Dell PowerConnect 8100 User's Configuration Guide - Page 360

The packet that is copied to the destination port is in the same format as the original packet on the wire. This means that if the mirror is copying a received packet, the copied packet is VLAN tagged or untagged as it was received on the source port. If the mirror is copying a transmitted packet, the copied packet is VLAN tagged or untagged as it is being transmitted on the source port. After you configure the port mirroring session, you can enable or disable the administrative mode of the session to start or stop the probe port from receiving mirrored traffic. Why is Traffic Monitoring Needed? Monitoring the traffic that the switch handles, as well as monitoring all traffic in the network, can help provide information about network performance and utilization. This information can be useful in network planning and resource allocation. Information about traffic flows can also help troubleshoot problems in the network. Default Traffic Monitoring Values The sFlow agent is enabled by default, but sampling and polling are disabled on all ports. Additionally, no sFlow receivers (collectors) are configured. Table 16-1 contains additional default values for the sFlow feature. Table 16-1. sFlow Defaults Parameter Receiver timeout for sampling Receiver port Receiver Maximum Datagram Size Maximum header size Default Value 0 6343 1400 bytes 128 bytes RMON is enabled by default, but no RMON alarms, events, or history statistic groups are configured. Port mirroring is disabled, and no ports are configured as source or destination ports. After you configure a port mirroring session, the administrative mode is disabled until you explicitly enable it. 360 Monitoring Switch Traffic