Orchestration and Management Using CSO
The following management and orchestration information pertains to the hardware, software, and services of the CSO platform itself. Therefore, this discussion pertains mostly to those who are implementing an on-premises deployment of CSO. While the same elements exist in CSOaaS, subscribers generally have little need to understand the concepts discussed in these sections.
The Contrail Service Orchestration software implements SD-WAN and NGFW management and orchestration solutions. CSO is a scalable and cloud deployable multi-tenant software platform that abstracts the complexity involved in creating and managing network services. Essentially, CSO provides the automation and integration framework for the various components of the solution.
The CSO platform is metadata-driven and uses templates to represent network and resource services. It uses intent-based policies, designed to translate the higher-level business rules such as, “send traffic type a, destined for endpoint b, across link c” into repeatable actionable tasks and executes them under the control of a flexible orchestration engine.
Some key characteristics of the CSO architecture are shown in Figure 1.
These characteristics include:
Container-based, microservices architecture that allows each functional component to be independently deployed and scaled
Hierarchical central-regional services that can support a large number of network elements (VNFs, PNFs, etc.) across multiple geographical locations
An orchestration platform to allow full lifecycle management of network devices and virtualized network services, as well as monitoring and visualization
Open, plugin-based, multi-vendor VNF and EMS support
Standards-based REST API for OSS/BSS integration
Flexible deployment options such as on-premises, public cloud, and private cloud.
CSO software is built with multiple layers of abstraction for usability and scalability, as shown in Figure 2. The platform implements these layers using orchestration software and controller software.
The Service Orchestration Layer contains the Network Service Orchestrator. The orchestration software has a global view of all resources, including both virtual network functions as well as physical devices.
The orchestration software also enables tenant management, providing end-to-end traffic orchestration, visibility, and monitoring. In addition, Enterprise customers can login to a Customer Portal to enable and manage their own set of services on demand.
The Domain Orchestration Layer contains the Network Service Controller. The orchestration software works together with the controller to manage on-premises (CPE) devices. The controller provides topology and CPE lifecycle management functionality; it also monitors device and link status, and passes this information to the orchestration layer.
The two layers are connected using standard Web-based REST APIs, and both the orchestration layer and the controller layer expose their own sets of APIs, which can be used by any external OSS system to integrate with CSO.
Infrastructure Services and Microservices
CSO uses a fully distributed, docker container-based microservices architecture. The platform consists of several infrastructure services and microservices, which are deployed across the central and regional nodes. Each of these microservices can be independently scaled and deployed, to enable the overall system to scale as needed.
For HA deployments, multiple sets of microservices can be deployed to allow for the failure of orchestrator components. An overlay connection is used between the sets of services to allow for seamless communication of microservices.
Some important microservices include:
Tenant site and service management (TSSM): Provides APIs for tenant, site and service management
VNF manager: Provides APIs to manage virtualized networking services
Intent-based Policy and SLA management (PSLAM): Provides policy and SLA profile object management service to enable SD-WAN functions.
Routing manager: Provides APIs to manage routing operations such as creating VPNs, interfaces to vRRs, enabling routing on CPE devices, etc.
Telemetry: Provides APIs used by fault monitoring and performance monitoring system for collecting service check results from telemetry agents.
Activation service: Provides network activation functions to enable zero touch provisioning of devices.
Installation and upgrade of CSO do not apply to CSOaaS. The information on microservices can be found in the CSO Installation and Upgrade Guide which is specific to the latest on-premises version of CSO which is 5.1.0