Backend Development 13 min read

Design and Implementation of the Dandelion Resource Distribution Platform for Dual‑Teacher Classroom

This article describes the challenges of delivering large video lessons and other digital assets to distributed school campuses and explains how the Dandelion release platform uses resumable uploads, cloud OSS, long‑connection messaging, redundancy, and version‑controlled rollout to ensure reliable, low‑latency playback and scalable resource distribution.

TAL Education Technology
TAL Education Technology
TAL Education Technology
Design and Implementation of the Dandelion Resource Distribution Platform for Dual‑Teacher Classroom

Background: The dual‑teacher classroom combines recorded video with on‑site teachers, involving three roles (anchor teacher, main teacher, students). Video lessons are large (1‑3 GB) and need to be uploaded, previewed, reviewed, and delivered to both the R&D demo class and franchise schools.

Challenges: uploading large video files quickly from the R&D center, ensuring smooth playback over unstable external networks at franchise sites, and supporting gray‑release and A/B testing across locations.

Solution – Dandelion Release Platform: three stages of video migration (local data‑center → OSS, then → campus data‑center) and a full‑stack architecture comprising CMDB, version management, release platform, Mercedes Server, Beetle, Talgate, Mercedes Agent, and Cadillac.

Key techniques: use of the tus protocol for resumable uploads, bandwidth testing with dual ISP lines, long‑connection messaging with ACK, timeout‑retransmission and deduplication, timestamp‑based recovery, dual‑server redundancy with LVS, and automatic fallback to external network when the internal network fails.

Resource distribution also supports other asset types (interactive media, app packages, Docker images, etc.) through a unified resource model and release workflow, with version control and city‑/campus‑specific rollout strategies.

Results: the platform enables reliable, low‑latency playback of large video lessons without dependence on external networks, supports over 250 + course videos and 1 000 + interactive resources, and provides robust monitoring and alerting.

cloud storagelarge file handlingdistributed systemversion managementvideo-uploadresource distribution
TAL Education Technology
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TAL Education Technology

TAL Education is a technology-driven education company committed to the mission of 'making education better through love and technology'. The TAL technology team has always been dedicated to educational technology research and innovation. This is the external platform of the TAL technology team, sharing weekly curated technical articles and recruitment information.

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