Slicing and sampling are available to all mirror destinations:
slicing
Slicing copies a specified packet size of each frame. This is useful to monitor network usage without having to copy the actual data. Slicing enables mirroring larger frames than the destination packet decode equipment can handle. It also allows conservation of mirroring resources by limiting the size of the stream of packet through the router and the core network.
When a mirror slice size is defined, a threshold that truncates a mirrored frame to a specific size is created. For example, if a value of 256 bytes is defined, up to the first 256 bytes of the frame are transmitted to the mirror destination. The original frame is not affected by the truncation. Mirrored frames, most likely, become larger as encapsulations are added when packets are transmitted through the network core or out the mirror destination SAP to the packet or protocol decode equipment. Slice size is not supported by CEM encap-types or IP mirroring.
The transmission of a sliced or non-sliced frame is also dependent on the mirror destination SDP path MTU and the mirror destination SAP physical MTU. Packets that require a larger MTU than the mirroring destination supports are discarded if the defined slice size does not truncate the packet to an acceptable size.
sampling
Mirror sampling rate defines a packet sampling rate for a mirror service. The sampling rate is applicable to all endpoints in the mirror source ingress and egress and supported on FP4-based cards.
This capability can be useful for analytics purposes such as DDoS telemetry to provide a subset of traffic while still maintaining statistical accuracy using packet sampling.
Packet sampling can be configured concurrently with mirror slicing to further limit the amount of traffic sent to the collector.
For endpoints in the mirror source on FP2- and FP3-based cards, all the packets are mirrored without sampling.