Analyzing Network Performance Using RMON and Ethernet Statistics (Layer 2 & Layer 3)

Table 17-3.Port Mirroring Configuration Parameters (Continued)

Parameter Definition

Piggyback Port Port used to enable bi-directional port mirroring. If no piggyback port is specified, only received traffic from the source port will go to the mirror port. The piggyback port should have the same bandwidth as the source port. Only one port per fabric can be used as a piggyback port. Sampling rates have no effect on transmitted information.

 

Considerations:

 

•

You cannot use a port that has been designated as a piggyback

 

 

port.

 

•

Once a port has been designated as a piggyback port, the link

 

 

light is turned on, even if there is no connection on the selected

 

 

port.

 

•

The piggyback port is displayed in place of the source port in the

 

 

VLAN menu.

 

•

If the source and piggyback ports are at a higher bandwidth than

 

 

the mirror port’s bandwidth, the traffic on the source port may

 

 

exceed the bandwidth that the mirror port can handle.

 

•

The piggyback port will always show that it is using multi-layer

 

 

tagging.

 

•

A spanning tree topology change occurs when you change a

 

 

piggyback port.

 

•

Piggyback ports display in certain views of the Cajun P550

 

 

Switch user interface where you typically expect to find

 

 

information about a source port.

 

 

For example, the VLAN Switch Ports list, which displays the list

 

 

of ports associated with a VLAN, includes the piggyback port but

 

 

not the source port.

 

 

In the Intelligent Multicast Session Search and Static Multicast

 

 

Sessions views, the piggyback port displays in place of the

 

 

source port when piggyback port mirroring is enabled.

 

Note: To mirror outbound traffic only, select a source, mirror, and

 

piggyback port. Set the sampling to disable. Since disabling sampling

 

only applies to inbound traffic, only outbound traffic is received.

 

Sampler Type Selects how often you want the mirror port to receive traffic

 

samples:

 

•

Always - sends all samples.

 

•

Periodic - sends samples at the interval described below.

 

•

Disabled - shuts off traffic samples to the mirror port, but keeps

 

 

the association intact.

 

 

Sampling

Displays the number of packets per second that are served by the

Interval

mirror port.

Note: Sampling only applies to inbound traffic.

17-8

Cajun P550/P220 Switch Operation Guide