Reliable Server Pooling - Evaluierung, Optimierung und Erweiterung einer neuen IETF-Architektur

The Reliable Server Pooling (RSerPool) architecture currently under standardization by the IETF RSerPool Working Group is an overlay network framework to provide server replication and session failover capabilities to applications using it. These functionalities as such are not new, but their combination into one generic, application-independent framework is. Initial goal of this thesis is to gain insight into the complex RSerPool mechanisms by performing experimental and simulative proof-of-concept tests. The further goals are to systematically validate the RSerPool architecture and its protocols, provide improvements and optimizations where necessary and propose extensions if useful. Based on these evaluations, recommendations to implementers and users of RSerPool should be provided, giving guidelines for the tuning of system parameters and the appropriate configuration of application scenarios. In particular, it is also a goal to transfer insights, optimizations and extensions of the RSerPool protocols from simulation to reality and also to bring the achievements from research into application by supporting and contributing relevant results to the IETF's ongoing RSerPool standardization process. To achieve the described goals, a prototype implementation as well as a simulation model are designed and realized at first. Using a generic application model and appropriate performance metrics, the performance of RSerPool systems in failure-free and server failure scenarios is systematically evaluated in order to identify critical parameter ranges and problematic protocol behaviour. Improvements developed as result of these performance analyses are evaluated and finally contributed into the standardization process of RSerPool

A NEAT Way to do Network Programming

This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the author(s)Peer reviewedPreprin

On Robustness and Countermeasures of Reliable Server Pooling Systems against Denial of Service Attacks

Abstract. The Reliable Server Pooling (RSerPool) architecture is the IETF's novel approach to standardize a light-weight protocol framework for server redundancy and session failover. It combines ideas from different research areas into a single, resource-efficient and unified architecture. While there have already been a number of contributions on the performance of RSerPool for its main tasks -pool management, load distribution and failover handling -the robustness of the protocol framework has not yet been evaluated against intentional attacks. The first goal of this paper is to provide a robustness analysis. In particular, we would like to outline the attack bandwidth necessary for a significant impact on the service. Furthermore, we present and evaluate our countermeasure approach to significantly reduce the impact of attacks

Bottleneck Identification in Cloudified Mobile Networks Based on Distributed Telemetry

Cloudified mobile networks are expected to deliver a multitude of services with reduced capital and operating expenses. A characteristic example is 5G networks serving several slices in parallel. Such mobile networks, therefore, need to ensure that the SLAs of customised end-to-end sliced services are met. This requires monitoring the resource usage and characteristics of data flows at the virtualised network core, as well as tracking the performance of the radio interfaces and UEs. A centralised monitoring architecture can not scale to support millions of UEs though. This paper, proposes a 2-stage distributed telemetry framework in which UEs act as early warning sensors. After UEs flag an anomaly, a ML model is activated, at network controller, to attribute the cause of the anomaly. The framework achieves 85% F1-score in detecting anomalies caused by different bottlenecks, and an overall 89% F1-score in attributing these bottlenecks. This accuracy of our distributed framework is similar to that of a centralised monitoring system, but with no overhead of transmitting UE-based telemetry data to the centralised controller. The study also finds that passive in-band network telemetry has the potential to replace active monitoring and can further reduce the overhead of a network monitoring system

An Efficient Approach for State Sharing in Server Pools

Many Internet services require high availability. That is, downtimes cause loss of money (e.g. electronic shops) or damages of equipment (e.g. control systems for production processes). Server pooling provides a high availability solution using multiple redundant servers. If one server fails, the service is continued by another one. A big challenge for server pooling is efficient state sharing. That is, servers contain states for each client (e.g. user identity or media position). To continue the service in case of a failover, the new server has to know the old server’s state. The goal of this paper is to present an efficient, simple and scalable approach, applicable to a large range of server pooling applications, that provides secure transfer of states by the client itself, using an extended cookie mechanism. Finally, it also provides implementation considerations. Keywords: high availability, server pooling, state sharing, client, server

An efficient approach for state sharing in server pools

Many Internet services require high availability. Server pooling provides a high availability solution using redundant servers. If one server fails, the service is continued by another one. A challenge for server pooling is efficient state sharing: The new server requires the old one’s state to continue service. This paper proposes a simple, efficient and scalable solution, usable for a large subset of applications.

An Overview of the Reliable Server Pooling Architecture

The convergence of classical PSTN and IP networks requires the transport of SS7 signalling over IP. Since SS7 has very strict availability requirements to the signalling components, redundancy is mandatory. The goal of the IETF RSerPool working group is to define a lightweight, flexible and realtime redundancy concept to fulfil the availability requirements of SS7: reliable server pooling (RSerPool). RSerPool is currently under standardization, its functionality and improvement are subject of our research. Our poster presents our RSerPool proof-of-concept implementation and a research oriented, discrete event based simulation model. We provide simulation results showing limitations of the server selection procedures defined in the standards and a way to solve them. These improvements are now going into standardization by the IETF. Furthermore, we present some of our results on efficient algorithms and data structures for pool management. The poster concludes with an outlook on our currently progressing evaluations of service reliablity in failure scenarios