ZeroMQ: The Design of Messaging Middleware - http://www.drdobbs.com/article/print?articleId=240165684&siteSectionName=architecture-and-design

When NOT to use a message queue - http://techblog.bozho.net/?p=1455

现代IM系统中的消息系统架构 - 架构篇 - https://yq.aliyun.com/articles/698301