Virtualized eNB Latency Limits

In flexible functional split, functions of a virtualized evolved NodeB (eNB) can be disaggregated in distributed computational resources. One of the main constraints for their placement is the latency experienced by the communication between the Virtual Machines (VM) hosting the functions. This paper evaluates experimentally the latency limits for different functional splits providing insights on flexible functional split implementationThis work has been partially funded by the EU H2020 5G-Transformer Project (grant no. 761536

Experimental Demonstration of Impairment-Aware PCE for Multi-Bit-Rate WSONs

In emerging multi-bit-rate wavelength switched optical networks (WSONs), the coexistence of lightpaths operating at different bit-rates and modulation formats (e.g., based on amplitude and phase modulation) induces relevant traffic dependent detrimental effects that need to be considered during impairment-aware routing and wavelength assignment (IA-RWA). The considerable complexity of IA-RWA computation has driven the Internet Engineering Task Force (IETF) to propose specific path computation element (PCE) architectures in support of IA-RWA for WSONs. In this paper, following the IETF indications, we expand two PCE architectures and experimentally evaluate five different PCE architectural solutions, performing either combined or separated impairment estimation and RWA, with on-line and off-line computation of impairment validated paths, and with the possible utilization of a novel PCE Protocol (PCEP) extension. Results in terms of traffic engineering performance, path computation delivery time and amount of exchanged PCEP messages are reported and discussed to highlight the benefits and application scenarios of the considered PCE architectures

Segment routing for effective recovery and multi-domain traffic engineering

Segment routing is an emerging traffic engineering technique relying on Multi-protocol Label-Switched (MPLS) label stacking to steer traffic using the source-routing paradigm. Traffic flows are enforced through a given path by applying a specifically designed stack of labels (i.e., the segment list). Each packet is then forwarded along the shortest path toward the network element represented by the top label. Unlike traditional MPLS networks, segment routing maintains a per-flow state only at the ingress node; no signaling protocol is required to establish new flows or change the routing of active flows. Thus, control plane scalability is greatly improved. Several segment routing use cases have recently been proposed. As an example, it can be effectively used to dynamically steer traffic flows on paths characterized by low latency values. However, this may suffer from some potential issues. Indeed, deployed MPLS equipment typically supports a limited number of stacked labels. Therefore, it is important to define the proper procedures to minimize the required segment list depth. This work is focused on two relevant segment routing use cases: dynamic traffic recovery and traffic engineering in multi-domain networks. Indeed, in both use cases, the utilization of segment routing can significantly simplify the network operation with respect to traditional Internet Protocol (IP)/MPLS procedures. Thus, two original procedures based on segment routing are proposed for the aforementioned use cases. Both procedures are evaluated including a simulative analysis of the segment list depth. Moreover, an experimental demonstration is performed in a multi-layer test bed exploiting a software-defined-networking-based implementation of segment routing

Impact of CoMP VNF Placement on 5G Coordinated Scheduling Performance

To address demanding requirements in terms of expected throughput, latency and scalability, 5G networks will offer high capacity to support huge volumes of traffic generated by heterogeneous services. Dense deployment of small cells can provide a valid solution but are prone to high levels of interference especially at the cell-edge. However, to reduce inter-cell interference and improve cell-edge throughput, a set of techniques known as Coordinated Multipoint (CoMP) has been introduced. Coordinated Scheduling (CS) is a CoMP technique that assigns resources to mobile users to avoid interference between users that are assigned within the same Physical Resource Blocks (PRBs). On the other hand, Software Defined Mobile Networking (SDMN) and Network Function Virtualization (NFV) represent two key technologies to enhance flexibility and efficiency of resource usage within the Radio Access Network (RAN). However, the implementation of CoMP CS techniques on NFV architecture in a dense small cell scenario have not been analyzed yet. In this paper, we propose the joint use of CoMP CS and NFV by studying the implications of different deployment strategies, as constrained by the physical topology of the underlying RAN. The performance of both distributed and centralized CoMP CS are compared in terms of convergence delay and traffic overhead. Guidelines for the optimal design are provided.This work was partially supported by the Italian Government under CIPE resolution no. 135 (December 21, 2012), project INnovating City Planning through Information and Communication Technologies (INCIPICT) and by the EC through the H2020 5G-TRANSFORMER project (Project ID 761536)