modernizing the OSS approach for Virtual Infrastructure

www.hcltech.com
modernizing
the OSS approach
for Virtual
Infrastructure
WHITE paper
Table of Contents
Introduction
3
Traditional OSS approach
4
Need for OSS evolution to support Hybrid Networks
5
Service Fulfillment - Agile design and creation of new services
5
Service Assurance - Real time operation
6
Fault Management
6
Performance Management
7
Inventory Management
7
OSS Integration architecture for Hybrid Networks
8
Use Case 1 – Fulfillment – Service Fulfillment Agility
8
Use Case 2 – Fulfillment - Up-to-date Inventory
9
Use Case 3 – Assurance – Real time Fault Management
9
Use Case 4 – Assurance - Real time Performance Management
10
Benefits of this approach
10
Introduction
Traditional Operational Support Systems (OSS) are a set of programs that help a communications service
provider (CSP) monitor, control, analyze, and manage a network. OSS solutions are composed of
disparate functional units for managing different parts of the network.
With the advent of Network Function Virtualization (NFV) and Software Defined Networking (SDN), the
complexity of management and operations, and associated Operational Expenditure (OPEX) of virtual
networks is reduced. In a practical scenario, a network will be comprised of physical and virtual Network
Elements (NEs), a.k.a “Hybrid Networks”. While complete migration to virtual infrastructure is a long term
goal, service providers are looking for service monetization through agility and automation in end-to-end
service fulfillment, improved resource utilization (which reduces operational costs), and improved customer
experience in hybrid networks. This introduces new operational scenarios for OSS and implies changes to
the current network operations models and OSS solutions, to align with the benefits offered by these new
technologies.
This white paper will cover the gaps in traditional OSS systems and existing challenges that need to be
overcome for achieving the goals of the service provider. This paper proposes an integrated architecture for
addressing these issues, which can be considerered as a modernized approach for achieving end-to-end
agility and programmability of hybrid networks.
Traditional OSS approach
Traditional OSS systems handling legacy networks do not follow a standardized approach in the
management of physical NEs. These OSS solutions work in silos, each focusing on specific functions (e.g.
inventory, performance assurance and monitoring, trouble ticketing, service configuration and activation,
fulfillment, test and diagnostics, etc.). These systems do not have the capability to abstract the end-to-end
network and map service to underlying network resources. Inventory information is not centralized and is
maintained in different forms in different locations. All these contribute to lack of agility and automation in
service delivery.
Need for OSS evolution to support
Hybrid Networks
Next Generation OSS (NGOSS) is the TeleManagement Forum (TM Forum) business solution framework for
creating next generation OSS software and systems. It delivers a framework and a repository of models and
guidelines to facilitate rapid development of flexible OSS solutions to meet the business needs of
telecommunication environment. With the adoption of Software Defined and NFV based service function
deployments, the needs for flexibility in the OSS systems have increased further.
Traditional OSS Systems have been existing in the market for many years – hence it involves a lot of
investment and effort for OSS vendors to align with the NGOSS standards. This in turn implies that service
providers will not be ready for leveraging the SDN/NFV benefits in the near future.
An alternate solution for addressing the gaps is an architecture that deploys a “mediation layer” in hybrid
networks that is capable of interacting with different NEs and the OSS. This approach does not involve
major re-design of OSS solutions. However, this integration architecture needs to address several
challenges from the OSS perspective, in order to be able to offer complete benefits for service providers
and end customers.
Service Fulfillment - Agile design and creation
of new services
One of the important precepts of NFV and SDN is the ability to rapidly create new services. Service fulfilment
is critical while services and the fulfilment environments have become more complex. End-to-end fulfillment
involves automation, right from customer order to activation across multiple service stacks.
For rapidly creating new services, the OSS should map the services to physical resources and automate
provisioning of physical NEs. From the NFV perspectiveOSS should facilitate rapid on-boarding of new
VNFs / Service Functions and associated catalogues. In SDN enabled environment, OSS needs to
orchestrate SDN controllers as well. Thus, OSS should enable end-to-end provisioning of services despite
disparity and complexities of hybrid network.
Service Assurance - Real time operation
Traditional OSS systems are not real-time, i.e. they do not adapt to a constantly changing network
environment in response to planned and unplanned network events.
Fault Management
To support the dynamic, ever changing NFV environment, OSS must work in near-real time and be able to
recognise the changes to the network configuration as and when they happen. It must also provide visibility
of faults across all domains and vendors, to ensure a holistic view to support assurance of dynamically
changing services. With this availability of real time data, it should be possible for service providers to quickly
identify and fix the source of service disruptions in several disparate and dynamic networks, before
customer complaints are raised.
Performance Management
OSS needs to display real-time statistics and performance of service related data traversing the entire
network. Based on this data, it should provide the ability for service providers to analyze and characterize
service function usage to plan effectively, handle growth, support service level agreements (SLAs), and
avoid unnecessary capital expenditures. Real-time statistics for each subscriber are critical to understanding service efficiency and improving service quality. The OSS should display real time metrics to evaluate
and improve service quality and proactively avoid network performance deterioration. Based on Key Quality
Index (KQI), service providers should be able to isolate and locate root causes that influence service quality.
