You can usually trace port connection problems to a poor cable connection or to an improper connection of the port cables at either end of the link. To remedy such problems, make sure that the cable connections are secure and that the cables connect to the correct ports at both ends of the link. If you use homemade cables, ensure that the cables are wired correctly.
1 Gb/s ports operate using Category 5 UTP cabling only. Category 5 UTP cable is a two-pair cable. To minimize crosstalk noise, maintain the twist ratio of the cable up to the point of termination; untwist at termination cannot exceed 0.5 in. (1.27 cm).
Cables for the optical transceivers vary depending on the specific device type.
For more information about the cable requirements for optical transceivers, see Extreme Optics website.