6.1.c Implement and troubleshoot logging

6.1.c [i] Local logging, syslog, debug, conditional debug

Cisco router’s or switch’s log messages can be handled in five different ways:

Console logging: By default, the router sends all log messages to its console port. Users that are physically connected to the router console port can view these messages.

Terminal logging: It is similar to console logging, but it displays log messages to the router’s VTY lines instead. This is not enabled by default.

Buffered logging: This type of logging uses router’s RAM for storing log messages. buffer has a fixed size to ensure that the log will not deplete valuable system memory. The router accomplishes this by deleting old messages from the buffer as new messages are added.

Syslog Server logging : The router can use syslog to forward log messages to external syslog servers for storage. This type of logging is not enabled by default.

SNMP trap logging: The router is able to use SNMP traps to send log messages to an external SNMP server.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 5573-5576).  . Kindle Edition.

http://www.cisco.com/c/en/us/support/docs/dial-access/integrated-services-digital-networks-isdn-channel-associated-signaling-cas/10374-debug.html