The telecommunications industry's ongoing "softwarization" transformation -- which combines software-defined networking (SDN), network functions virtualization (NFV) and cloud -- includes a number of difficulties that make many operators struggle to kick start real deployments. Below I list the top ten technical challenges operators face as they move to SDN, NFV and cloud.
Some of these challenges actually focus on ensuring operators meet the core requirements of a telecom network in today's software world. These include reliability, scalability, interoperability, standards and security. Since most SDN, NFV and cloud deployments are not greenfield, having to address existing infrastructure complicates the matter. (See How 'Softwarization' Changes the CSP Landscape)
Automation vs. SDN
SDN has come a long way since it started at Stanford University in 2005. Once full of hype, a couple of years ago the focus shifted from SDN as the end-goal to automation, which I think is a more practical target for operators. Providers now realize there's no magic bullet. However, network automation is here to stay, even on traditional networks. Operators will slowly start looking at achieving network automation, with the support of SDN and many other possible approaches.
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Centralized control vs. dynamic real-time networking
Carrier-grade reliability is key to all operator platforms, networks and systems. However, SDN's centralized control and intelligence concept challenges the dynamic real-time networking requirements the forwarding plane and the service running on top of the forwarding plane expect. Achieving the desired control plane to forwarding plane communication delay requirements in large operator networks is challenging.
True open, interoperable equipment
Adoption of SDN, NFV and cloud by the industry in general and operators in particular largely depends on the true openness of hardware and software components that build both physical and virtual underlying environments. Given that vendors are in a competitive business, their true willingness to truly be open is not necessarily obvious. In reality, multivendor integration and management for different modules and solutions is complex and difficult.
Orchestration vs. OSS
When it comes to integration in a multivendor, multi-layer and multi-technology environment, orchestration can be the elephant in the room. Referred to as Lifecycle Service Orchestration (LSO) by MEF, automated lifecycle management and orchestration of end-to-end services across physical and virtual infrastructure are not easy (even though they can be simply explained on PowerPoint). As services move from virtual network functions (VNFs) in virtual machines (VMs) to containers, operators will need orchestration of containers. The future of operations support systems (OSS) in a world of orchestrators is also challenging. Moving from today's OSS to NG OSS (next-generation OSS) to an OSS-orchestrator hybrid environment to fully orchestrator environment is even more difficult.
Are standards complete?
Open source has unofficially become the de facto standard for the implementation of virtualized, cloudified and agile platforms to realize softwarization goals. However, these standards and those coming from traditional standards development organizations seem incomplete. Even though open source follows fast iterations and improves standards dynamically, operator adoption of such agile methodologies, including DevOps, is difficult. Are we ready to take a risk with partly completed standards?
Security once was the biggest challenge facing cloud adoption and, for some, it still is. Security in the software world is inherently challenging to achieve when compared with the hardware world. Migration to virtualized platforms modifies the threat surface, introducing new factors. As many components in the operator environment become virtualized, softwarized and cloudified, security concerns surrounding infrastructure, platforms and services become paramount. We should always remember that telecommunications networks are critical national infrastructure in most countries -- and protect them accordingly.
Scarcity of examples
We have more NFV use cases (such as vCPE, vE-CPE, vIMS, vPE, vNAT, vFW, vEPC and so on) than SDN use cases. There are fewer use cases practically implemented in operator environments, although many providers and vendors speak about possible deployments. Wide adoption of use cases is essential for the future of softwarization adoption.
Coexistence of PNFs and VNFs
As operators migrate from old-generation networks of time division multiplexing-based circuit switching networks to next-generation networks (NGN) of IP- or Ethernet-based packet switching networks to the future software generation networks (SGN), we consistently come across brownfield deployments of new technologies and capabilities. Operators inevitably must deal with both physical network functions (PNFs) and VNFs in the migration from NGN to SGN; they also may need to manage PNFs within an SGN for a good while. Although dealing solely with PNFs (like today) or VNFs is somewhat easy, a mixed environment is difficult because of integration, interoperability, testing and service orchestration issues across different NFs.
Performance monitoring and reliability
The softwarized world still needs traditional FCAPS (fault, configuration, accounting, performance and security) functions but processes and implementations will change. Complexity will increase, requiring a higher degree of automation for operations administration and management. As networks and services run more autonomously -- often on a real-time basis -- management of changes in VNFs or clouds will be more dynamic than the management of static network elements.
Service and network testing
All operators rely on service, network and system testing. Providers are accustomed to traditional testing methodologies using test equipment and procedures with user-to-network interfaces and network-to-network interfaces on physical interfaces or ports. New vUNIs and vNNIs on virtual interfaces and ports need different test methodologies, procedures and tools. New ways and tools equal new challenges.
As the industry progresses and as operators move to softwarization, we must keep our eyes open on the changes around us and how we handle these (and other) challenges. More open, collective and collaborative approaches by operators, vendors and standards organizations surely will result in quick and sustainable outcomes that benefit the entire industry, from operators to vendors to subscribers.
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— Anuradha Udunuwara, senior engineer at Sri Lanka Telecom, is a frequent speaker at industry conferences, including Broadband World Forum.