Uplink redundancy is a method used to ensure that if one physical network interface card (NIC) fails, the network connectivity for the virtual machines (VMs) does not go down. This is typically achieved by configuring multiple NICs to connect to a single virtual switch (vSwitch) and setting up NIC teaming or bonding. The vSwitch manages the internal network traffic between the VMs and the outside network by using the physical NICs assigned to it. By configuring the vSwitch with multiple NICs, you can create redundancy, so if one NIC fails, the other NICs can take over the traffic, ensuring continuous network connectivity.