[jdev] rfc3920 document: use of TLS

[Chen, Hao]

Hi, 

In the rfc3920 document (XMPP: Core), section 5.2 Narrative, step 5
states that: "The receiving entity MUST reply with either a <proceed/>
element or a <failure/> element..."

My question is upon what conditions the receiving entity replies with
a <proceed/> and upon what conditions it replies with a <failure/>?

Thanks,
-- 
Chen, Hao