Shuo Li, Steven Chien, Tianyi Gao, and Michio Honda, University of Edinburgh
Layer 7 load balancers (L7LBs) play an important role in per-request server selection within long-lived connections and transport- or application-layer protocol translation. However, L7LBs introduce substantial CPU and network overhead.
We present XO, which enables an L7LB to offload transport-layer and application request processing to backend servers at request granularity. XO outperforms conventional L7LBs by 27–365% in throughput through efficient utilization of server CPU and network resources. We apply XO to two real-world applications, Ceph and nginx, improving throughput by up to 135% and 300%, respectively.
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author = {Shuo Li and Steven Chien and Tianyi Gao and Michio Honda},
title = {Remote {TCP} Connection Offload and Applications},
booktitle = {23rd USENIX Symposium on Networked Systems Design and Implementation (NSDI 26)},
year = {2026},
isbn = {978-1-939133-54-0},
address = {Renton, WA},
pages = {527--541},
url = {https://www.usenix.org/conference/nsdi26/presentation/li-shuo},
publisher = {USENIX Association},
month = may
}
