Explanation:
https://learn.microsoft.com/en-us/azure/expressroute/expressroute-introduction
"Dynamic routing between your network and Microsoft via BGP."
https://learn.microsoft.com/en-us/answers/questions/633891/connecting-multiple-expressroute- circuit-with-a-si
"Yes, it is possible. You can link a single virtual network with up to four ExpressRoute circuits in the same location or up to 16 ExpressRoute circuits in different peering locations.
Reference: https://learn.microsoft.com/en-au/azure/expressroute/expressroute-faqs#can-i-have- one-virtual-network-connected-to-more-than-one-expressroute-circuit ExpressRoutes don't go over the internet, hence ExpressRoute.
Rather, it is strongly recommended that customers setup at least two ExpressRoute circuits to avoid single points of failure"