Spoke in one-arm concentrator mode ?

[Haixiang]

Hi, I have a few questions about one-arm concentrator mode & Hub and spoke & BGP but couldn't find the answers after reading all the docs I could find. 

1.Can I deploy the branch MX as a spoke while setting it at one-arm concentrator mode ?

2.In this doc, https://documentation.meraki.com/MX/Networks_and_Routing/BGP

it says that  A one-armed VPN concentrator will learn routes advertised to it by other AutoVPN peers and re-advertise these IBGP learned routes to EBGP peers. But in Scenario 3: Datacenter Redundancy (DC-DC Failover), it seems that two one-armed concentrator MXs are not learning routes from each other.

So MXs in one-armed concentrator mode will not be AutoVPN peers or iBGP peers?

3.In the same scenario, Will the routes which VPN Spoke MX learned from One-armed Concentrator MX, be treated as AutoVPN Routes or BGP learned Routes?

Thanks in advance!

[DarrenOC]

Hi Lemist, you may have read this document already but a one-armed concentrator is typically deployed at the DC with the Branch sites auto-vpn'ing back to it:

https://documentation.meraki.com/MX/Deployment_Guides/VPN_Concentrator_Deployment_Guide

Does the third and fourth bullet point answer your query?  It learns its route via autovpn peers and advertise to EBGP peers and vice versa.

Route Advertisement Behavior

Routes are advertised to EBGP and IBGP peers in the following conditions:

• A VPN spoke will advertise all of it's VLANs or static routes that are allowed to participate in the VPN through IBGP to its configured hub.
• A VPN spoke will learn routes advertised to it by other AutoVPN peers.
• A one-armed VPN concentrator will learn routes advertised to it by other AutoVPN peers and re-advertise these IBGP learned routes to EBGP peers
• A one-armed VPN concentrator will learn routes advertised to it by its EBGP peers and re-advertise these EBGP learned routes to other AutoVPN peers via IBGP
• A one-armed VPN concentrator will advertise local networks which are not directly connected and are configured on the site-to-site VPN settings page via IBGP

[PhilipDAth]

>1.Can I deploy the branch MX as a spoke while setting it at one-arm concentrator mode ?

I just tried this - it works.

>seems that two one-armed concentrator MXs are not learning routes from each other.

They only talk about the BGP routes that are learned.  Once learned via BGP they go into AutoVPN.  The other should see those routes through the AutoVPN system.

This also answers you last question.