The rise of new applications, such as interactive remote presence, online gaming, and video-assisted remote control of industrial machinery, necessitates enhanced requirements in terms of throughput and delay stability. Many efforts have been made to address these needs, with Deterministic Networking (DetNet) being one such initiative. DetNet aims to guarantee delivery with low latency and minimal jitter, ensuring high reliability and performance for time-sensitive applications. However, DetNet applicability in real-world scenarios is limited due to the need of a lower-layer protocol supporting resource reservation procedures (e.g., MPLS), and the lack of publicly available implementations. In this work, we present SRv6 Live-Live, an easy-to-deploy and highly scalable implementation of DetNet functions using the Segment Routing over IPv6 (SRv6) model. The SRv6 Live-Live behavior replicates packets of a selected flow across multiple paths at the ingress of the SRv6 domain and drops redundant replicas at the egress. After discussing insights about the paths’ selection strategy, we provide a SRv6 Live-Live implementation for programmable data planes using P4. We also propose the use of SRv6 Live-Live for best path selection at line rate, in SD-WAN scenarios. The main results obtained in the extensive performance evaluation are that SRv6 Live-Live preserves the throughput in case of congestion and reduces the tail end-to-end delay with a marginal impact on best-effort flows.

Traditional wisdom suggests maintaining minimal occupancy in the port queues of network devices to prevent packet delays or drops en route to their destination. In this paper, however, we explore the unconventional idea of deliberately congesting the queues of a network device to enhance the performance of a Network Function (NF) deployment. The key intuition behind this approach is to utilize the existing memory available in the switch queues to store packet payloads while their headers are processed on an external NF processor. We present two techniques for congesting a port on a switch: i) self-clocking packet recirculation, which recirculates packets within the switch to automatically achieve the correct queuing delay, and ii) a proportional controller using multicast forwarding, which adjusts the rate of packet forwarding based on the level of congestion. We evaluate our approaches both in simulations and a prototype.

The network programming model of the Segment Routing (SRv6) architecture offers the possibility to define new functions aiming at improving the network performance. In this paper we introduce SRv6 Live-Live, a new behavior for the SRv6 data plane. SRv6 Live-Live is based on two primitives: i) traffic duplication, performed at the ingress node, and ii) the traffic de-duplication, executed at the egress node. The proposed behavior is suitable for the service provisioning of traffic flows having stringent requirements in terms of reliability, low delay and high throughput. Our preliminary performance evaluation, conducted in an emulated environment and realized by using a prototype implementation based on P4, shows that SRv6 Live-Live enhances the performance of the selected traffic flows in challenging network scenarios, characterized by high level of packet corruption/loss and large values of bandwidth-delay products.

Datacenters are a critical part of the Internet infrastructure as they guarantee efficient deployment of a wide range of services. Since a considerable amount of datacenter failures is caused by software bugs and configuration errors, the management and testing of these networks is a crucial task. In this field, emulation-based digital twins have proven their effectiveness. To faithfully emulate the typical three layers hierarchy, composed of physical servers, virtual machines, and containers, the support for nested virtualization is a fundamental requirement. Further, the emulation of hyper-scale datacenters needs to leverage on horizontal scaling over a cluster of nodes. Existing container-based proposals do not meet both requirements. On the contrary, existing VM-based proposals meet such requirements, but they need complex configurations and high resource demands. We propose a container-based framework to faithfully emulate datacenters. This is a fundamental building block for designing datacenter digital twins, that would allow testing of real software implementations in a lightweight, scalable, and easily configurable environment.

Several data centers adopt fat-tree topologies, where high bisection bandwidth is achieved by interconnecting commodity hardware and by using specific routing solutions. These solutions, which include protocol implementations and configurations, are difficult to evaluate and test both for the density of fat-trees and for the complexity of the protocols. Also, since most issues show up only when a fault happens, it is unfeasible to perform such tests in a production environment. Additionally, the lack of standard testing procedures motivates an effort in developing solutions for such a critical task. In this paper, we propose a methodology devised for testing fat-tree routing protocol implementations. It adopts a wall-clock independent method to establish metrics, which permits normalizing the results of different routing protocol implementations independently from the execution environment. The methodology is implemented by Sibyl, a software framework developed to perform repeatable tests on arbitrary fat-tree topologies automatically. Sibyl also provides a set of tools to analyze the results and investigate implementation behaviors. We evaluate the methodology and Sibyl in three use cases. Such use cases witness a wide spectrum of situations where Sibyl is effective for analyzing, comparing, developing, and debugging routing protocol implementations.

We introduce an ETSI NFV compliant, scalable, and distributed architecture, called Megalos, that supports the implementation of virtual network scenarios consisting of virtual devices (VNFs) where each VNF may have several L2 interfaces assigned to virtual LANs. We rely on Docker containers to realize VNFs and we leverage Kubernetes for the management of the nodes of a distributed cluster. Our architecture guarantees the segregation of each virtual LAN traffic from the traffic of other LANs, from the cluster traffic, and from Internet traffic. Also, a packet is only sent to the cluster node containing the recipient VNF. The allocation of the VNFs to the nodes of the cluster is performed by Megalos Scheduler, taking into account the network topology in order to reduce the traffic among nodes. We produce an example application where we emulate a large network scenario, with thousands of VNFs and LANs, on a small cluster of 50 nodes. Finally, we experimentally show the scalability potential of Megalos by measuring the overhead of the distributed environment and of its signaling protocols.

In computer networks, tests to ensure the correct behaviour of network equipment or protocols are often required. Because of the high cost of physical hardware, these tests are always performed in a virtual environment. Kathará is a network emulation system which accurately reproduces the behaviour of a real system. It can exploit several virtualization technologies leveraging on its modularity. Lately, Kathará has been rewritten to overcome some implementation limitations and performance issues. This paper presents the Kathará model and its new architecture, demonstrating its value, comparing its scalability and performance with Netkit (another state-of-the-art tool for network emulation) and with the previous version of Kathará.