BGP Peering between Private & Public AS

[RS19]

I have the below scenario. I have Cisco router running BGP & want to have BGP peering with the service provider (Using public Interface)

The service provider has provided Public IP Range for peering & also his side Public AS number.

From my side router, I want to use Private AS number to form the BGP peering.

Is this possible ?
Can I form BGP neigh when 1 side is using Private AS & the other side uses Public AS ?

Normally will the service providers allow this communication for BGP peering ?

[Harold Ritter]

Hi @RS19 ,

It is certainly possible from a technical perspective. I imagine you want to run BGP with the service provider for redundancy reasons? At the end of the day, you will need to discuss it with your service provider to find out whether they are willing to support such a configuration.

Regards,

[RS19]

Thanks.
The actual scenario is that I am trying to peer with AWS on Public VIF from my On Prem router.
I have the Public IP Segment assigned by AWS for peering & I know the ASN of AWS which is Public ASN.

At my side, can I use private ASN for the BGP peering. Will AWS allows it ?

[Harold Ritter]

Hi @RS19 ,

I did a quick search and found the following statement.

"For BGP ASN, enter the Border Gateway Protocol Autonomous System Number of your on-premises peer router for the new virtual interface.

For a public virtual interface, the ASN must be private or already on the allow list for the virtual interface.

The valid values are 1-2147483647.

Note that if you do not enter a value, we automatically assign one."

https://docs.aws.amazon.com/directconnect/latest/UserGuide/add-peer-to-vif.html

I would recommend you discuss it with them though.

Regards,

[RS19]

Is there any reference document from Cisco side for SD-WAN how to connect to AWS Public VIF ?

Any sample configuration or any use case design reference document ?

I wanted to know what are the steps and procedures to be configured in Cisco SD-WAN to connect to AWS public vif

[MHM Cisco World]

There is no issue if SP have accept Private ASN.