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Virtual Machine on UCS Blade Server as SPAN Destination without ERSPAN

SMaz32903
Level 1
Level 1

Hello

Is it possible to receive SPAN traffic on a Sniffer VM on UCS without using ERSPAN ?

Our traffic volume is very high and we dont want to use additonal GRE overhead with ERSPAN.

We are using UCS-X (UCSM Mode), FI 6454.

SPAN POV v1.jpg

Requirement is similar to what's documented here but without ERSPAN -

https://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-b-series-blade-servers/200521-Configure-a-Virtual-Machine-on-a-UCS-Bla.html

1 Reply 1

Kirk J
Cisco Employee
Cisco Employee

The UCSMs running in End Host Mode (which is default) does not run spanning tree.  In order to avoid loops, one of the mechanisms involved, does not allow forwarding unknown unicast (which is what a 'non-GRE tunneled' traffic stream would be).

I think a GRE/ERspan session would be the only way to get your traffic down to a guestVM processing the sniffer traffic.  The ERspan stream is a 'known' unicast destination and is able to successfully be delivered down to GuestVM, just like any regular traffic.

 

Kirk...

 

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