T310, N310, N311 is related to Radio Link Failure and Recovery process as illustrated below. Regarding the detailed meaing of these parameters, refer to the following post at LTE University. It explains better than I would do.
Note 1 : one "Out of Sync Indication" in this diagram means "20 subframes of consecutive PDCCH decoding failure.
Note 2 : one "In Sync Indication" in this diagram means "10 subframes of consecutive PDCCH decoding success.