eNB sends UE capability inquiry to UE to know the UE capability during attach before sending RRCReconfiguration. UE sends UE Capability information to eNB to tell about
1. ROHC profile supported
2. Supported bands
3. Feature group indicators etc
eNB uses these information for configuring measurement object of different band, measurement events (a5 if supported), activating ROHC profile to UE if required.