Developers widely use actor frameworks to build highly distributed systems. However, modern actor frameworks are limited in their network implementations, with Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) being the main protocols used for network communication. This thesis investigates the use of specialized network protocols to improve the performance of actor frameworks in distributed systems. Message-passing, while commonly based on TCP, needs more performance and security than other protocols; therefore, the focus will be on different low-latency transport protocols that could substitute TCP. This work examines actor communication at the transport layer, considering the constraints of the deployment that often dictate the choice of a transport protocol. We explore how Quick UDP Internet Connections (QUIC), a low-latency transport protocol, affects actor systems performance and reliability by investigating the benefits of replacing TCP with QUIC in Kompact, a component-actor hybrid framework. We provide an overview of other low-latency protocols that fit various actor frameworks and implement QUIC in the networking layer of Kompact. Thereof, we evaluate the performance of QUIC, UDP and TCP in two different scenarios, such as file transfers outside of actor systems and ping-pong latency measurements within Kompact. The results show that glsquic outperforms TCP for larger file transfers outside actor systems, accomplishing higher throughput and faster download times. However, in the Kompact benchmark, QUIC did not outperform TCP due to issues with QUIC’s event loop implementation. The study also highlights the importance of proper synchronization between event loops in distributed systems. The findings suggest that QUIC has the potential to improve performance and reliability in actor systems by reducing latency and enhancing reliability through features such as multiplexing and connection migration. / Utvecklare använder i stor utsträckning actor-ramverk för att bygga väldigt distribuerade system. Moderna actor-ramverk är dock begränsade i sina nätverksimplementationer, med TCP och UDP som de huvudsakliga protokollen för nätverkskommunikation. Denna avhandling undersöker användningen av specialiserade nätverksprotokoll för att förbättra prestandan hos actor-ramverk i distribuerade system. Meddelandehantering, som vanligtvis är baserad på TCP, kräver högre prestanda och säkerhet än andra protokoll. Därför kommer fokus att ligga på olika låg-latens transportprotokoll som kan ersätta TCP. Denna undersökning undersöker actor-kommunikation på transportlagret, med hänsyn till de begränsningar som ofta dikterar valet av transportprotokoll. Vi utforskar hur QUIC, ett låg-latens transportprotokoll, påverkar prestanda och tillförlitlighet i actor-system genom att undersöka fördelarna med att ersätta TCP med QUIC i Kompact, ett komponent-actor hybrid-ramverk. Vi ger en översikt över andra låg-latens protokoll som passar olika actor-ramverk och implementerar QUIC i nätverkslagret av Kompact. Därigenom utvärderar vi prestandan för QUIC, UDP och TCP i två olika scenarier, såsom filöverföringar utanför actor-system och ping-pong-latensmätningar inomKompact. Resultaten visar att QUIC överträffar TCP för större filöverföringar utanför actor-system, uppnår högre genomströmning och snabbare nedladdningstider. Men i Kompact-benchmarken överträffade QUIC inte TCP på grund av problem med QUICs event-loop-implementering. Studien belyser också vikten av korrekt synkronisering mellan event-loops i distribuerade system. Resultaten antyder att QUIC har potential att förbättra prestanda och tillförlitlighet i actor-system genom att minska latens och förbättra tillförlitligheten genom funktioner som multiplexing och anslutningsmigration.

This thesis presents an empirical analysis of the performance of WebTransport and WebSocket using the Socket.IO framework under varying network conditions. The thesis investigates two primary experiments, message round trip time and multiplexing performance, both conducted under three scenarios—perfect network (0% packet loss), moderate network (5% packet loss), and poor network (15% packet loss). The experiments were conducted on a system running Fedora 40 with a 12th Gen Intel Core i5-12600K processor and 16 GB of memory. The findings demonstrate that WebTransport mitigates Head-of-Line (HOL) blocking more effectively than WebSocket, especially in environments with degraded networks. WebTransport (Reliable) provided a significant performance advantage under suboptimal network conditions when measuring message round trip time, while WebTransport (Unreliable) consistently demonstrated slightly lower latency but with some data loss. When multiplexing, WebTransport showed significant performance benefits compared to using WebSocket.

In this thesis the control of ultrafast (10⁻¹³ s) optical pulses used for metrological applications has been investigated. Two different measurement set-ups have been considered, both based around the `pump-probe' technique, where an optical pulse is divided into two parts, one to `pump' or excite a physical system of interest, the other to `probe' or measure the outcome. In both cases the measurement uses electro-optic sampling (EOS), where an electric field is measured by detecting changes in the optical probe pulse polarisation after interaction with the field. In the first study, a method for wavelength metrology in the terahertz (THz) region has been demonstrated by producing an optical pulse shaper and genetic algorithm to control pump pulses and so indirectly influence the THz spectra they generate. In the second study an OPO (optical parametric oscillator) has been developed to provide ultrafast optical pulses for the generation of < 100 fs electrical pulses for metrology using quantum interference control (QUIC). QUIC electrical signals have been demonstrated successfully by charge accumulation measurements and the QUIC electrical pulse temporally measured using EOS, though the low signal levels due to power restrictions mean the QUIC electrical pulse is unsuitable for metrology at this time. Finally, a portable optical pulse measurement device based around frequency-resolved optical gating (FROG) has been designed, built and tested. This has been shown to be capable of retrieving amplitude and phase information in both the temporal and spectral domains for optical pulses as short as 20 fs duration. The ability to characterise shaped pulses also has been demonstrated successfully, with the requirements for full automation identified.

New developments in web transport such as HTTP/2 and first and foremost QUIC promise fewer connections to track as well as shorter connection setup times. These protocols have proven themselves on modern reliable connections with a high bandwidth-delay-product, but how do they perform over cellular connections in rural or crowded areas where the connections are much more unreliable? A lot of new users of the web in todays mobile-first usage scenarios are located on poor connections. A testbench was designed that allowed for web browsing over limited network links in a con- trolled environment. We have compared the network load time of page loading over the protocols QUIC, HTTP/2 and HTTP/1.1 using a variety of different network conditions. We then used these measurements as a basis for suggesting which protocol to use during different conditions. The results show that newer is not always better. QUIC in general works reasonably well under all conditions, while HTTP/1.1 and HTTP/2 trade blows depending on connection conditions, with HTTP/1.1 sometimes outperforming both of the newer protocols.

The goal of the Master thesis on the topic of the Client application of DNS protocol with graphical interface for teaching purposes is to create a program with the features of sending, receiving DNS, MDNS and LLMNR protocols with optional parameters. Additionally, compare the created application with available tools such as Nslookup, Dig and create examples of application for teaching.