Cache miss #2

Client A sends a HTTP request, it gets to proxy B, which does not have the relevant document cached, it then sends a ICP request to its siblings (proxy C), and to its parent (proxy A). Proxies A & C does not have the document either, and they do not send a ICP reply, after a set period of time, proxy B has a timeout, and it requests its parent (Proxy A) to retrieve the document. Proxy A send a HTTP request to the destination server, and gets a HTTP reply, he then sends the document in a ICP reply to proxy B, which then sends the relevant document to the client.