Theoretically both are separated but in actual deployment both the combined. However few references show both as combined entity.
HSS is mainly used for authentication while SPR is used for QoS. Logically different roles but physically both present in same box.
For example it can be used in the HSS mnc.ncc.3gppnetwork.org and in the MME mnc.ncc.3gpp.org. Or must be same mnc.ncc.3gppnetwork.org?
Is it the wish of HSS or MME or UE ?
In what all scenarios, this procedure gets executed ? And why this procedure need to be executed ?
Does Mme also sends Purge(PUR) to HSS before sending delete session request to SGW when MME receives detach request from enodeb side ? It would be great if you give your valuable suggestion ?