When the -trace option is used on the buddy command line, CDRouter will display all protocol related log messages. The -include-proto option can be used to display the protocol family along with the log message.
Log filters can be setup based on the protocol family. A list of all available protocol families is displayed with -protocols option. Use the -hide option to filter out specific protocol families. Also, the -show option can be used to only display specific protocol messages.
BuddyWeb users will find these same options in the 'Advanced' tab under 'Log Files'.
To filter out ARP messages:
# buddy -trace -hide ARP -include-proto
To show only SIP and UDP related messages:
# buddy -trace -show SIP,UDP
Please also see this Knowledge Article for more information: How to I adjust the log output level?