ACI with TGW in AWS multi-region setup

[SIMMN]

According to the whitepaper below

https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-741998.html

Quote: 

"...needs Cisco CSR 1000V Series routers in each region for traffic between the on-premises and cloud sites, which is via AWS Transit Gateway and CSR 1000V routers in the infra VPC..."

But in ACI Hybrid MultiCloud guide below

https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/cisco-cloud-aci-hybrid-multicloud-design-guide.html\

Figure 16 and 19 clearly show CSRv or CAT8Kv is not required for every region. Also Quote:

"...If there is no Cisco Cloud Router in the same region, traffic is forwarded to a region where a Cisco Cloud Router resides and then forwarded to the destination public cloud via VXLAN between Cisco Cloud Routers...."

So is this discrepancy due to the ACI release versions? Or this discrepancy is just human error? Which one has the correct information?

[John Cui · Accepted solution]

Hi, 

Thanks for your question.

You're right. Since the White Paper guide not updated from Nov. 2020, you can refer our new Cloud APIC release note. 

It's new feature introduced at Cloud APIC 5.2(1) version. 

Support for communication with an external site from regions without a CSR in AWS

https://www.cisco.com/c/en/us/td/docs/dcn/aci/cloud-apic/5x/release-notes/cisco-cloud-apic-release-notes-521.html 

"Prior to release 5.2(1), for traffic to pass through to an external site, the region where the traffic is passing through must have a CSR deployed. The CSR advertises the CIDRs that are local to that region. If an EPG in a region has a contract with an external site, then that region must have a CSR deployed in order to communicate with that external site."

https://www.cisco.com/c/en/us/td/docs/dcn/aci/cloud-apic/5x/user-guide/aws/cisco-cloud-apic-for-aws-user-guide-52x/m-cloud-apic-policy-model.html#Cisco_Concept.dita_807f7159-e70c-4a3b-be27-e0072842becc 

BTW, there is an Ask-the-Expert (ATX) live session related to ACI for our Customers and Partners to join and learn more on this product. Click here [https://community.cisco.com/t5/data-center-and-cloud-documents/cisco-aci-ask-the-experts-resources/ta-p/4394491] to go to the ATX Resource Page where you can see the schedule for the incoming sessions and also other references that you might find useful.

Thanks,

John

[SIMMN]

Thanks, good information!