I have to redesign the network at site. Currently the setup is there is a core switch which is on stack and one router at site. 2 WAN links are terminating on same router. No we are changing the design to have 2 core-switches at site which will work in hsrp and one router. For redundancy purpose, I am planning to have connection from one core-switch to router port and second connection from another core-switch to same router another port. Can you please advise this design will work? How can this be accomplished or if this is not correct design what other options we can have. site has only one router.
What kind of core switch are you planning to use? If you have 2 catalyst VSS capable, or 2 Nexus in vpc configuration, you can make a port-channel from your router, one member to one switch and the other member to the other one and connect all together like you are planning.
Depending on the number of copper and fiber ports you need, you can use one of the 6800 series model switches and use VSS, so both core switches work as one device. You can then connect both switches to your router using a layer-3 Portchannel. You can use Sup-2T or the new Sup-6T.