Correct way to discover and provision separate CP nodes in SDA

[Madura Malwatte]

I have two separate ISR 4451's which are meant to be the control plane (CP) nodes in my SDA fabric. They are dual connected directly to the fabric border nodes. Now to discover these CPs it looks like the only way to do it is to manually configure the link from CP to borders as a L3 interface (since lan automation does not work for ISR i.e CP nodes). So I have configured a random /30 subnet between each CP and border and now I am able to discover these. Then what happens when I add these ISR devices to the fabric site as control plane nodes? Does DNAC reconfigure these to give loopbacks and P2P IP addresses from my lan automation pool? I am assuming I need to configure static routing on the CP nodes manually so they can reach all the nodes in the fabric, but what about the fabric nodes, how would they know about the route to the /30 subnet between border and CP to reach the CP? So confused here...

It seems I need to manually configure the CP nodes connectivity and assign L3 links from CP to border nodes? I haven't left any IP space for 4x /30's for dual connecting the CP nodes, so could I steal them from the lan-automation IP pool /21 I have reserved and use for the CP's? Or will this break the fabric?

Also when these ISRs are added to inventory, the device role option doesnt have any choice to select them as control plane:

[Flavio Miranda]

Hi

  Usually we configure a DHCP scope on the Edges  (4451) and static routes inicially. As soon as we plug the 9300 or 9500 which will be part of the fabric, they get IP address and perform de PNP with DNAC. So that DNAC can setup BGP on the Fabric to communicate with Edges.

  At leat one manual intervention is necessary to change cable between Edge and fabric after PNP is complete and device is managablel by DNAC.

[Madura Malwatte]

I have got the edge and intermediate switches up using lan-automation. I'm asking about the control plane nodes (ISR 4451 routers).

[andy!doesnt!like!uucp]

i wonder what was idea behind your choice of ISR4K as CP

[Parthiv Shah · Accepted solution]

If you configure any device using static underlay, make sure that you don’t use IP address from Lan automation IP address pool range. Once you bring up using static underlay, discover it and then you can provision and configure as CP under fabric. There will not be any change in loopback or physical interfaces done by Cisco dnac. Cisco Dnac will only use the IP address which are already is covered. There is no Lan automation involved in this process. 

[andy!doesnt!like!uucp]

when u add new CP into Fabric shouldnt each & every Fabric Edge node to be configured with this device as MR/MS in FE's router lisp section? how it can be achievable w/o automation?

[Florian.Figula]

Hi all,

yesterday I was presenting Cisco SD-A to the european networking staff during a congress of one of our customers. We came to the question because Cisco itself recommends to use separate Catalyst 8000 Series for CP and BN. Ok, this is supported and sometimes done. Now customer startet deploying devices within an interna POC and was not able to automate fabric links between the campus Catalyst switches and the border or control plane nodes.

In 2.3.5.x there is a feature introduced called "Add link" to provision new and additional fabric links to devices but only if they are already been deployed via LAN Automation. I don't understand why since five years now it's not possible to automate this as well for the routers. It's only a simple Layer-3 configuration with Multicast and IS-IS enabled and two ip addresses needs to be pulled from the pool. Aren't there any recommendations or does no one in business unit know about this? The Customer was not happy with a manual option. You buy a lot of expensive hardware and licences and since five years of SD-A its not possible to automate such an easy thing. There is a lot to do if customers should not dicide to choose other vendors because of such a shame.

[PabMar]

Florian,

I don't think Cisco would have recommended a C8K for B/CP.
The recommendation is a C9K for B/CP which can act as seed devices for LAN Auto. A dedicated CP can be LAN Automated or manually provisioned.

Hope that helps.

Regards.