ERSPAN destination type - Nexus 9372

[Dominique Demore]

Hi Everyone,

As part of a migration from a 6500 chassis to a new Nexus deployment, I'm trying to replicate the following configuration for a RSPAN port. Currently, the port of the 6500 is configured as a destination RSPAN. The source port will remaining on the existing remote switch. 

In reading the documentation I've found a number of documents which provide details on creating a Nexus source with an IOS destination, but nothing of the reverse in the ERSPAN method. Would anyone have either a known work around to have a destination ERSPAN port configured on a 9372, or know if I configured the port as a SPAN on the NEXUS with the RSPAN vlan, if that would work.

Does anyone know if/when ERSPAN-destination type will be supported in NX-OS?

Thanks.

--Dominique

[Manish Gogna]

Hi Dominique,

As per the Nexus 9K NX-OS System Management config guide:

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/6-x/system_management/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_System_Management_Configuration_Guide/sm_erspan.html#concept_4BFA95D5237E45FE85F4EADA557B225B

Guidelines and Limitations for ERSPAN

ERSPAN has the following configuration guidelines and limitations:

• For ERSPAN session limits, see the Cisco Nexus 9000 Series NX-OS Verified Scalability Guide.

• The number of ERSPAN sessions per line card reduces to two if the same interface is configured as a bidirectional source in more than one session.

• A single forwarding engine instance supports four ERSPAN sessions. For Cisco Nexus 9300 Series switches, if the first three sessions have bidirectional sources, the fourth session has hardware resources only for Rx sources. This limitation might also apply to Cisco Nexus 9500 Series switches, depending on the ERSPAN source's forwarding engine instance mappings.

• Only ERSPAN source sessions are supported. Destination sessions are not supported.

Manish

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[dgarnsey]

I have the same question - when will ERSPAN destination be supported on the N9K? Is it on the roadmap?

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@Manish Gogna wrote:

Hi Dominique,

As per the Nexus 9K NX-OS System Management config guide:

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/6-x/system_management/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_System_Management_Configuration_Guide/sm_erspan.html#concept_4BFA95D5237E45FE85F4EADA557B225B

Guidelines and Limitations for ERSPAN

ERSPAN has the following configuration guidelines and limitations:

• For ERSPAN session limits, see the Cisco Nexus 9000 Series NX-OS Verified Scalability Guide.

• The number of ERSPAN sessions per line card reduces to two if the same interface is configured as a bidirectional source in more than one session.

• A single forwarding engine instance supports four ERSPAN sessions. For Cisco Nexus 9300 Series switches, if the first three sessions have bidirectional sources, the fourth session has hardware resources only for Rx sources. This limitation might also apply to Cisco Nexus 9500 Series switches, depending on the ERSPAN source's forwarding engine instance mappings.

• Only ERSPAN source sessions are supported. Destination sessions are not supported.

Manish

- Do rate helpful posts -

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