547a61d4_tware_Releases_12_4_T____Cisco__Key_or_Nonkey_Field
[Field] IPv4 Destination Mask [Definition] Number of bits in the destination prefix. [Key or Nonkey Field] 
Key
K e y
N o n k e y
Flexible Netflow Configuration Guide, Cisco IOS Release 12.4T - Configuring Cisco IOS Flexible NetFlow with Predefined Records [Cisco IOS Software Releases 12.4 T] - Cisco