Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 3
IEEE Specifications and their Characteristics
Implementing & Supporting Servers - Chapter 3
IEEE Specifications and their Characteristics
Chapter Overview
The Institute of Electronic and Electrical Engineers (IEEE) developed the standards for the
802 series of networking; in this chapter we will discuss there purpose. Here are some key
points to remember:
Learning Objectives
Objective 1.2:
Specify the main features of 802.2 (LLC), 802.3 (Ethernet),
802.5 (Token Ring), 802.11b (Wi-Fi) and , FDDI network technologies, including:
a) Speed
b) Access
c) Method
d) Topology
e) Media
Lecture Notes
Understanding Project 802 Standards
Project 802 addresses aspects of networking technology. Whenever a new technology, such
as wireless communications, is introduced, a committee is formed to investigate and make
recommendations on that technology. Their results are often published as standards. These
standards are written to address how networking should occur between devices that are using
that particular technology.
802.2: Logical Link Control
The Data Link layer of the OSI Model is divided into two separate sublayers:
1) Media Access control (MAC)
2) Logical Link control (LLC).
The LLC acts as an interface between the MAC sublayer and the Network layer by managing
the data frames. The 802.2 standard defines how network communications should take place
within the LLC layer. The LLC communicates upward to the Network layer using either
connectionless (UDP) or connection-oriented (TCP) mode:
1) Connectionless mode: The LLC simply sends out packets of information, with no
ability to check for errors. Communication tends to be fast. This mode is also known
as a Type 1 operation. UDP is a Type 1 connectionless mode protocol.
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 1 of 3
ISBN: 0-7638-1972-7
Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 3
IEEE Specifications and their Characteristics
2) Connection-oriented mode: After a data transmission the receiving host sends a
message back to the sending host, acknowledging receipt of the information. This
mode is slower but more reliable. It is also known as Type 2 operation. TCP is a
Type 2 connection-oriented mode protocol.
The LLC also monitors the flow of data between hosts and watches for errors using cyclical
redundancy checking (CRC).
802.3: Ethernet (CSMA/CD)
IEEE 802.3 defines the Ethernet networking standards. Also called the DIX method, Carrier
Sense Multiple Access with Collision Detection (CSMA/CD) provides rules concerning how
stations communicate while sharing a common cabling system. IEEE 802.3 Ethernet uses a
logical bus topology, using the following media:
 10Base2 (Thinnet): Thinnet coaxial cable can support data transfer speeds of
10Mbps. Thinnet segments are limited to 185 meters (approx. 607 feet). If additional
length is needed, a repeater is required.
 10Base5 (Thicknet): Thicknet coaxial cable can support data transfer speeds of
10Mbps. Thicknet segments can extend 500 meters (approx. 1,640 feet). If
additional length is needed a repeater is required.
 10Base-T, 100Base-TX, or 1000Base-T (Twisted-pair Ethernet): Unshielded Twisted
Pair (UTP) or Screened Twisted Pair (ScTP) cable supports a data transfer rates of
10Mbps, 100Mbps, and 1Gbps. The segment between network devices (wired as a star)
can extend 100 meters (approx. 328 feet).
802.5 Token Ring (token passing)
Token ring, or token passing networks use a token packet that travels around the ring, from
computer to computer. Since there is only one token, there are no collisions. IEEE 802.5
uses a logical ring topology usually wired as a star (star-wired ring). IBM Token Ring
supports data transfer rates of 4Mbps and 16Mbps, and uses STP (Shielded Twisted Pair),
UTP, or fiber-optic cable.
Fiber Distributed Data Interface (FDDI) LANS and MANS
A type of token passing technology. FDDI utilizes a pair of fiber-optic rings to connect each
device. Each ring contains a single token and the tokens travel in opposite directions
between hosts. If a break or other problem occurs in the primary ring, the secondary ring
acts as a backup, ensuring that data continues to move on the network. FDDI networks are
fault tolerant, support high data transmission speeds, and are commonly used as network
backbones. FDDI can use single-mode or multimode fiber-optic cabling and supports speeds
up to 100Mbps. FDDI can extend to distances up to 60 miles, but is much more expensive to
implement than copper wire (UTP/STP/Coax) based networks. The development of the
newer 100Base-TX (Fast Ethernet) and 1000Base-T (Gigabit Ethernet) technologies are
now replacing FDDI.
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 2 of 3
ISBN: 0-7638-1972-7
Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 3
IEEE Specifications and their Characteristics
802.11: Wireless LANS (CSMA/CA)
IEEE 802.11 provides wireless network access for computing devices regardless of where they
are located physically. Hosts use radio waves (RF) rather than physical network cabling. The
802.11 standard addresses transmission requirements at both the Physical layer and the
Media Access Control sublayer of the OSI Model. The Physical layer handles the actual data
transmission duties between devices. The Media Access Control layer controls the network
access method. The IEEE 802.11 access method is Carrier Sense Multiple Access with
Collision Avoidance (CSMA/CA). IEEE 802.11b Wi-Fi supports wireless network speeds to
11Mbps. IEEE 802.11g raises transmission rates to 54Mbps provided shorter distances are
used.
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 3 of 3
ISBN: 0-7638-1972-7