Evaluating container-based VNF deployment for cloud-native NFV

The requirements of cloud native VNFs (virtual network functions) for telecom are different than IT applications – and VNF deployment using microservices and containers can help realising cloud-native NFV implementation success.

The best application for NFV is how it will be integrated, architected and further matured to strengthen 5G implementation for telecom service providers. Based on the current pitfalls related to VNF deployment and orchestration, making cloud-native VNF is the only solution in front of service providers today.

Yet telecom applications’ requirements of VNFs are different than any cloud-native IT application. Telecom VNF applications are built for data plane/packet processing functions, along with control, signalling and media processing. An error, or harm to VNF may break down the network and will impact the number of subscribers. Due to such a critical processing requirement, VNFs in telecom should be resilient, offer ultra-high performance, low latency, scalability, and capacity. Telecom VNFs need to be a real-time application having latency sensitivity to fulfil network data, control and signalling processing requirements.

Decomposition of cloud-native VNFs into microservices

VNFs are network functions-embedded software taken out of network peripherals and hosted on virtual machines as an application. Any kind of update to VNFs raises a time-consuming manual effort which hammers overall NFV infrastructure operations. To get ready for cloud native, bundled VNF software needs to be microservices-based, wherein monolithic VNFs are decomposed into different smaller sets of collaborative services having diverse but related functionalities, maintaining their own states, having different infrastructure resources consumption requirements, should be communicated, automatically scaled and orchestrated using well-defined APIs.

There are various benefits of microservice-based VNF decomposition:

  • Decomposed VNF sub-services are deployed on hardware which is best suited to be efficiently run and managed. It can scale as needed
  • Any error or glitch in the microservice causes failure to only that specific function, which allows easy troubleshooting and enables high availability
  • Decomposition allows reusability of service within VNF lifecycle in NFV environment. It also allows some services to get rollout quickly
  • Whole VNF becomes lightweight as functions like load balancing and deep packet inspection (DPI) are stripped out from the core application

As VNFs get divided in microservices, service providers may face operation complexity as the number grows. To manage all microservices well in production environment, high level automation needs to be implemented with NFV MANO layer and cloud orchestrator.

Evaluating deployment method of VNF using virtual machine and containers

Containers are a form of virtualisation at the operating system level. It encapsulates application dependencies, required libraries and configuration in a package which is isolated from other containers in the same operating system. Containers allow applications to run in an independent way and can be easily portable.

As a move towards cloud-native, VNF microservices can be deployed in containers which enable the continuous delivery/deployment of large, complex applications. But this approach is still in the early stage for cloud-native NFV.

Concerns with using containers for VNF

To use in NFV, there are certain concerns of using container technology:

  • The ecosystem is still evolving and immature compared with virtual machines
  • Security risks are involved with containers – all containers in OS share a single kernel, any breach on kernel OS breaks down all containers dependent on it
  • Isolating a fault is not easy with containers and a fault can be replicated to subsequent containers

Service providers who may want to use containers in an NFV environment may face challenges in multi-tenancy support, multi-network plane support, forwarding throughput, and limited orchestration capabilities. It is still possible to use containers in mobile edge computing (MEC) environments, which is going to co-exist with NFV in 5G in the future. MEC will be taking user plane function near to the edge of the network, closer to user application to provide very low latency, agility and enable real-time use cases like IoT, augmented reality, or virtual reality.

Containers can possibly be used along with virtual machines in an NFV environment as well. The deployment of VNFs can be virtual machine only, containers only, hybrid – where a container will run in virtual machines providing security and isolation features – and heterogeneous mode, where some VNFs will run in VM, some in containers, alongside a mix of both.

Service providers can evaluate their deployment methods as per their requirements at NFV infrastructure level.

Benefits of containers for cloud-native NFV path

Having a container in place to host microservices can allow active schedule and management to optimise resource utilisation. Container orchestration engines enable provisioning of host resources to containers, assigning containers to hosts, instantiate and reschedule containers. With containers, service providers can realise successful implementation of DevOps methodologies, allowing ease in automation tasks like scaling, upgrading, healing, and become resilient.

A major benefit of containerised microservices is the ability to orchestrate the containers so that separate lifecycle management processes can be applied to each service. This allows for each service to be versioned and upgraded singularly, as opposed to upgrading the entire VNF in virtual machine. While upgrading a whole application or VNF, a container scheduler determines which individual services have changed and deploys only those specific services.

Containers enable cloud-native ability into NFV infrastructure with added performance, portability and agility benefits, for telecom-specific application deployment and orchestration. To have fully featured cloud-native 5G networks, it is imperative for service providers to have containers to deploy more than virtual machines. But service providers will seek further research and development from open source communities like ONAP and OPNFV.

How containers impact NFV at application, infrastructure, and process levels

Applications (VNFs):
– It packages microservices along with its dependencies, libraries and configuration, and make it isolated
– Containers can build quickly with existing images in place for microservices
– Enables faster time to market due to highly automated deployment
– Programmable API enables a complete DevOps approach to be implemented with VNF development, deployment and lifecycle management

Infrastructure (VNF orchestration):
– Containers are portable packages which can move from one environment to another
– Containers can scale in/scale out as per requirement at NFV infrastructure
– Enables higher density
– Enables multi-tenancy to serve multiple requests
– Ease in upgrades and rollbacks as containers allow versioning

Process (VNF deployment):
– Containers can be immutable and can be pushed to any platform
– Allows smooth transition from dev to test to ops
– Enables highly efficient automation
– With containers, service providers can drive continuous integration/deployment to VNF onboarding and lifecycle management

Containers play a vital role on the path to achieve a complete 5G network built with highly automated cloud-native NFV. Successful deployment of 5G will depend on how service providers build a strategy around usage of containers in NFV infrastructure. Aside from the security risks involved in using containers, there might be use case challenges of containers in telecom applications that demand much higher performance. Containerisation can be possibly implemented in mobile edge computing to provide its benefits, but full integration will be expected by service providers to enable cloud-native NFV.


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