Cisco I IC 120506
Goals for this IC :
Basic understanding of ethernet technologies
Ethernet is the dominant LAN technology in the world
and has been around since the 1970s.
Give 4 reasons ethernet has been so successful
- simple and easy to maintain
- built to be able to incorporate new technologies
- its reliable
- low cost installation and upgrade
The first Ethernet standard was published in 1980 by a consortium of
Digital Equipment Corporation, Intel, and Xerox (DIX).
Define CSMA/CD: (Carrier Sense Multiple Access with Collision Detection) NIC listens for absence of signal on the network, when there are no signals on the network the NIC will transmit, if two nodes transmit at the same time then there is a collision and none of the nodes transmit.
CSMA/CD access is used by Ethernet and is defined in IEEE specification 802.3.
IEEE 802.3 standard addresses the needs of which 2 layers of the OSI model?
Physical layer and the MAC sub-layer of the Data-Link layer
What is the primary reason ethernet is considered a scalable
implementation?
As size on the network increases the number of different types of Ethernet increase (this is due to the fact that when the network changes generally a new Ethernet standard is released to support the network size)
Give 2 examples of broadband signaling.
IEEE 802.7 (BBTAG) and IEEE 802.16 (BBWA)
Given the descriptor 10BASET what does the T stand for?
Network media (Copper un-shielded twisted pair)
What is the IEEE standard for a token passing bus?
IEEE 802.4
Define and describe OUI.
(Organizational Unique Identifier): The first six hexadecimal digits in the 12 hex MAC address assigned by IEEE that identifies the manufacturer or vendor.
All devices connected to an ethernet LAN have MAC addressed interfaces.
What are the 2 sub-layers of Layer 2 of the OSI model?
MAC physical components and LLC (Logical Link Control) Error control, Flow control, framing, and MAC sub layer addressing.
What is the term given to a Layer 2 PDU?
Frame
Describe the features of a Layer 2 PDU.
A start frame field, an address field, a length/type field, a data field, and a Frame Check Sequence (FCS) field.
Define and describe FCS field.
The extra numbers added to a frame used for error control, this field contains a number calculated by the source node (based on the data in the frame), and then added to the end of the frame. The frame is then sent, when the destination node receives the frame the FCS is recalculated if the numbers are different then the frame is assumed to have errors and is discarded.