What is the difference between CAT-5, CAT-5e, CAT-6?:
- CAT-5 is rated to 100M
- CAT-5e is rated to 350M (the e stands for enhanced)
- CAT-6 is rated to 550M or 1000M depending on your source
CAT-6 cable is made with 23 gauge conductor wire as opposed to the slightly smaller 24 gauge for CAT-5e and also has a separator to handle crosstalk better. Both CAT-5 and CAT-5e have 100 ohm impedance and electrical characteristics supporting transmissions up to 100 MHz. CAT-5e components were designed with high-speed gigabit Ethernet in mind, they work with ATM and gigabit speed products. If you are using a 100Mbps switch, get CAT-5e cable. CAT-5e is completely backward compatible with current CAT-5 equipment. The enhanced electrical performance of CAT-5e ensures that the cable will support applications that require additional bandwidth, such as gigabit Ethernet or analogue video.
What is the difference between the types of cable - UTP, Patch, Stranded, Solid and Patch?
- UTP stands for Unshielded Twisted Pair. It is a cable type with pairs of twisted insulated copper conductors contained in a single sheath.
- UTP cables are the most common type of cabling used in desktop communications applications.
- Stranded cable has several small gauge wires in each separate insulation sleeve. Stranded cable is more flexible, making it more suitable for shorter distances, such as patch cords.
- Solid has one larger gauge wire in each sleeve. Solid cable has better electrical performance than stranded cable and is traditionally used for inside walls and through ceilings - any type of longer run of cable.
- Patch Cables are made of stranded copper conductors for flexibility. This construction is great for the flexing and the frequent changes that occur at the wall outlet or patch panel. The stranded conductors do not transmit data signals as far as solid cable. The TIA/EIA 568A which is the governing standard regarding commercial cabling systems limits the length of patch cables to 10 meters in total length.
What is the difference between 10BASE-T, 100BASE-T and 1000BASE-T?
- 10BASE-T is the IEEE standard that defines the requirement for sending information at 10 Mbps on unshielded twisted-pair cabling, and defines various aspects of running Ethernet on this cabling.
- 100BASE-T is the IEEE standard that defines the requirement for sending information at 100 Mbps on unshielded twisted-pair cabling, and defines various aspects of running baseband Ethernet on this cabling.
- 1000BASE-T (also called gigabit Ethernet) is the IEEE standard that defines the requirement for sending information at 1000 Mbps on unshielded twisted-pair cabling, and defines various aspects of running baseband Ethernet on this cabling
What is a cross-over cable?
A cross-over cable is a segment of cable that crosses over pins 1&2 and 3&6. This cable is normally used to connect two PCs without the use of a hub, or can be used to cascade two hubs without using an uplink port. Some DSL modems require a crossover cable to the PC or hub they are connected to.
What are the maximum lengths for cables?
- For Solid UTP: Fast Ethernet 100baseT 100 Meters (328 feet) and Twisted Pair Ethernet 10baseT 100 Meters (328 feet)
- Recommended maximum lengths for Patch Cables made from stranded cable: Fast Ethernet 100baseT 10 Meters (33 feet) and Twisted Pair Ethernet 10baseT 10 Meters (33 feet)
Is CAT-5e backwards compatible?
Yes it works with any 10BaseT or 100BaseT network cards and hubs. CAT-5 is also upwardly compatible with CAT-5e, however your network throughput will only be as fast as the slowest part.
Can I run CAT-5e ethernet cable outside?
CAT-5e cable is not rated for outdoor use, however it can generally be used without a problem. If possible, run the cable through some kind of conduit to prevent moisture or an attractive site for lightning to strike. You should be able to find gray PVC conduit suitable for cable at any hardware store. Remember, 100 Meters is your max distance, without some kind of hub, bridge or amplification.
What is the operating temp for CAT-5e cable?
Operating Temp for CAT-5e cable: -10C to 60C
What is the difference between T568A and T568B wiring?
T568A and T568B are the 2 wiring patterns for 8 position RJ45 modular plug, both permitted under the TIA/EIA 568A wiring standards document. The only difference between the two pattern is that the pairs 2 (orange) and 3 (green) are interchanged. All our cables use T568B standards.
What is EMI and how can you prevent it?
EMI stands for Electro-Magnetic Interference. It is potentially harmful to your communications system because it can lead to signal loss and degrade the overall performance of high-speed, CAT-5e cabling. EMI is interference in signal transmission or reception and is caused by the radiation of electrical or magnetic fields which are present near power cables, heavy machinery, or fluorescent lighting. Avoiding EMI is as simple as not laying your network cable within 12" of electrical cable, or if needed switching from UTP to more expensive shielded cable.
Just tell me what cable I need...
If you need patch cords up to 25 feet, use CAT-5e stranded cable for ease of flexibility. If you are making linger runs or going through walls or ceilings, use the CAT-6 UTP (solid) cables or CAT-5e UTP.
