RSPAN Configuration - Multiple Intermediary Switches

[Outdoor Adventurer]

Hello Cisco Community, 

I have a brief question regarding the setup of RSPAN via multiple intermediary switches. I am familiar with setting up an RSPAN session between (2) switches, however, when there is a switch in the middle of those two switches - how do I configure the source and destination? I read that is cannot be the same (MONITOR SESSION 1 SOURCE REMOTE VLAN 99 | MONITOR SESSION 1 DESTINATION REMOTE VLAN 99) when using the middle switch as a pass-thru. 

Switch 1

monitor session 1 source vlan 10

monitor session 1 source vlan 20

monitor session 1 destination remote vlan 99

Switch 2 (Intermediary Switch)

** Not sure

Switch 3

monitor session 1 source remote vlan 99

monitor session 1 destination interface fa0/10

Any and all help would be greatly appreciated!

[balaji.bandi]

if layer2 and you have control in the middle of the switch you need configure. or if you like to do over layer3 consider erspan

example :

https://community.cisco.com/t5/networking-knowledge-base/understanding-span-rspan-and-erspan/ta-p/3144951

[Spooster IT Services]

Hi Outdoor Adventurer , 

You need to create Vlan 99  as remote span Vlan on  SW2 .

# vlan 99
# remote-span
Note : On all the intermediate switches the span vlan should be created .

[Georg Pauwen]

Hello,

since I tested this in a lab setup, I might as well post the entire config:

Switch 1
Switch1(config)#monitor session 1 source vlan 10
Switch1(config)#monitor session 1 source vlan 20
Switch1(config)#monitor session 1 destination remote vlan 99
Switch1(config)# vlan 99
Switch1(config-vlan)# remote-span
Switch1(config-vlan)# end

Switch 2
Switch2(config)# vlan 99
Switch2(config-vlan)# remote-span
Switch2(config-vlan)# end

Switch 3
Switch3(config)#monitor session 1 source remote vlan 99
Switch3(config)#monitor session 1 destination interface fa0/10
Switch3(config)# vlan 99
Switch3(config-vlan)# remote-span
Switch3(config-vlan)# end

[Outdoor Adventurer]

I found your solution very helpful. Looking at your configuration, it looks like the intermediary switch only needs the RSPAN VLAN configured. Logically, will the mirrored traffic traverse the RSPAN VLAN until it hits switch with a destination port specified?

If the three switches in question were logically connected to form a triangle in Packet Tracer, I am assuming that all of the switches will be configured with the source VLANs to mirror specified with the collector switch having a destination port specified? Essentially, I need to send all of the traffic for vlans 10 and 20 to switch 3 which will have a collection server sitting off of FA0/10

For example,

Switch 1
Switch1(config)#monitor session 1 source vlan 10
Switch1(config)#monitor session 1 source vlan 20
Switch1(config)#monitor session 1 destination remote vlan 99
Switch1(config)# vlan 99
Switch1(config-vlan)# remote-span
Switch1(config-vlan)# end

Switch 2
Switch1(config)#monitor session 1 source vlan 10
Switch1(config)#monitor session 1 source vlan 20
Switch1(config)#monitor session 1 destination remote vlan 99
Switch1(config)# vlan 99
Switch1(config-vlan)# remote-span
Switch1(config-vlan)# end

Switch 3
Switch3(config)#monitor session 1 source remote vlan 99
Switch3(config)#monitor session 1 destination interface fa0/10
Switch3(config)# vlan 99
Switch3(config-vlan)# remote-span
Switch3(config-vlan)# end