Encapsulated remote switched port analyzer (ERSPAN) is used to
transport mirrored traffic in an IP network. ERSPAN supports source ports,
source VLANs, and destinations on different switches, which provide remote
monitoring of multiple switches across your network. ERSPAN uses a generic
routing encapsulation (GRE) tunnel to carry traffic between switches.
consists of an ERSPAN source session, routable ERSPAN GRE-encapsulated traffic,
and an ERSPAN destination session. You separately configure ERSPAN source
sessions and destination sessions on different switches.
configure an ERSPAN source session on one switch, you associate a set of source
ports or VLANs with a destination IP address, ERSPAN ID number, and virtual
routing and forwarding (VRF) name. To configure an ERSPAN destination session
on another switch, you associate the destinations with the source IP address,
the ERSPAN ID number, and a VRF name.
ERSPAN source session copies traffic from the source ports or source VLANs and
forwards the traffic using routable GRE-encapsulated packets to the ERSPAN
destination session. The ERSPAN destination session switches the traffic to the