Users Guide

Switch Feature Overview 89
Port Mirroring
Port mirroring mirrors network traffic by forwarding copies of incoming and
outgoing packets from multiple source ports to a monitoring port. Source
ports may be VLANs, Ethernet interfaces, port-channels, or the CPU port.
The switch also supports flow-based mirroring, which allows copying certain
types of traffic to a single destination port using an ACL. This provides
flexibility—instead of mirroring all ingress or egress traffic on a port the
switch can mirror a subset of that traffic. The switch can be configured to
mirror flows based on certain kinds of Layer-2, Layer-3, and Layer-4
information.
Destination (probe) ports must be connected to a passive monitoring device.
Traffic sent from the probe into the switch probe port is dropped. Mirrored
traffic sent to the probe device will contain control plane traffic such as
spanning-tree, LLDP, DHCP, etc.
Dell EMC Networking N-Series switches support RSPAN destinations where
traffic can be tunneled across the operational network. Mirrored traffic is
flooded in the RSPAN VLAN from the source(s) to the destination(s) across
any intermediate switches. This allows the administrator flexibility in
connecting destination (probe) ports to the RSPAN. RSPAN does not support
configuration of the CPU port as a source.
For information about configuring port mirroring, see "Monitoring Switch
Traffic" on page 563.
Static and Dynamic MAC Address Tables
Static entries can be added to the switch’s MAC address table and the aging
time can be configured for entries in the dynamic MAC address table. Entries
can also be searched in the dynamic table based on several different criteria.
For information about viewing and managing the MAC address table, see
"MAC Addressing and Forwarding" on page 1117.
Link Layer Discovery Protocol (LLDP)
The IEEE 802.1AB defined standard, Link Layer Discovery Protocol (LLDP),
allows the switch to advertise major capabilities and physical descriptions.
This information can be used to help identify system topology and detect bad
configurations on the LAN.