Chapter 4 Flashcards
(MAC)stands for what. p88
Media Access Control (MAC)
(DNS)stands for what. p89
Domain Name Service (DNS)
what is Ethernet. p90
is a contention media-access method that allows all hosts on a network to share the same bandwidth of a link.
what is a Collision Domain p90
is an Ethernet term that refers to a particular network scenario wherein one device sends a packet out on a network segment, thereby forcing every other device on that same physical network segment to pay attention to it.
a situation where each device’s digital signals interfere with another on the wire—occurs and forces the devices to retransmit later. p90
collision event
Ethernet uses both Data Link and Physical layer specifications. true or false p90
True
what is a Broadcast Domain p90
A broadcast domain refers to the set of all devices on a network segment that hear all the broadcasts sent on that segment.
a protocol that helps devices share the bandwidth evenly without having two devices transmit at the same time on the network medium. p91
Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
When a collision occurs on an Ethernet LAN, the following happens: p92
A jam signal informs all devices that a collision occurred.
The collision invokes a random backoff algorithm.
Each device on the Ethernet segment stops transmitting for a short time until the timers expire.
All hosts have equal priority to transmit after the timers have expired.
And following are the effects of having a CSMA/CD network sustaining heavy collisions: p92
Delay
Low throughput
Congestion
Full-duplex Ethernet can be used in many situations; here are some examples: p93
With a connection from a switch to a host
With a connection from a switch to a switch
With a connection from a host to a host using a crossover cable
This rate is something known as an __________which translates as “you’re supposed to get” 100 percent efficiency. p93
aggregate rate
You can run full duplex with just about any device except a hub. true or false p93
true
Ethernet at the Data Link layer is responsible for Ethernet addressing, commonly referred to as what. p94
hardware addressing or MAC addressing
are made up of hexadecimal addresses. p94
Ethernet MAC addresses
(MAC)stands for what. p98
Media Access Control (MAC)
(OUI)stands for what. p98
organizationally unique identifier (OUI)
(CRC)stand for what. p99
cyclic redundancy check (CRC)
An alternating 1,0 pattern provides a 5MHz clock at the start of each packet, which allows the receiving devices to lock the incoming bit stream. p99
Preamble
The preamble is seven octets, and the SFD is one octet (synch). The SFD is 10101011, where the last pair of 1s allows the receiver to come into the alternating 1,0 pattern somewhere in the middle and still sync up and detect the beginning of the data. p99
Start Frame Delimiter (SFD)/Synch
This transmits a 48-bit value using the least significant bit (LSB) first. The DA is used by receiving stations to determine whether an incoming packet is addressed to a particular host. The DA can be an individual address or a broadcast or multicast MAC address. Remember that a broadcast is all 1s (or Fs in hex) and is sent to all devices, but a multicast is sent only to a similar subset of hosts on a network. p99
Destination Address (DA)
is a 48-bit MAC address used to identify the transmitting device, and it uses the LSB first. p100
Source Address (SA)
what is a Length or Type p100
802.3 uses a Length field, but the Ethernet frame uses a Type field to identify the Network layer protocol. 802.3 by itself cannot identify the upper-layer routed protocol and must be used with a proprietary LAN—Internetwork Packet Exchange (IPX)
This is a packet sent down to the Data Link layer from the Network layer. The size can vary from 64 to 1500 bytes. p100
Data
is a field at the end of the frame that’s used to store the CRC. p100
Frame Check Sequence (FCS)
s a computer-networking arrangement where two or more network interfaces on a host are combined for redundancy and/or increased throughput. p101
Channel bonding (also known as Ethernet bonding)
Each Ethernet cable type that is specified by the EIA/TIA has something known as. p102
inherent attenuation
