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From the whitepaper Accelerating Cloud Native in Telco
Figure 2-1: Example layers for cloud native infrastructurefrom "Cloud Native Infrastructure" by Justin Garrison and Kris Nova (ISBN: 9781491984307)
Pre-Validation. Historically, Network Functions have been developed and pre-integrated with well-defined infrastructure, which was known in advance. That pre-validation was done by a Network Function vendor and the system was delivered as a validated/certified bundle together with performance and stability guarantees. In the cloud native world, there are too many permutations which makes it impractical to follow the traditional certification path. However, Cloud Native Network Function (CNF) vendors are still sticking to it by picking a small number of opinionated infrastructure flavors (different from vendor to vendor!) to pre-validate against, making any infrastructure outside this selection too complicated, too costly, and too slow to deliver for CSPs. This creates problems in the adoption of those CNFs as CSPs generally prefer to each have a unified cloud native infrastructure layer, which they are free to choose and often it can differ from the opinionated infrastructure already validated by the CNF vendors.
Adaptations. CNFs are typically delivered as a collection of artifacts such as YAML, Helm charts, and container images. These artifacts are intended for deployment in CSP’s cloud native environment. However, every CSP has somewhat different rules, policies, security standards, API versions, and approaches to lifecycle operations (e.g. use of NFVO capabilities, GitOps pipelines, etc.). Due to that, it is often not possible to deploy the CNF directly in any environment in a consistently replicable way, but it requires some adaptations. That shall normally not pose a problem, as most of these adaptations can be performed in deployment configuration often in YAML files, by either CSP’s DevOps team or the vendor’s delivery personnel. Nonetheless, we often encounter situations where CSPs are not allowed to perform such adaptations (under threat of losing support if doing otherwise) since these artifacts are part of the release and could be adapted only in new release delivery or through the custom change request. As a result, this situation often leads to a frustrating cycle of discussions and significantly hampers the CNF onboarding process.
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Fragmentation of all layers and a need for change in the deployment model
This is a list of modified challenges based on a Sylva article. This Cloud Native Telecom program can be part of solving these solutions.
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source: https://the-mobile-network.com/2022/11/why-the-eu-big-five-are-launching-sylva/
Runtime interoperability of CNF platforms and CNFs
- CNF-s need to have some assumptions about their environment due to their resource needs (e.g.: multiple pod networks, network and compute latency). The assumptions have to be the same for all CNF platforms.
- To achieve interoperability the CNF platforms need to fulfill these assumptions.
- To ensure that the assumptions of the CNFs are correct and that the platforms fullfill the assumptions both the CNF-s and the platforms need to be tested
- There is no point in doing interoperability conformance testing of only one side, as the conformance will not have a target