PREAMBLE and IMRECEIVING for Improved Large Message Handling in libp2p GossipSub
Muhammad Umar Farooq, Daniel Kaiser
TL;DR
The paper analyzes large-message handling in GossipSub and shows that ignoring message size in forwarding and IWANT decisions causes high bandwidth use and slow dissemination. It introduces PREAMBLE, IMRECEIVING, IWANT improvements, and a reduced-forwarding strategy, all activated for large messages exceeding a threshold, and validates them with the shadow simulator. The results demonstrate substantial improvements, including up to 61% bandwidth reduction and up to 35% latency reduction for large messages, along with reduced duplicates. A GossipSub v1.4 prototype combining these techniques outperforms prior versions, offering practical gains for scaling pub/sub in libp2p networks. Future work includes assessing robustness under adversarial conditions and evaluating on broader test networks such as Ethereum testnets.
Abstract
Large message transmissions in libp2p GossipSub lead to longer than expected network-wide message dissemination times and very high bandwidth utilization. This article identifies key issues responsible for this behavior and proposes modifications to the protocol for transmitting large messages. These modifications preserve the GossipSub resilience and fit well into the current algorithm. The proposed changes are rigorously evaluated for performance using the shadow simulator. Results reveal that the suggested changes reduce bandwidth utilization by up to 61% and message dissemination time by up to 35% under different traffic conditions.
