Constructing a low-Earth orbit (LEO) satellite net- work is both capital-intensive and time-consuming. To accelerate deployment and reduce costs, inter-constellation sharing, where multiple satellite network operators (SNOs) share their satellite constellations to build LEO networks collaboratively, has emerged as a promising direction. However, the inherent dynamics of LEO satellites inevitably lead to frequent handovers between terrestrial users and core networks operated by different SNOs, posing significant challenges to network continuity and stability.

This paper presents SATITCH, a new framework that mitigates the adverse effects of inter-SNO handovers and facilitates seamless LEO constellation collaboration. The key idea behind SATITCH is to decouple access satellites from individual SNOs’ core networks, enabling flexible association between shared satellite access points and multiple core networks. This design choice allows terrestrial users to remain connected to their original SNOs as much as possible. Concretely, SATITCH incorporates a flexible, dynamic scheduling algorithm for space-ground connections that aims to minimize inter-SNO handovers experienced by terrestrial users. Further, SATITCH adopts a proactive handover optimization to alleviate the impacts of inevitable interruptions. Our evaluation based on real-world constellation data demonstrates that SATITCH can reduce up to 99.87% flow-level disruption time as compared to existing approaches and ensure smooth real-time video playback.

@INPROCEEDINGS{Lai2605:Seamless,
   AUTHOR="Zeqi Lai and Yunan Hou and Boxuan Hu and Qian Wu and Jun Liu and Rui Chen",
   TITLE="Seamless {Inter-Constellation} Sharing via {Handover-Aware} {Space-Ground} Association",
   BOOKTITLE="IEEE INFOCOM 2026 - IEEE Conference on Computer Communications (INFOCOM 2026)"
}

In datacenters, lossless network is very attractive as it can achieve ultra-low latency. In commodity Ethernet, lossless forwarding is achieved by hop-by-hop Priority-based Flow Control (PFC). To avoid buffer overflow, PFC-enabled switches need to reserve some buffer as headroom, absorbing in-flight packets during the delay for back-pressure messages to take effect. However, with the growing link speed in production networks, the buffer becomes increasingly insufficient, and the headroom can occupy a considerable fraction of buffer. As a result, the remaining buffer for absorbing normal traffic bursts is significantly squeezed, leading to frequent PFC messages that degrade the network performance. Worse yet, we find that the current static and queue-independent headroom allocation scheme is quite inefficient, resulting in significant buffer wastage.

In light of this, we propose Dynamic and Shared Headroom allocation scheme (DSH), which dynamically allocates headroom to congested queues and enables sharing of allocated headroom among different queues. To achieve this, DSH first introduces port-level flow control, which performs flow control at the granularity of individual ports, guaranteeing lossless forwarding with a small fraction of per-port headroom. With this lossless guarantee, the switch is liberated for dynamic headroom adjustment. DSH dynamically allocates per-queue headroom based on the congestion status of each queue. Meanwhile, DSH preserves the queue- level flow control to protect the non-congested queues from being paused by congested queues, ensuring performance isolation on buffer sharing. Extensive experiments and simulations show that DSH can absorb 14× more bursts without triggering PFC messages and reduce the flow completion time by up to ∼31%.

@article{shan2025efficient,
   title={Efficient Headroom Allocation With Two-Level Flow Control for Lossless Datacenter Networks},
   author={Shan, Danfeng and Ma, Jinchao and Li, Yunguang and Hu, Boxuan
                 and Zhang, Tong and Tang, Yazhe and Li, Hao and Wang, Jinyu and Zhang, Peng},
   journal={IEEE Transactions on Networking},
   year={2025},
   publisher={IEEE}
}