: Diameter OriginHost and OriginRealm values

Hello,

i could not find the answer to my question in rfc 3588 or in the mail 
archive, so here it is:

does the Origin-Host value has to include the Origin-Realm ?

for example is the following correct ?
Origin-Host : myclient
Origin-Realm : acme.com

or does it have to be :
Origin-Host : myclient.acme.com
Origin-Realm : acme.com

all the examples in rfc 3588 seem to favour the second solution.
but is it normative ?

Thank you and best regards
Gerard.