When UE is idle and there is DL traffic, the SGW sends Downlink data notification to the MME.
The MME page the Mobile, if this paging fails for any reason (in my case the UE lost the radio) the MME sends downlink data notification failure to the SGW,
What happens if after some time there is more traffic downlink to the EU. Should the SGW send a new downlink data notification to the MME? How long does it wait before sending?