Question: During a handover procedure between two NG-RANs at the Xn interface (direct DL data forwarding), how should bits 5-8 of octet 2 in the PDCP PDU Number Extension Header be set?
Option 1: Set to one for indicating sequence continuation
Option 2: Used for encoding additional sequence information
Option 3: Shall be set to zero as they are spare
Option 4: Dependent on the value of the Length field
Explanation: According to handover specifications between two NG-RANs at the Xn interface, bits 5-8 of octet 2 in the PDCP PDU Number Extension Header are spare. As per standard practice for unused bits in protocol headers, they should be set to zero, ensuring compatibility and preventing unforeseen behavior during handover.