We discussed SPANs earlier, but let’s talk about RSPANs for a bit.
Can anyone guess what the “R” means? You guessed it – “Remote”. An RSPAN is a way to get traffic from a SPAN source on one switch to a SPAN destination on another switch that’s connected via a trunk.
The basic premise is that a special VLAN is created on all the switches and allowed to traverse the trunks. You then set up a SPAN session that copies your traffic to this special VLAN. This VLAN then gets the traffic to the other switches through some voodoo magic to be used as source for a SPAN on another switch.