Inventory Management
For agility in service fulfillment and real time fault and performance management, it is critical for OSS to
maintain up-to-date inventory of physical and virtual resources. The virtual environment is dynamic, i.e.
Virtual Network Functions (VNFs) are instantiated, scaled out, scaled in, and terminated frequently. The OSS
needs to maintain up-to-date inventory regarding virtual resources in this dynamic environment, while also
maintaining accurate and centralized inventory regarding physical NEs.
OSS Integration architecture for
Hybrid Networks
The OSS Integration architecture involves a Higher Order Orchestrator (HOO) which acts as “OSS
Mediation Layer” that interfaces with OSS, legacy, and virtual networks.
OSS
Modules
The diagram depicts various OSS modules interfacing with HOO. The HOO plays the key role of bridging
disparity between different networks, and translating the requests between OSS and different Service
Functions and NEs. The HOO will need to interoperate with the following entities:
North Bound towards OSS:
The HOO interfaces with:
Performance Management system to ensure real time update of performance and quality metrics in
different parts of the network.
Fault Management system to propagate service faults in real time.
Service Provisioning module to push service requests to Service Functions and NEs.
Inventory and Topology Management System to update the changes to resources on a real time basis, to
maintain up-to-date inventory.
ELEMENT MANAGEMENT SYSTEM (EMS) / NETWORK MANAGEMENT SYSTEM (NMS) for
interfacing with physical network elements.
NFV Orchestrator (NFV O) / VNF Manager (VNF M) which further interworks with VNFs. NFV O
interworks with Virtual Infrastructure Manager (VIM) and VNF Managers. The HOO interacts NFV O / VNF
M for onboarding, instantiating, and orchestrating VNFs upon requests from the OSS.
Hybrid Network Orchestrator/SDN Controller for SDN enabled NEs.
The HOO will need to handle the definition and design of ‘Service Models’ and possess the capability to
map the service model to resource model and identify the NEs for realizing the service. It will rely on an
up-to-date Inventory Management module for verifying the resource availability. The design and definition of
Service Models is the key capability for achieving end-to-end automation in service provisioning. Apart from
the initial definition of service, the HOO will also need to handle dynamic changes to service configuration.
This is further illustrated the following use cases:
Use Case 1 – Fulfillment – Service Fulfillment Agility:
For agility in service fulfillment, the NFV Orchestrator should facilitate ease of provisioning and onboarding
of VNFs. This requires the OSS to automate the provisioning of physical NEs; HOO requires interoperating with OSS’s existing provisioning system to facilitate end-to-end automation.
Figure 2 illustrates how end to end Service Provisioning can potentially be handled in the integrated
architecture.
The operator configures a service through the OSS Service Provisioning user interface. The Service
Provisioning module pushes this information to HOO.
HOO identifies NEs for realizing this service and looks up inventory to segregate requests to physical NEs
and VNFs.
HOO propagates
A. VNF related requests to NFV Orchestrator
B. Physical NE related requests to EMS/NMS
C. Network Interface specific provisioning requests to Hybrid Network Controller
NFV Orchestrator on boards the VNFs and updates its centralized catalogue. It allows the provisioning of
VNF descriptors and performance parameters in a standardized format
NFV Orchestrator requests the Virtual Infrastructure Manager to allocate resources for the new VNF. It
requests VNF Manager to instantiate a new VNF
EMS/NMS configures the physical NE
The Hybrid Network Orchestrator pushes network interface specific provisioning requests further into
NEs.
Use Case 2 – Fulfillment - Up-to-date Inventory:
Virtual Network Functions are instantiated, scaled out, scaled in, and terminated dynamically. NFV
Orchestrator needs to maintain up-to-date inventory information in this dynamic environment while the OSS
needs to maintain up-to-date inventory regarding physical NEs.
Figure 3 illustrates how the inventory can potentially be made up-to-date during dynamic Service
Function/VNF instantiation and termination.
In response to a request for instantiation / scaling out or termination of a VNF, the provisioning system and
HOO pushes this request to Higher Order Orchestrator and keep each other in sync
HOO propagates this request to NFV Orchestrator/ VNF Manager
The VNF Manager interacts with VIM to allocate additional physical resources for the VNF
NFV Orchestrator requests the VNF Manager to create an additional VNF instance
After successful completion of this activity, the NFV Orchestrator informs the HOO
The HOO in turn conveys this to Inventory and Topology Manager. The inventory information in OSS is
made up to date.
Use Case 3 – Assurance – Real time Fault Management
Alarms are reported in various layers of NFV – the NFV Orchestrator requires to perform alarm correlation
and propagate this information to OSS. The Higher Order Orchestrator needs to subscribe for alarms from
physical NEs and collect alarms on a real time basis. HOO needs to correlate alarms reported from physical
and Virtual NEs / Service Functions.
