols and then provides an API interface for other systems to build on top of it.

Orchestrators manager needs to communicate with south bound elements periodically before it can take decisions based on network data. There are various ways (*note – not all are required and some of below are redundant solutions achieve same result) it can collect or push data to network devices:

1. Netconf – netconf uses XML templates to configure or subscribe (pull) right configuration parameters from network device yang model. This needs a netconf agent configured at network device side.
2. Restconf – uses HTTP calls , like that of API calls, for pulling yang data. It is agent less procedure.
3. gNMI – gRPC network management interface uses google protocol buffers to pull yang model details from network devices. It needs an agent configured at device side.
4. ConfD – It is based on SSH/cli and uses existing processes of configured or accessing network devices. These implementations mostly require vendor specific cli command creation modules (e.g., NED – Network Element Driver- in case of Cisco NSO implementation based on confD/SSH)
5. southbound layer – network layer, is the legacy network devices layer which is still running data plane for real forwarding of data.
6. for network topology, orchestrator may either use any of above procedure to collect LLDP or any other output from device OR it may use another system to make BGP-LS session to have more advanced network topology creator (based on link state)