Design Use Cases

[fatalXerror]

Hi,

Really new in ACI environment.

I read and watched multiple articles/how-tos and videos about ACI logical design but I am not sure which is the best or applicable for a data center if it has the following:

1. Multisite DC (PDC/DR)

2. Both DC have the same IP address design

I read and watch some stretched their BD and EPG and some they just stretched their EPGs. Wondering what is the use case why they are stretching it? Is it because their multiple site have the same IP scheme also? 

Hoping someone can enlighten me.

Thank you

[ecsnnsls]

Hi,

If you want your DC to be active/active then it is best to use a Multipod setup. This setup has Layer 2 and Layer 3 interconnectivity between DCs from Day-0.

If you want DC/DR setup, it is best to use Multisite. You can stretch BDs if you want enable clustering or perform live migrations between the DCs on demand. Multisite gives you this flexibility.

[fatalXerror]

Hi @ecsnnsls , thanks for the feedback. But I can still do active/active setup with MultiSite but I need to have 2x different subnets for each sites, correct?

[ecsnnsls]

Hi, Yes you can still do active/active with the same IP subnet in the same BD on two sites if you want to. You need to enable L2 stretch along with INTERSITEBUMTRAFFICALLOW(if you have BUM requirement).

I think it is best to use Multipod if you have lots of inter DC traffic with active/active paths.

[fatalXerror]

Hi @ecsnnsls , sorry just to clarify things, if I say same subnet, it is also consist of the same IP in the server level connecting to both sites, will this be still possible even if I stretch the L2 between the sites?

[ecsnnsls]

The IPs should be unique on the servers. the subnet on the bridge domain can be the same.