Studium vlastností XGS-PON při různých scénářích zatížení sítě

Abstract

This bachelor thesis studies the properties of the XGS-PON access network defined by ITU-T Recommendation G.9807.1 under different network load scenarios. The theoretical part covers the history and evolution of passive optical networks, the topology and communication principle of XGS-PON, the PMD and TC layers of its protocol stack, the dynamic bandwidth assignment (DBA) mechanism, and the factors affecting achievable throughput, including a theoretical derivation of its upper bound. In the practical part, a complete laboratory infrastructure was built around a Huawei MA5800-X7 OLT, two types of ONT units, and a passive distribution network consisting of 10 km of G.652.D fibre with 1:4 and 1:8 optical splitters. A containerised monitoring stack comprising Telegraf, InfluxDB, and Grafana was deployed for independent telemetry collection via SNMPv3 polling. The physical-layer parameters were verified by OTDR measurement, chromatic dispersion, polarization mode dispersion and direct insertion-loss measurement of the optical splitters (OLTS). Quality of service was subsequently tested using three independent methodologies: standardised TCP throughput testing per RFC 6349, SLA parameter verification using the EtherSAM methodology (ITU-T Y.1564), and transport-layer performance testing with iPerf3 under single, concurrent and cross-traffic scenarios with two ONT units. The measurements showed that the network reaches 98.6-99.5 % of the maximum theoretical throughput and revealed two limitations stemming from the internal architecture of the ONT units, which are quantified and analysed in this work.