Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.
I understand that you would like to know about the potential impacts on sharing ExpressRoute Circuits across Tenants.
I can confirm you that there are NO impact on one tenant's users when you share the ExpressRoute Circuit with other tenant's users.
However, you should make sure the bandwidth usage is within the bandwidth you procured for your ExpressRoute Circuit. (post creating connection)
- See : Bandwidth options
- Again, this is not a result of having two tenants, rather having many users.
- If you were to increase the number of users utilizing the ExpressRoute in the single tenant - the same logic applies.
Other than that, you do not have any direct impacts on creating an ExpressRoute Connection across Tenants.
Kindly let us know if this helps or you need further assistance on this issue.
Thanks, Kapil
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