How does Jgroup on UDP become reliable?

In my mind, UDP开发者_如何学运维 is fast but not reliable, and in a lot of places jgroup is based on UDP, is that reliable? I saw a lot of places use jgroup to transfer caching information. Does jgroup have to use TCP to make transition reliable?

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JGroups provides components to implement reliability above UDP, see here for some details,

http://www.jgroups.org/manual/html_single/index.html#d0e5392