DNA sites interconnection via dark fiber

[Kamran Mustafayev]

Hi,

We are planning to have two geographically separated sites, but they will be connected to each via dark fiber,

Site A has two border/control nodes and several edge nodes behind it, we have fusion routers connected to this border/control nodes which provides external access to DC, now when we are going to connect Site B  to Site A via dark fiber this will be basically one site, with one subnet and segmentation, my question is what will be node mode of Site B switches that will be directly connected to Site A Border/Control nodes?

I attached topology FYI

[balaji.bandi]

Different ways to accomplish the target state depends on what hardware is using to connect fibers

check some guide lines :

https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2020/pdf/BRKCRS-2815.pdf

[jedolphi]

Since you are planning one logical fabric site spread over two physical locations, the site B switches connecting to dark fiber do not require an SDA fabric role, they can be Intermediate Nodes if you wish.

[Kamran Mustafayev]

What will be the role of intermediate node? will it just pass the whole traffic down to site B edge switches ?

[jedolphi]

"Intermediate Node" is SDA nomencalture for "an L3 switch that is not part of the SDA fabric". An IN is not running LISP and is not encapsulating/decapsulating VXLAN, it is just routing packets between Fabric Nodes. So, yes, it would pass traffic between BNs and ENs (S-N flows), or between ENs and ENs (E-W flows).