where do we use cross and standard cable
Ethernet crossover cable Intentionally crossed wiring in the crossover cable connects the transmit signals at one end to the receive signals at the other end. Many devices today support Auto MDI-X capability, wherein a patch cable can be used in place of a crossover cable, or vice versa, and the receive and transmit signals are reconfigured automatically within the devices to yield this desired result.
Category 6 cable When used for 10/100/1000BASE-T, the maximum allowed length of a Cat 6 cable is up to 100 meters (328 ft). This consists of 90 meters (295 ft) of solid "horizontal" cabling between the patch panel and the wall jack, plus 5 meters (16 ft) of stranded patch cable between each jack and the attached device.[7] For 10GBASE-T, an unshielded Cat 6 cable should not exceed 55 meters.[8]