What is a network switch?
A network switch is an Ethernet device that can divided an Ethernet network up in different zones. Within one zone all computers will se each others traffic but outside the zone only traffic that is aimed for computer in that zone is transferred.
When computers on one side of the switch communicate with each other the switch will not forward their traffic to the other side. The switch keeps track where computers are connected to the bus based on there MAC-addresses and only forward traffic if computers that communicate are in another zone, in this case on the other side. Devices on an Ethernet network will not detect or notice the network switches. For computers the switches are transparent.
A network switch keeps track of computers connected behind the switch and only data packets that have there destination MAC-address set to a computer behind the switch are forwarded to the computers behind the switch. This is true for most cases, but not all. When a computer tries to connect to a network it sends out broadcast packets. Broadcast packets have no specific destination address. Instead the broadcast packets are meant for all computers on the network. A connecting computer sends those packets to inform all the other computers on the network that it is about to become part of the network. These broadcast packets will switches forward to all computers behind them.
When a new computer connects to the network it has to let the other computers know its there. The new computer has no idea of what other computers that are already there. The computers already on the network have no way of telling there is a new computer connected to the network. The new computer therefore sends out several broadcast packets on Ethernet level and the new computer puts its own MAC-address as the sender MAC-address. But since the new computer does not know what other MAC-addresses that are used by the other computers it sets the destination MAC-address to all "1"s (broadcast destination address 0xFF-FF-FF-FF-FF-FF). Switches recognise the destination MAC-address as a broadcast address and forward the packet to the zone behind the switch. This is since the switch can not tell for what MAC-address the packet is meant. This means that a computer that sends out a broadcast packet can rely on that all the other computer and other network devices on the network will receive the broadcast packet even if the network is divided in zones by switches. Of cause this is not hundred percent true since there is something today called Virtual LAN. For now we assume that all computers on a local network will receive these broadcast packets which are not only sent when a computer connects to the network but are sent now and then for other purposes. Typical a computer sends out a broadcast packet every third minute.
MAC-address and IP-address?
MAC-addresses are used on local Ethernet networks. IP-addresses are more abstract and can be used on top of multiple types of networks.
Where do IP-addresses come in?
Local networks like an Ethernet network sends all traffic to all computers that sit on the same network bus. Global networks like the Internet will not send all traffic to all of the connected computers. IP-communication (that is used on the Internet) has a much more sophisticated way to deal with sending and routing the data communication. IP-communication is very useful on local networks as well but we have to separate the physical part of the network from the logical part as the communication difference between the physical and the logical part of the networks goes within a grey area in software.
To the physical (hardware) domain belong cables and network cards. Ones the data signals have been detected on the network card the low level software on the card and in the operating system takes on the task to process this data. That processing is divided in different levels.
There are standard models for this level of software. One such model is called the OSI model and has 7 levels.
On an Ethernet network you do not have to use IP-communication to communicate. Before the Internet become popular and dominating other protocols like NOVELL IPX was common on local networks. Many companies already have working local networks when Internet and IP-communication become popular. However there is no problem running several different protocols at the same time on an Ethernet network as long as all "physical" (low level) communication uses the fundamental Ethernet rules using Ethernet frames with source and destination MAC-addresses. Today the majority of Ethernet networks only run the IP-protocol.
Network packets are like Russian dolls. An IP-packet resides within an Ethernet-packet. A TCP-packet resides within an IP-packet. A HTTP-packet resides within a TCP-packet. The data part of an Ethernet packet can hold up to 1500 bytes. MAC-addresses (48bits) are 6 bytes wide each and the Number of Bytes field is 2 byte wide. That gives the maximum size of an Ethernet frame to be 1514 bytes.
When introducing the IP-protocol on Ethernet the Number of Bytes field is used to mark that the Ethernet frame holds an IP-packet by the number of 0x0800. By using a number that is greater than the maximum length an Ethernet frame can hold indicates that the Ethernet frame holds another protocol frame in the data part. The Ethernet standard says that if the Number of Bytes field is greater than 0x0600 the Ethernet frame holds another protocol.
Clients and/or Servers?
In general, all machines on the Internet can be categorised as two types: servers and clients. Those machines that provide services (like Web servers or FTP servers) to other machines are servers. And the machines that are used to connect to those services are clients. When you connect to Yahoo! at www.yahoo.com to read a page, Yahoo! is providing a machine (probably a cluster of very large machines), for use on the Internet, to service your request. Yahoo! is providing a server. Your machine, on the other hand, is probably providing no services to anyone else on the Internet. Therefore, it is a user machine, also known as a client. It is possible and common for a machine to be both a server and a client, but for our purposes here you can think of most machines as one or the other. A server machine may provide one or more services on the Internet. For example, a server machine might have software running on it that allows it to act as a Web server, an e-mail server and an FTP server. Clients that come to a server machine do so with a specific intent, so clients direct their requests to a specific software server running on the overall server machine.