Proxy and requests queue

[AemNet]

Hi everybody
  I've a question about the management of the queue in freeradius 2.1.12.
Let's assume my server are used for local authentication for the realm 
mydomanin.org and proxy the request for the realm remote.org (a pool 
with a single home server). Let's assume also that max_servers and 
max_spare_server are sets correctly.
What happens if the home server for the proxy takes too long to respond? 
The requests for the local side are ignored or have their own queue? And 
if my proxy are used for different realm (remote1.org, remote2.org 
etc...) all with their own single home_server what happens if a remote 
home server takes too long to respond?
To make a long story short it's possible that a problem on a remote home 
server (that receives a huge number of requests) blocks the requests for 
my local server?

Thanks

I know this can be a stupid question but I didn't find an answer in the 
wiki or in the docs (probably I've searched in the wrong place or the 
wrong terms sorry)

PS: sorry for my English