1 00:00:00,470 --> 00:00:04,670 The Gigabit Ethernet standard requires that all pins be connected. 2 00:00:04,880 --> 00:00:12,680 So this is an example of a crossover cable four gigabit using the DT 568b standard. 3 00:00:12,830 --> 00:00:16,280 Notice all pins are configured in a crossover fashion. 4 00:00:16,400 --> 00:00:19,970 All four pairs of wires are used in this example. 5 00:00:20,060 --> 00:00:26,000 Now, in the past, you'd have to know when to use a straight through or crossover cable. 6 00:00:26,240 --> 00:00:29,450 Any of these implementations would use a straight through cable. 7 00:00:29,450 --> 00:00:30,830 So router to switch. 8 00:00:30,830 --> 00:00:32,030 PC to switch. 9 00:00:32,060 --> 00:00:34,760 PC to bridge or PC to hub. 10 00:00:35,590 --> 00:00:39,270 Any of these implementations would use a crossover cable. 11 00:00:39,280 --> 00:00:48,880 So rather to rudder switch to switch PC to PC or hub to hub or bridge to switch PC to server, hub to 12 00:00:48,880 --> 00:00:55,240 switch and once again, router to router all require crossover cables. 13 00:00:55,570 --> 00:01:01,120 However, today, automatic crossover or auto mdex is widely used. 14 00:01:01,360 --> 00:01:09,130 Auto Mdex was introduced in 1998 and it made the requirement for crossover cables obsolete. 15 00:01:09,490 --> 00:01:12,950 MDI devices are typically routers or PCs. 16 00:01:12,970 --> 00:01:21,430 MDI devices are typically switches or hubs, so they are medium dependent interface crossover devices. 17 00:01:21,430 --> 00:01:27,730 And in the past you would need to connect an MDI device such as a PC to a switch or hub. 18 00:01:27,850 --> 00:01:35,710 In the old days, once again, certain ports would have a button to flip the role from MDI to MDI, 19 00:01:35,710 --> 00:01:40,540 which would allow you to connect a switch to a switch using a straight through cable. 20 00:01:40,570 --> 00:01:44,470 However, today, in a lot of cases, auto MDI. 21 00:01:44,500 --> 00:01:49,180 MDI allows for automatic switching once the cable is connected. 22 00:01:49,690 --> 00:01:56,530 The devices can order detect the cable type, so there's no need to worry as much about cable types 23 00:01:56,530 --> 00:01:57,280 today. 24 00:01:57,310 --> 00:02:01,420 A straight through cable as an example, could be used between hubs or between switches. 25 00:02:01,630 --> 00:02:08,470 So in the past you used to have to use a crossover cable between two switches, but that's not necessarily 26 00:02:08,470 --> 00:02:09,970 required today. 27 00:02:10,270 --> 00:02:15,850 Straight through cables could be used and devices would work out which side is MDI and which side is 28 00:02:15,850 --> 00:02:16,900 MDX. 29 00:02:16,930 --> 00:02:18,700 However, be careful. 30 00:02:18,700 --> 00:02:25,810 That's not always true when on site you may encounter an older Cisco switch that doesn't support or 31 00:02:25,810 --> 00:02:27,310 to MDI MDI. 32 00:02:27,910 --> 00:02:33,220 So you may have to use the correct cabling type between older devices. 33 00:02:34,400 --> 00:02:36,470 There are various categories of cable. 34 00:02:36,500 --> 00:02:44,090 In general, the higher the category, the more twists and the less susceptible the cable is to electromagnetic 35 00:02:44,090 --> 00:02:45,140 interference. 36 00:02:45,620 --> 00:02:52,470 The higher the category, the more stringent the specifications are for crosstalk and system noise. 37 00:02:52,490 --> 00:02:58,010 Higher cable categories typically support higher frequencies and higher speeds. 38 00:02:58,370 --> 00:03:02,660 I wouldn't try to remember all the categories of cable if I were you. 39 00:03:02,900 --> 00:03:09,500 Just see this as an explanation of the various categories you may encounter in networks or in documentation. 40 00:03:09,800 --> 00:03:13,550 Category one was previously used for telephones and modems. 41 00:03:13,940 --> 00:03:20,000 So Category one is a grade of unshielded twisted pair cabling designed for telephone communications 42 00:03:20,000 --> 00:03:23,360 and was at one time the most common on premise wiring. 43 00:03:23,390 --> 00:03:26,480 This is not suitable for data transmission. 44 00:03:26,840 --> 00:03:32,480 Category two was previously used for telephones and data networks up to four megabits per second. 45 00:03:32,990 --> 00:03:38,090 Category three was used previously for data networks up to ten megabits per second. 46 00:03:38,450 --> 00:03:41,270 It's now generally used for telephones. 47 00:03:41,900 --> 00:03:47,630 Category four is defined up to 20 megahertz, with speeds up to 16 megabits per second. 48 00:03:48,140 --> 00:03:54,890 Category five is defined up to 100 megahertz speeds of ten or 100 megabits per second when using two 49 00:03:54,890 --> 00:03:58,520 pairs and one gigabits per second when using four pairs. 50 00:03:58,760 --> 00:04:01,700 Category one, two and four are no longer used. 51 00:04:01,730 --> 00:04:07,880 Category three is no longer used in data networks, and generally category five is no longer used. 52 00:04:07,880 --> 00:04:12,320 But there's a lot of installations that have category five, so you may still come across. 53 00:04:12,320 --> 00:04:16,200 It kept five was an improvement on Cat five. 54 00:04:16,220 --> 00:04:21,940 It supports frequencies up to 100 megahertz and supports speeds up to one gigabits per second. 