Ethernet networks tend to be susceptible to performance problems as they grow, based on the CSMA/CD method of media access that they use. While implementing Layer 2 switching goes a long way towards better Ethernet performance, there are still a number of issues to consider when an Ethernet network begins to experience performance problems. Examples […]

A Cisco 2501 includes a single 10Mb Ethernet port. While many Cisco router models now include an integrated 10/100 RJ-45 port, the 2500 series uses what is referred to as a generic attachment unit interface (AUI) DB-15 port instead. The name for this connector (DB-15) comes from the fact that it is physically shaped like […]

NetWare protocols can run over a variety of different network technologies, similar to TCP/IP. For the purpose of keeping things simple, in this section we’ll concentrate on Ethernet. However, IPX can also be run over Token Ring, FDDI, ATM and a variety of WAN technologies. If you recall, Novell originally defined the 802.3 frame type […]

Up to this point we’ve mainly been looking at the Data Link layer elements of Ethernet. However, Ethernet standards also define Physical layer characteristics such as cable distances, media types, and just about anything to do with physical connectivity, including connectors. You may already be familiar with some of the different varieties of Ethernet. They’re […]

Four different frame types exist in the world of Ethernet, mainly a result of different implementations created for different purposes at different times. Ethernet frame types include Ethernet 802.3, Ethernet 802.2, Ethernet II, and Ethernet SNAP. When two systems need to communicate on an Ethernet network, they must be using a common frame format. The […]

Originally developed by Xerox in the 1970’s, Ethernet has become the defacto technology standard for LANs today. Digital, Intel, and Xerox (DIX) standardized Ethernet in 1980, with the IEEE version finalized in 1982 with the 802.3 standard. Over time Ethernet has undergone a number of changes, both with respect to how devices are connected, and […]

Network topologies describe both the physical and logical layouts of a network. A particular technology such as Token Ring might lead you to believe that the network is physically connected in one big circle of cable. In reality, the ring is formed in circuitry and the physical network appears as a star. Common topologies that […]

There are a variety of methods by which data is merged onto a network, a concept referred to as the media access method. The media access method used depends on the way in which a particular technology such as Ethernet or Token Ring communicates. This section will look at the three most popular methods – […]

Shielded Twisted Pair (STP) cabling is very similar to UTP, with one key difference. STP incorporates an additional conductive foil shielding around each pair of wires. While this helps further cut down on EMI, STP is more expensive and can also be thicker and harder to install than UTP cables. STP cabling is most often […]

Although you may think it unlikely, I can guarantee that you’ll find plenty of network support people in the world who don’t know how to wire a simple patch cable properly. Understanding the roles of the wires in twisted pair cabling goes a long way towards explaining the communication process between connected systems. What we’re […]