The 7705 SAR-Hm series of routers supports debug commands that enable detailed debug information for various protocols.
Debug output is generally displayed by configuring a log using from debug-trace.
The currently enabled debug can be seen using the show debug command.
A debug configuration does not persist when the router reboots. The admin debug-save command can be used to save the debug configuration. The resulting file can be exec'ed later as needed.
Individual debug commands are described in the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide.