ACI Routing Control - DR

[MSJ1]

Consider that L3Out Link is not yet in Place between PRD Tnt to ISN RTR ( at left side of the Diagram ).
I am evaluating the situation if I bring the L3Out Link between DR PRD Tenant to ISN RTR.

At DR Site PRD Tnt through L3Out it will receive Route for Subnets from Active Site normally if we configure
0.0.0.0/0 as part of the traffic classification, on the other hand same subnets ( Active Site Subnets ) are configured
at DR PRD Tnt ( Left side of the image ) , since there will be a routing conflict.

How at ACI we can restrict not to receive routes at DR PRD Tnt from Active Site ( Right Side of the Diagram ) which will come
through ISN Router on the Diagram ? At DR Prd Tenant it should only receive routes from DR Tier-0 Tenant through "ISN Router".

[AshSe]

Hello @MSJ1 

I understand that you are concerned about a routing conflict in your DR PRD Tenant when you bring up the L3Out connection to the ISN Router, as it will start receiving routes from the Active site that overlap with subnets already configured within the DR PRD Tenant. You want to ensure the DR PRD Tenant only receives routes from the DR Tier-0 Tenant (via the ISN Router) and not from the Active site via the new L3Out.

Below is the suggestion:

Route Filtering on the L3Out Connection:

• Prefix-Based Filtering (Preferred): This is the most precise and recommended approach. You'll configure a route-map or prefix-list on the L3Out connection in the DR PRD Tenant to filter out the specific subnets originating from the Active site.

Hope This Helps!!!

AshSe

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[jackobjasson2377]

In ACI you typically solve this with route control on the L3Out using route-maps / import policies (or contract-based filtering) so the DR tenant only accepts prefixes from the DR Tier-0 path and explicitly denies/filters anything learned via the ISN from the active site. Careful route design is key here, just like using a calculadora de horas helps keep planning structured and avoids conflicts in tracking time and resources.