55 00:04:21,950 --> 00:04:29,150 It has a maximum distance of 100 meters and is similar to Cat five but improved the CAT five specification 56 00:04:29,150 --> 00:04:32,450 by reducing noise and signal interference. 57 00:04:32,450 --> 00:04:36,320 So some crosstalk was improved with the new specification. 58 00:04:36,710 --> 00:04:43,550 The Category five specification improves upon the Category five specification by tightening some crosstalk 59 00:04:43,550 --> 00:04:50,540 specifications and introducing new crosstalk specifications that were not present in the original Category 60 00:04:50,540 --> 00:04:51,830 five specification. 61 00:04:51,830 --> 00:04:55,430 The bandwidth of Cat five and Cat five is the same. 62 00:04:55,430 --> 00:04:59,990 In other words, 100 megahertz, and the physical cable construction is the same. 63 00:04:59,990 --> 00:05:06,560 And the reality is that most Cat five cables meet Cat five E specifications, though it may not be tested 64 00:05:06,560 --> 00:05:08,210 or certified as such. 65 00:05:08,750 --> 00:05:16,070 Category six defines frequencies up to 250 megahertz and increases the number of pair twists per inch 66 00:05:16,070 --> 00:05:19,010 to reduce signal noise and interference. 67 00:05:19,070 --> 00:05:23,360 It supports ten gigabits per second, but only up to 55 meters. 68 00:05:23,600 --> 00:05:30,110 The top of specifications and Cat six guarantee 100 meter runs at one gigabits per second. 69 00:05:30,380 --> 00:05:37,100 So Category six cable, commonly referred to as Cat six, is a standardised cable for gigabit Ethernet 70 00:05:37,100 --> 00:05:44,210 and is backward compatible with Category five or Category five and Category three cable standards compared 71 00:05:44,210 --> 00:05:46,370 to Cat five or Cat five. 72 00:05:46,400 --> 00:05:52,580 Cat six features more stringent specifications for crosstalk and system noise. 73 00:05:52,580 --> 00:05:59,780 The Cable Standard provides performance up to 250 megahertz and is suitable for ten bass TW 200 bass, 74 00:05:59,780 --> 00:06:08,120 TCS or Fast Ethernet and 1000 bass RT or gigabit Ethernet as well as ten gigabit Ethernet Category six 75 00:06:08,120 --> 00:06:16,910 A or augmented category six defined frequencies up to 500 megahertz, which is twice that of Cat six. 76 00:06:17,120 --> 00:06:23,510 It also includes improvements with regards to crosstalk and support speeds up to ten gigabits per second. 77 00:06:23,510 --> 00:06:30,170 But in this case, with the extended cable length of 100 meters Category six, maximum cable length 78 00:06:30,170 --> 00:06:37,280 was 55 meters in a favorable environment, but only 37 meters in an environment where a lot of crosstalk 79 00:06:37,280 --> 00:06:40,750 took place, such as when cables are bundled together. 80 00:06:40,760 --> 00:06:47,600 So Category six A or Cat six improved the specification, allowing for ten gigabits per second up to 81 00:06:47,600 --> 00:06:48,710 100 meters. 82 00:06:49,010 --> 00:06:56,270 Category seven or Cat seven defined frequencies up to 600 megahertz and support speeds of up to ten 83 00:06:56,270 --> 00:06:59,240 gigabits per second up to 100 meters. 84 00:06:59,600 --> 00:07:07,820 The connectors in Cat seven can be terror connectors rather than eight PHC or eight position eight contact, 85 00:07:07,820 --> 00:07:11,750 which we commonly referred to as an RJ 45 connector. 86 00:07:11,870 --> 00:07:16,400 So here's an example of a terror connector and Cat seven notice. 87 00:07:16,400 --> 00:07:21,080 The pairs of cable in Cat seven are protected by a foil shield. 88 00:07:21,170 --> 00:07:28,010 The twisting of pairs and the number of turns per inch is also increased to protect from crosstalk and 89 00:07:28,010 --> 00:07:29,900 in addition has a ten copper twin. 90 00:07:29,900 --> 00:07:33,530 X Category seven is also known as KLOS f. 91 00:07:33,920 --> 00:07:42,380 And also has a clause F a which defined frequencies up to 100 megahertz per second and which in theory 92 00:07:42,380 --> 00:07:48,440 supports speeds up to 40 gigabits per second and 100 gigabits per second at 15 meters. 93 00:07:48,620 --> 00:07:54,030 This is currently an ISO or ISO standard but is not recognized by the EIA. 94 00:07:54,080 --> 00:07:54,920 EIA. 95 00:07:55,400 --> 00:08:01,580 For brand new installations, it's generally recommended that Cat six A or Cat seven be used. 96 00:08:02,120 --> 00:08:10,280 If reusing existing Cat six cabling cable segments must be tested up to 350 megahertz and limited by 97 00:08:10,280 --> 00:08:12,710 TIA EIA recommendations. 98 00:08:12,740 --> 00:08:20,630 Now Category eight is the next generation twisted cabling specification and is being developed to support 99 00:08:20,630 --> 00:08:22,320 40 gigabits per second. 100 00:08:22,340 --> 00:08:25,460 In other words, four times the speed of ten gigabit Ethernet. 101 00:08:25,790 --> 00:08:32,450 The technical recommendation for Category eight was released in March 2013 and has both clause one and 102 00:08:32,450 --> 00:08:33,559 clause two. 103 00:08:33,590 --> 00:08:38,510 In other words, Category 8.1 cable and Category 8.2 cables. 104 00:08:38,720 --> 00:08:47,270 Category 8.1 is fully backward compatible and interoperable with Category six A using RJ 45 connectors. 105 00:08:47,600 --> 00:08:55,790 Category 8 to 2 is interoperable with Category seven cabling using either RJ 45 or terra connectors.