@IH ,
Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.
A single ExpressRoute circuit consists of two connections to two Microsoft Enterprise edge routers (MSEEs) at an ExpressRoute Location from the connectivity provider or your network edge.
The recommendation on the customer side, is to have 2 distinct edge routers only - as this will be better suited for redundancy and high availability.
Nevertheless, you can use a single edge router at your end ,
- However, the connectivity provider always uses redundant devices
From ExpressRoute requirements,
- You must reserve a
/29
subnet or two/30
subnets for routing interfaces. - See : IP addresses used for Azure private peering
- As the provider always uses a redundant device,
- For each of the
/30
subnets, Provider uses the first IP address of the/30
subnet for their router (Provider Edge) - Microsoft uses the second IP address of the
/30
subnet to set up a BGP session.
- For each of the
You can contact your provider to see how they can hand off traffic to a single router at your end (CE)
Cheers,
Kapil.