UE Specific DRX ia informed to MME by Attach/ TAU/ RAU request message.(It is not a command but only a suggestion)
I don't know about other network but in LTE ,UE can only request or suggest to the Network. It is the network who decides what to be done. This is why Default Paging DRX given by MME overrides this.
So It is same as Paging DRX i.e Default Paging DRX.