This article explains the fundamental message exchange patterns—including publish‑subscribe, fan‑out, unidirectional and bidirectional streaming—as well as routing models such as unicast, broadcast, multicast, and anycast, illustrating each with common technology examples.
Baidu’s live‑streaming message service evolved from a basic group‑chat model to a scalable multicast architecture that delivers up to a million concurrent users per room with sub‑second latency, using message aggregation, compression, and priority channels to manage QPS, bandwidth, and reliable gift delivery.
This article analyzes Baidu's live‑stream messaging system, compares it with ordinary group chat, identifies scalability challenges, proposes a multicast (mcast) architecture, evaluates performance, bandwidth, and client impact, and outlines further enhancements such as historical and gift messages.
This article explains the four primary IP transmission methods—unicast, multicast, broadcast, and anycast—detailing their address ranges, typical use cases, and how they differ in delivering data to one, many, or a selected recipient within a network.
The article explains that in ReactiveCocoa cold signals are plain RACSignal instances that start their work per subscriber, while hot signals are RACSubject (or subclasses) that broadcast a single execution to all observers, and demonstrates converting cold to hot using subjects, multicast operators, and replay helpers such as replayLazily to share network requests.
The article breaks down RACSignal’s three‑step subscription flow, then explains how multicast and replay operators—built on RACSubject and RACReplaySubject—share a single source, buffer values, and ensure side‑effects like network requests execute only once regardless of how many subscribers attach.
