Network Topology

A network consists of multiple computers connected using some type of interface, each having one or more interface devices such as a Network Interface Card (NIC) and/or a serial device for PPP networking. Each computer is supported by network software that provides the server or client functionality. The hardware used to transmit data across the network is called the media. It may include copper cable, fiber optic, or wireless transmission. The standard cabling used for the purposes of this document is 10Base-T category 5 ethernet cable. This is twisted copper cabling which appears at the surface to look similar to TV coaxial cable. It is terminated on each end by a connector that looks much like a phone connector. Its maximum segment length is 100 meters.

The Data Link Layer and IEEE

When we talk about Local Area Network (LAN) technology the IEEE 802 standard may be heard. This standard defines networking connections for the interface card and the physical connections, describing how they are done. The 802 standards were published by the Institute of Electrical and Electronics Engineers (IEEE). The 802.3 standard is called ethernet, but the IEEE standards do not define the exact original true ethernet standard that is common today. There is a great deal of confusion caused by this. There are several types of common ethernet frames. Many network cards support more than one type.

• 802.1 - Internetworking
• 802.2 - Logical Link Control
• 802.3 - Ethernet or CSMA/CD, Carrier-Sense Multiple Access with Collision detection LAN
• 802.4 - Token-Bus LAN
• 802.5 - Token Ring LAN 
• 802.6 - Metropolitan Area Network (MAN)
• 802.7 - Broadband Technical Advisory Group
• 802.8 - Fiber-Optic Technical Advisory Group
• 802.9 - Integrated Voice/Data Networks
• 802.10 - Network Security
• 802.11 - Wireless Networks
• 802.12 - Demand Priority Access LAN, 100 Base VG-AnyLAN
• A LAN (local area network) is a group of computers and network devices connected together, usually within the same building. By definition, the connections must be high speed and relatively inexpensive (e.g., token ring or Ethernet). Most Indiana University Bloomington departments are on LANs. For more information on LANs,

   A MAN (metropolitan area network) is a larger network that usually spans several buildings in the same city or town. The IUB network is an example of a MAN.

  A WAN (wide area network), in comparison to a MAN, is not restricted to a geographical location, although it might be confined within the bounds of a state or country. A WAN connects several LANs, and may be limited to an enterprise (a corporation or an organization) or accessible to the public. The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN.

  A LAN connection is a high-speed connection to a LAN. On the IUB campus, most connections are either Ethernet (10Mbps) or Fast Ethernet (100Mbps), and a few locations have Gigabit Ethernet (1000Mbps) connections