Network Infrastructure on Cloud

Author: Shantanu Bhattacharya, Co-founder and CTO at Phone Pass Pty LTD

Implication of network infrastructure on cloud

Network Infrastructure on Cloud - A few years ago, the basic idea of Software Defined Networks (SDN) was popularised. SDN was conceived as its proponents observed that network device vendors were unable to meet the pace of change required by the industry. The devices could be programmed only through the command line interface or using the Simple Network Protocol; neither met the evolving requirements for easily accessible, flexible, and application-friendly interfaces.

Some Stanford University engineers created OpenFlow protocol that could work with an architecture comprised of a number of devices containing only data planes to respond to commands sent to them from a logically centralized controller that held the control plane for that network. The controller was responsible for maintaining all of the network paths, as well as programming all the network devices it controlled. These communications were the essence of the OpenFlow protocol.

OpenFlow led to the conceptualisation of SDN. OpenFlow could even “transmogrify” these platforms to be any other network device. E.g., firewalls or NAT. This tectonic shift in the networking industry was well documented in several books. These books explained that SDN encompassed more than control and data plane separation and was more than a single protocol. SDN was thought to be about the problems of Network Programmability, and it was thought that SDN solutions needed a set of protocols. Since then, SDN technologies have advanced quite a bit and are now being deployed in production networks.

Some authors opined that the approach of brainless machines replacing each and every network element might not scale well in practice. These observations were based on concerns of both CAPEX and OPEX with a greenfield approach that required network operators to replace their existing equipment with newer ones in order to realize the benefits of SDN. However, many SDN deployments today are in fact “brownfield” networks that evolved by starting as “SDN ready” rather than having SDN enabled. This meant that most of the existing equipment was preserved until its scheduled lifespan was complete, while SDN capabilities were slowly added incrementally.

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Even in the recent past, network functions like firewalls and encryption could only be performed on dedicated hardware devices built for the purpose. Network Functions Virtualization (NFV) has allowed commodity servers to accomplish them. That resulted in significant advantages like cost reduction and speed of service deployment.

In an NFV, the virtualization layer operating system coordinates the compute and store. Further, it can connect resources shared among the Virtual Network Functions (VNFs) that could execute on the same physical server. The Management and Orchestration (MANO) component orchestrates and administers the VNFs. With ever-increasing demand for network bandwidth and services, virtual functions can be deployed at the right time and place as required.

What is NFV? How was it conceptualised?

Network Function Virtualization (NFV) could be conceived of use of some of the basic and prime concepts of SDN. These could include control/data plane separation, logical centralization, controllers, network virtualization (logical overlays), application awareness, application intent control, and many more on easily available (Commercial Off-The-Shelf (COTS)) hardware platforms. NFV has enhanced the conceptualisation of new methods in support of service element interconnectivity, and techniques that can cope with its dynamic requirements and their upscaling and downscaling.

The pressure on network operators increased in 2013 and grew into real challenges to their businesses.

What started as an Over-The-Top (OTT) video and social media into their broadband customer base, grew into OTT service offerings. The outsourcing of organisations’ IT to cloud providers turned these new competitors into more relevant IT partners.
Wireline operators faced large and long-delayed transitions in copper-based services.
Wireless operators faced an expensive architecture change in the move to LTE to accommodate the growing demand for data services. The pressure points here were the growing presence of Wi-Fi leading to exponential growth in demand, while competition meant that pricing had to drop. That meant increased pressure from traditional service providers’ investors to increase operational agility, particularly around service agility (reducing costs through automation, just in time provisioning, resource pooling, etc.) and innovation to avoid obsolescence. There were two intended results — to compete with the OTT threat and avoid relegation as mere transport providers and to provide new revenue sources.
Many operators with both wireline and wireless operations, needed to consolidate to cut costs and increase efficiency. Impacts were in reducing operational and capital expense (OPEX and CAPEX).
On another front, virtualization concepts evolved out of enterprise-centric virtual machine operations, to more composable and scalable components like containers in public and private clouds.
Virtualization infrastructure performance optimisation started receiving a massive adoption through efforts like Intel’s Dataplane Development Kit (DPDK)-enabled version of Open vSwitch (OVS)— resulting in throughput increase of virtualized network functions more easily achievable.
Cloud computing attracted more and more enterprise customers. In addition to COTS costs reduction, this also created an environment for more service outsourcing.

