Cicso Routers - Logging Considerations

Important Information on Debug Commands [ISDN/Channel Associated Signalling (ISDN/CAS)] - Cisco Systems: "Warning: Excessive debugs to the console port of a router can cause it to hang. This is because the router automatically prioritizes console output ahead of other router functions. Hence if the router is processing a large debug output to the console port, it may hang. Hence, if the debug output is excessive use the vty (telnet) ports or the log buffers to obtain your debugs. More information is provided below.

Note: By default, logging is enabled on the console port. Hence, the console port always processes debug output even if you are actually using some other port or method (such as Aux, vty or buffer) to capture the output. Hence, we recommend that, under normal operating conditions, you have the command no logging console enabled at all times and use other methods to capture debugs. In situations where you need to use the console, temporarily turn logging console back on."