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Is an ERSPAN loop possible ?

pHz
Level 1
Level 1

We have two routers (Nexus 9k), router A and router B. Currently, we have one monitoring node connected to router A, and we're running an ERSPAN session from router B to router A to copy traffic of specific vlans (let's say vlan 100). Then router A sends that traffic to the monitoring node.

The thing is that we want to add a new monitoring node, but this time connected to router B. We want to create a new ERSPAN session, now from router A to router B, to copy traffic of the same vlans (vlan 100). 

What I am wondering is whether or not that could create a loop ? i.e., router B receives traffic on vlan 100 and copies it to router A via its ERSPAN session. And then, after receiving this, router A notices that it's vlan 100 so it's going to also copy that traffic back to router B via the new ERSPAN session we configured. Is it possible ? Or would it only be the "true" vlan traffic entering the Nexus devices that get copied by the ERSPAN session ?

I made a quick drawing. Our goal is to create the red ERSPAN session (without bringing down the network).

 

erspan.png

1 Reply 1

balaji.bandi
Hall of Fame
Hall of Fame

i would suggest to use different VLAN on ERPSPAN2

other note, why you looking 2 ERSPAN ?

 

BB

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