ACI Multi Site considerations

[faizal_vi]

Hi ,

We are planning to deploy our redundant DC with another ACI cluster. I would like to know the things which need to considered while deploying the ACI cluster. This will be integrated using MSO.

My main questions are with regard to the Fabric Name, Fabric ID, POD ID , TEP POOL ,VLAN ID and BD Multicast address. Are these values significant to the local cluster only or it should be different while deploying Multi Site?

Thank you.

[Robert Burns · Accepted solution]

Faizal,

We have some great "Ask the Expert" sessions on this topic.  Please see here: https://learningnetwork.cisco.com/s/learning-plan-detail-standard?ltui__urlRecordId=a1c3i0000007oRWAAY&ltui__urlRedirect=learning-plan-detail-standard

One session I'd recommend is titled: Architecture Transformation Planning: Multi-Site for Cisco ACI

For the resources in question, I'd recommend the following:
Fabric Name: Should be unique

Fabric ID: Should always be "1"

POD ID: All fabrics must start with ID 1

Infra TEP POOL: These can be the same as other fabrics, but its our best practice to keep the subnets unique for easier identification

Infra VLAN ID: Our defacto recommendation is 3967, but can be any VLAN ID that you can allocate for ACI use.  Will not be used for cross-site communication and should be ensured not to be a reserved VLAN (internal system VLAN) on any of your other platforms.

BD Multicast address: Should be unique

For some of the IDs/Subnets above, try to come up with a naming plan.  As you hopefully know, MultiSite introduces the concept of a "Site ID", which is used to represent your various sites and populate translation tables for inter-site communication.  I recommend building your Site ID into the other IDs if/where possible.

Ex.  (Keep in mind your numbering system should be mindful of your current & future growth scale.  The example below would account for 98 Leafs per pod and 8 Spines max)

Property	Site1	Site2	Site3
Site ID (MSO)	1	2	2
Fabric ID (APIC)	1	1	1
Infra TEP Pool	10.1.0.0/16	10.2.0.0/16	10.3.0.0/16
Infra VLAN	3967	3967	3967
Spine Node IDs	Pod1: 111-119 Pod2: 121-129 Podx: 1x1-1x9	Pod1: 211-219 Pod2: 221-229 Podx: 2x1-2x9	Pod1: 311-319 Pod2: 321-329 Podx: 3x1-3x9
Leaf Node IDs	Pod1: 1101-1199 Pod2: 1201-1299 Podx: 1x01-1x99	Pod1: 2101-2199 Pod2: 2201-2299 Podx: 2x01-2x99	Pod1: 3101-3199 Pod2: 3201-3299 Podx: 3x01-3x99
BD MCast Range	225.1.0.0	225.2.0.0	225.3.0.0

Regards,

Robert

[waleedmatter]

I have some questions for the Multisite 

1-the BD multicast in site-1 255.1.0.0/16 and for the site-2 255.2.0.0/16 correct ?

 2-the tenant and the VRF can be the same between two sites. 

3-If the GW for the all servers in the two sites is the FW and the ACI in the two sites is L2 so if i will do ISN between two sites , can i stretch one EPG in site-1 to one EPG in site-2 for VM motion ?