NSX-T + Cloud director + shared external subnet between 2 locations

[Leinth]

Hello, 

I'm not sure if it's possible to do this configuration to allow multiple locations to share the same IP subnet (external ip's over bgp) between them within vcloud director. BTW we are using a VCF deployment and it would be 2 different workload domains. 

From what I have thought we would need a t0 VRF router in both locations, connect them over internal BGP, then connect both routers to clients router over external bgp sessions. This should allow subnet ips to talk to each over without touching clients network. Would aggregating subnet in both locations have any effect on accessibility? 

But I'm not really sure how vcloud director would react to this. Has anyone done something similar and have some tips for me? 

[salarmehdizadeh]

hi,

I think that it's NOT a good idea to announce your External IP from more than one site. (it means you can't use an A/A site with the same Ext IP). at the standby site, you should append some data to BGP to use it as a secondary path.

[Leinth]

I wasn't thinking of using the same IP on both sites. I was thinking of splitting the subnet in half. One location would use one half of the pool. It's that the client want's to use their own subnet, but don't have another /24 to announce from a second location. So I would like to stick to NSX-T capabilities as much as possible. 

[Sreec]

I'm hoping these workload domains are from the same site. In theory, what you are trying to do must work, you can still import both the TO/VRF from each workload domain in VCD for Org VDC tenant network connection, and under the hood from NSX do a direct peering between these routes and take care of all filtering if required based on the design. I'm trying to understand, what is the use case ?  

[Leinth]

Answers:

I'm hoping these workload domains are from the same site.

Technically they are on the "same site", but in reality they are divided by ~20 ish miles. 

 I'm trying to understand, what is the use case ?  

Client only has one /24 subnet and wants to use it in both locations. So I'm trying to figure out how to do the configuration under cloud director and nsx-t as much as possible. We would be announcing external IP's to clients router/s over a dedicated lines to our both datacenter locations. 

[Sreec]

the client only has one /24 subnet and wants to use it in both locations.

You are referring VDC VM network OR the BGP network? 

[Leinth]

For the BGP network.

[Sreec]

I would prefer splitting the subnets and keeping a unique VLAN for each site and peer it with the next hop. There is no real need to have a /24 CIDR for the VCD VRF network. 

[ShahabKhan]

Hi,

Do you have any logical diagram which can help in understanding the current environment & what are you trying to achieve?

[Leinth]

Do you have any logical diagram which can help in understanding the current environment & what are you trying to achieve?

No I'm not at that phase yet. I'm just trying to figure out if it's possible to achieve what the client wants. 

We as a provider are running a VCF deployment with 2 workload domains. Those workload domains are in different building. The clients wan'ts to bring his own subnet a single /24 and use it in both workload domains. That's all the information I have from the customer and I'm thinking of how to provide it for the client and if it's even possible to provide.