* trigger re-establshemnt on DU: reset RLC counters on DRB 1
for OAI UE, since SRB 1 does not work for lack of periodic
measurements reports
* how is the re-establishment triggered?
* a transmission on DRB 1 occurs
* detection of a mismatch of RLC counters at the UE side
* max number of RLC retransmissions reached
* RLF detection
* verify re-establishment on CU: we ping the core from the UE; this
sends packets on DRB, and because the sequence number mismatches, will
trigger a reestablishment. We accept in the ping that a couple of
packets might be lost; after ping is over, reestablishment must be
done as well (else the ping will already fail).