FINDING · EVALUATION

PushProxy with N=100 parallel push receivers achieves a median 10 MB download time of 16.46s (~4.86 Mbps) without exceeding FCM's 5,000 messages/hour per-deviceToken rate limit, compared to 2.70s for Shadowsocks and 9.68s for OpenVPN (UDP). This throughput significantly exceeds other service-tunneling systems: dnstt (1.5 Mbps) and CensorSpoofer (64 Kbps).

From 2023-xue-use — The Use of Push Notification in Censorship Circumvention · §5.2, Figure 6 · 2023 · Free and Open Communications on the Internet

Implications

Push-notification-based transports must multiplex across N distinct deviceTokens in round-robin to stay under per-token rate limits while scaling bandwidth; N=100 yields usable browsing performance at ~4.86 Mbps.
Service-tunneling designs should prefer providers with higher inherent bandwidth ceilings (FCM at 5,000 msg/hr × 4 KiB ≈ 40 kbps single-token, but parallelizable) over VoIP or DNS channels.