The -tn and -6tn command line parameters

The -tn parameter specifies the external tracing level for OMPROUTE initialization and IPv4 routing protocols, where n is a supported trace level. The -6tn parameter specifies the external tracing level for IPv6 routing protocols, where n is a supported trace level. The -tn and -6tn traces are intended for customers, testers, service, or developers, and provide information on the operation of the routing application. These options can be used for many purposes, such as debugging a configuration, education on the operation of the routing application, verification of test cases, and so on. The following levels are supported:
1
Informational messages
2
Formatted packet trace

These option levels are cumulative—level 2 includes level 1. For example, -t2 provides formatted packet trace and informational messages.