vSphere Standard Switch settings control switch-wide defaults for ports, which can be overridden by port group settings for each standard switch. You can edit standard switch properties, such as the uplink configuration and the number of available ports.
Number of Ports on ESXi Hosts
To ensure efficient use of host resources on hosts running ESXi 5.5 and later, the ports of virtual switches are dynamically scaled up and down. A switch on such a host can expand up to the maximum number of ports supported on the host. The port limit is determined based on the maximum number of virtual machines that the host can handle.
Each virtual switch on hosts running ESXi 5.1 and earlier provides a finite number of ports through which virtual machines and network services can reach one or more networks. You have to increase or decrease the number of ports manually according to your deployment requirements.