Before exploration of each of these areas to visualise their combination forming the basis for NFV, NFV should be defined. NFV is the process of network services design, building, and deployment using virtualized software components and their decoupling from the executing hardware. NFV orchestrates virtualized services and/or service components, and their physical counterparts. Hence, it can create, deploy, integrate, configure, change, and delete the services.

SDN is a component of NFV. It is the enabler of NFV, but not the other way round. With the advancement of orchestration and virtualization techniques in COTS hardware, NFV is gradually coming into vogue. There are many advantages conceived in production networks today. Like rethinking change it caused about the control plane, SDN concepts and components pressurise service providers to revalidate the assumptions of the current method - providing a service plane, delivering services using virtualized, flexible, and COTS hardware. Existence of SDN provides the required credibility.

Virtualization is not a panacea for all service deployment problems and actually introduces new reliability issues that a service orchestration system needs to mitigate. Virtualization, like any tool, deployed wantonly, can produce disastrous results. While virtualization is critical for NFV, the orchestration and integration required needs a scope that includes present and future fully integrated service platforms. In that regard, SDN can provide a “glue” for enabling middleware.

In spite of universal acceptance of SDN in the control of service virtualization, the type of control point or points will continue to be debated. For NFV, the debate manifests around stateless and proxy control points, or when inline or imputed metadata is employed.

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Pros and Cons?

Advantages of NFV

There are many benefits of implementing NFV as an alternative to standard architecture. Some of them are discussed below:

Lower CAPEX and OPEX
Increased ease of scaling the network up and down
Increased service agility to support speedier service rollouts
Enhanced operational simplicity
Faster innovation leading to elimination of hardware change need
NFV may be a viable revenue generator.
“While there are still challenges in using NFV to impact service velocity in a significant way, the technology can already enable a new range of service features that will be used to produce revenue,” according to Tom Nolle of CIMI Corporation.
Enhancement of data collection, analysis and business decision-making processes.

Disadvantages of NFV

NFV is based on SDN and thus has the same limitations. Like SDN, NFV needs further evolution to gain reliability when deployed at the enterprise level. But that is not too far away. Some of the other specific challenges facing NFV going forward include:

Co-existing in a cloud-integrated hybrid environment with physical devices
Unlike conventional IT environments, NFV requires managing IT in the abstract
NFV is more dynamic than the traditional environment, with possible requirement of scaling up while adding new features
NFV needs a process realignment for the simultaneous management of traditional and virtual infrastructure

Meeting the Challenges of NFV

The transition to network function virtualization will take time. There are some use cases where the adoption might be faster due to it being the need of the hour. Legacy networks are likely to remain in place for a period of time.

In order to meet the requirements of a transition towards virtualization, architecture must provide:

Support for dynamic, real-time network and service changes in response to network events
Separation of network configuration and management of network state
Support for a modelling approach to network services
Interworking with network orchestration platforms
Interworking with SDN controllers

It’s also vital to have a thorough planning of the migration strategy before one begins deploying network virtualization. Large enterprise networks will find more applicability here.

This can make replacement of existing infrastructure much more complex.

One way to mitigate this is through adoption of a hybrid environment in which the virtual networking capabilities are deployed in the areas where they offer the most perceived value or where legacy upgrade is required.

Conclusion

Network Infrastructure on Cloud - NFV is new concept and is quickly gaining popularity. It can potentially handle many of the challenges of current and future networks. However, like all new concepts, careful examination of new case is suggested along with gradual adoption to check the value provided by it before widespread adoption.