The download manager is a system service that handles long-running HTTP downloads. The download manager will conduct the download in the background, taking care of HTTP interactions and retrying downloads after failures or across connectivity changes and system reboots.

After the connection is lost while downloading a particular file the download manager give 2.5 min window where it retries to find the network after every 30 sec for 5 times.After which if it dosen't find the network it will remove the downloaded files cache i.e resumable downloading after 2.5 min is not possible while using this