2.6.3 Cable Category Issues

2.6.3 Cable Category Issues When troubleshooting a permanent link, you should verify that the cable type is appropriate to the application. For example, you cannot expect 10 GbE Ethernet to run over an 80 m Cat 5e link. You may also need to verify that unshielded cable has not been installed where shielded or screened cable would be more suitable. Using an incorrect cable type might result in lower-than-expected speed and numerous checksum errors and link resets. Check the identifier printed on the cable jacket to verify the type that has been used. When evaluating whether a cable category is suitable for a given use in the network, consider the following factors:-Cat 5e supports Gigabit Ethernet and could still be an acceptable choice for providing network links for workstations, but most new installations and upgrades would now use Cat 6 or better.Unlike Ethernet and Fast Ethernet, Gigabit Ethernet uses all four pairs for transmission and is thus more sensitive to crosstalk between the wire pairs.-Cat 6 can support 10 Gbps, but over a 55 m maximum distance.-Cat 6A is an improved specification cable that can support 10 Gbps over 100 m. Cat 6A cable is bulkier than Cat 5e, and the installation requirements more stringent, so fitting it within pathways designed for older cable can be problematic. TIA standards recommend Cat 6A for use in healthcare facilities, with Power over Ethernet (PoE) 802.3bt installations, and for horizontal connections to wireless access points.Cabling is not the only part of the wiring system that must be rated to the appropriate category. For Gigabit Ethernet and better, the performance of connectors becomes increasingly critical. For example, if you are installing Cat 6A wiring, you must also install Cat 6A patch panels, wall plates, and connectors. -Cat 7 cable is always of a screened type and is rated for 10 Gbps applications up to 100 m (328 feet). Cat 7 is not recognized by TIA but appears in the cabling standards created by the ISO (ISO 11801). It must be terminated with GG45 or TERA connectors rather than standard RJ45 connectors.-Cat 8 is intended for use in datacenters only for short patch cable runs that make top-of-rack connections between adjacent appliances. ISO defines two variants; 8.1 (Class I) is equivalent to TIA Cat 8 and uses RJ45 connectors while 8.2 (Class II) must use outer shielding or screening and GG45 or TERA connectors.From a safety point of view, you must also ensure that the cable jacket type is suitable for the installation location, such as using plenum-rated cable in plenum spaces and riser-rated cable in riser spaces.