Diagram 4 illustrates the potential sequence of events that can be modeled when faults are reported from
physical and virtual service functions, and the same needs to be correlated for dynamic service assurance
requirements.
Alarms are reported for faults in different layers (i.e. physical, virtual and in the VNF) of NFV - Virtual
Infrastructure Manager propagates alarms related to virtual and physical layers to NFV Orchestrator
VNFM propagates alarms related to VNF to NFV O
NFV O performs alarm correlation for certain faults and pushes this information to Higher Order
Orchestrator
HOO subscribes and receives alarms from EMS/NMS and network related alarms from Hybrid Network
Orchestrator on a real time basis.
HOO correlates and propagates these alarms to the Fault Management Module. The OSS Fault
Management Module performs correlation of alarms received from various sources to identify the root
cause, and displays appropriate information to the technician for corrective action. The fault correlation at
OSS helps understand how resource failures at NFV impact network services and subscribers and enables
optimization and effective utilization of physical resources. This facilitates proactive analysis of faults even
before a trouble ticket is raised by the subscriber, thereby avoiding service degradation.
Use Case 4 – Assurance - Real time Performance Management
NFV O aggregates performance metrics from virtual NEs and reports them in real time. This requires the
OSS to collect performance measurements from physical and virtual Service Functions / NEs in real time
and be able to perform end-to-end correlation and predictive analysis of service consumption trends.
Figure 5 illustrates the potential sequence of events that can be modeled for real time analysis of
performance and quality metrics.
The Performance Management module of OSS initiates periodic collection of performance metrics in the
network
The request is routed through the Higher Order Orchestrator which looks up the inventory and topology
manager to identify the NEs
Higher Order Orchestrator splits requests for NFV orchestrator, Hybrid Network Orchestrator, VNF Manager
and legacy EMS/NMS, and requests for the collection of performance metrics of each system
The NFV Orchestrator requests VNF Managers and VIMs to collect data from VNFs, Hypervisors, and
physical resources. The EMS/NMS requests this information from Physical NEs. The Hybrid Network
Orchestrator requests this information from Physical/virtual NEs
The VNFM/NFV Orchestrator, Hybrid Network Orchestrator, and NMS perform aggregation of performance
metrics and respond to HOO. The HOO computes the service metrics and service quality index and feeds
this information to OSS Performance Management module
The HOO feeds this information to Data Analytics module, which utilizes the current metrics along with
previously collected information to perform predictive analysis
The OSS Performance Management module displays the service level metrics along with predictive
analysis results in OSS GUI. This contributes to service quality improvement and enables proactive network
maintenance and optimization.
Benefits of this approach
The operator’s services environment will adopt both physical and virtual service functions for the foreseeable future, and legacy OSS systems will require mediating layers to interwork with the evolving services
infrastructure. This paper discusses some of the top use cases that get addressed by such OSS mediating
layers.
The following diagram explains the positioning of these use cases against TM Forum’s eTOM framework,
and identifies the perceived impact areas.
Dynamic Inventory Management and End-to-end Service Provisioning facilities over the evolved Services
Infrastructure establishes the Fulfilment capabilities for the Operator. While these facilities centre on Service
Management and Operations, the Service Model definitions supporting the complete deployment
essentially introduces the dynamic fulfilment abilities over further process areas for Supplier / Partner
Management, Revenue Management Operations, and Customer Relationship Management.
Service Model definitions around Real-time Management of Faults and Performance also centre on Service
Management and Operations. However, associated corrective and preventive actions introduces dynamic
assurance capabilities over Supplier / Partner provided services, Revenue Management & Operations, and
Customer Relationship Management process areas. In addition, the factors positively influencing Fulfilment
capabilities also develops indirect influence over Operation Support & Readiness and Billing, since related
Service Model definitions largely depend on the dynamic definition of services catalogue, inventory and
provisioning of the dynamic service functions. Similarly, factors impacting Assurance capabilities also
introduce correlated Service Model definitions indirectly influencing Operation Support & Readiness and
Billing.
References
ETSI NFV Management and Orchestration: http://www.etsi.org/deliver/etsi_gs/NFV-MAN/001_099/001/01.01.01_60/gs_NFV-MAN001v010101p.pdf
Next Generation OSS/BSS: http://www.slideshare.net/grazio.panico/ngen-oss-bss-architecture-evolution
How to avoid NFV transformation pains: http://www.vanillaplus.com/2015/01/20/4448-how-to-avoid-nfv-transformation-pains-part-2-tell-me-where-it-hurts/
How to drive NFV service agility and drive new service innovation: http://inform.tmforum.org/strategic-programs-2/agile-business-it/2015/11/how-to-deliver-nfv-service-agility-and-drive-new-service-innovation/
Author Info
Priya T G
Priya joined HCL in August 2014. She has extensive experience in CDMA, primarily in the areas of Security
(identification of vulnerabilities and architecting security solutions), Element Management, and Network
Management.
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