This section describes mirroring configuration guidelines and caveats.
Multiple mirroring service IDs (mirror destinations) may be created within a single system.
A mirrored source can only have one destination.
The destination mirroring service IDs and service parameters are persistent between router reboots and are included in the configuration saves.
Mirror source criteria configuration (defined in debug>mirror-source) is not preserved in a configuration save (admin save). Debug mirror source configuration can be saved using admin>debug-save.
Physical layer problems such as collisions and jabbers are not mirrored. Typically, only complete packets are mirrored.
When starting or shutting down mirroring on mirror destinations, the following must be considered.
The default state for a mirror destination service ID is shutdown. You must issue a no shutdown command to enable the feature.
When a mirror destination service ID is shut down, mirrored packets associated with the service ID are not accepted from its mirror source or remote source. The associated mirror source is put into an operationally down mode. Mirrored packets are not transmitted out the SAP or SDP. Each mirrored packet is silently discarded. If the mirror destination is a SAP, the SAP’s discard counters are incremented.
Issuing the shutdown command causes the mirror destination service or its mirror source to be put into an administratively down state. Mirror destination service IDs must be shut down first in order to delete a service ID, SAP, or SDP association from the system.
When starting or shutting down mirroring on mirror sources, the following must be considered.
The default state for a mirror source for a given mirror destination service ID is no shutdown. You must enter a shutdown command to deactivate (disable) mirroring from that mirror source.
Mirror sources do not need to be shut down to remove them from the system. When a mirror source is shut down, mirroring is terminated for all sources defined locally for the mirror destination service ID.