Cloud-native challenges

Traditional telco systems were not exactly born for today’s cloud-native ecosystem (recommended reading: pet vs. cattle).

  • Elastic Scaling of Real Time Communication Services [ link ]
    Published in IEEE Transactions on Network and Service Management, 2026.
    Máté Nagy; Tamás Lévai; Felicián Németh; Aurojit Panda; Gianni Antichi; Gábor Rétvári

    TL;DR: Kubernetes networking is built on NAT , which replaces the source address of packets in transit. This is particularly problematic for real-time media where users are identified by their source address (IP and port). In this paper we explore how a custom service mesh could work around this limitation. This line of work also gave rise to the popular WebRTC gateway, STUNner, largely thanks to the brilliance of Gábor Rétvari.

  • Industrial-scale Stateless Network Functions [ pdf ]
    Published in: IEEE Cloud, Milan, Italy, 2019.
    Márk Szalay, Máté Nagy, Dániel Géhberger, Zoltán Kiss, Péter Mátray, Felician Németh, Gergely Pongrácz, Gábor Rétvári, László Toka

    TL;DR: High performance (low latency and jitter) is the primary focus when designing telco media servers. Before the cloud era, keeping session state in-process was not a limitation but a feature, with resiliency delegated to hardware. Once these services moved to the cloud, that was no longer an option — the software itself had to handle failures gracefully. Imagine a server handling all live sessions of a small country going down; the inability to call 911 is simply unacceptable. The challenge I received from my former manager was to come up with a practical solution. Thanks to a superfast in-house database and a few enthusiastic colleagues, the solution made it into the product, and this paper and several patents followed.

Information theory

  • R3D3: A Doubly Opportunistic Data Structure for Compressing and Indexing Massive Data [ pdf ]
    Published in: Infocommunications Journal, 11:58–66, 2019.
    Máté Nagy, János Tapolcai, Gábor Rétvári

    TL;DR: Succinct data structures let you store data in a compact form while keeping it directly accessible — no need to decompress before querying. R3D3 is a tweak to the popular RRR representation scheme, by leveraging longer block sizes to reduce the size of the index. It didn’t exactly set the world on fire, though 😄

Network optimization for resiliency

Providing resiliency to pure IP networks by altering the topology was a hot topic in the 2010s. If you’re curious about the details, check out the intro of my dissertation. In these papers, we offered different solutions to the problem.

  • Node Virtualization for IP Level Resilience [ pdf ]
    Published in: IEEE/ACM Transactions on Networking, 2018.
    Máté Nagy, János Tapolcai, Gábor Rétvári

  • On the design of resilient IP overlays [ pdf ]
    Published in: Design of Reliable Communication Networks (DRCN), 2014.
    Máté Nagy, János Tapolcai, Gábor Rétvári

  • Optimization methods for improving IP-level fast protection for local Shared Risk Groups with Loop-Free Alternates. [ pdf ]
    Published in Telecommunication Systems, 2014.
    Máté Nagy, János Tapolcai, Gábor Rétvári

Dissertation

For sleepless nights, when nothing else works…