ACI Multi-Site Initialization question

m1xed0s · ‎12-22-2020

I have two Datacenters and I need to setup ACI multi-site for brownfield migration. To initialize each ACI Fabric for preparing the Multi-Site setup, I need to configure Fabric name, ID, Infra VLAN/Subnet and MCast for each. So the questions I have:

1. Can Fabric ID be the same for the two sites?

2. Can Infra VLAN (not subnet) to be the same for the two sites?

3. Is VLAN 4 reserved strictly for ISN/IPN network? In other words, I can not use VLAN4 as Infra VLAN, right?

4. If #3 is true, what happens if VLAN 4 is used already as Data VLAN within Datacenter?

ACI Code v4.2.

Thanks!

Robert Burns · ‎12-22-2020

1. Can Fabric ID be the same for the two sites?

Robert - Yes. Fabric ID should always be "1". There's no longer any use case for changing this. Site ID is assigned by MSite and the differentiating identifier.

2. Can Infra VLAN (not subnet) to be the same for the two sites?

Robert - Yes.

3. Is VLAN 4 reserved strictly for ISN/IPN network? In other words, I can not use VLAN4 as Infra VLAN, right?

Robert - The IPN/ISN VLAN is strictly for the OSPF connection between Spines and ISN. This doesn't impact the ability to use VLAN 4 as a User/Data VLAN. This infra VLAN is in its own VRF.

4. If #3 is true, what happens if VLAN 4 is used already as Data VLAN within Datacenter?

Robert - Not an issue.

m1xed0s · ‎12-22-2020

Thanks!!!

3. Is VLAN 4 reserved strictly for ISN/IPN network? In other words, I can not use VLAN4 as Infra VLAN, right?

Robert - The IPN/ISN VLAN is strictly for the OSPF connection between Spines and ISN. This doesn't impact the ability to use VLAN 4 as a User/Data VLAN. This infra VLAN is in its own VRF.

So just I am clear, I could use VLAN 4 as the ACI Infra VLAN while perform OSPF peering for ISN/IPN via VLAN4?

m1xed0s · ‎12-22-2020

1. Can Fabric ID be the same for the two sites?

Robert - Yes. Fabric ID should always be "1". There's no longer any use case for changing this. Site ID is assigned by MSite and the differentiating identifier.

It would not cause any issue if I used Fabric ID 1 for one site and Fabric ID 2 for the second site, right? I thought there was some specific use case, may be GOLF?, that the Fabric IDs must be unique...Maybe it is irrelevant now with v4.2 or 5...