Chapter 2 - Ethernet Networking and Data Encapsulation

Question 1

Define Ethernet

Answer 1

A contention based, media access method that allows host to share the same links and bandwidth

Question 2

Define Collision Domain

Answer 2

Every device on the segment must process a frame that is sent out. When there is a collision devices must retransmit. Each port on a switch is considered to be a separate collision domain.

Question 3

Define Broadcast Domain

Answer 3

A group of devices that hear all broadcasts sent on the network. Can also refer to a logical segment where devices communicate via a data link

Question 4

What is CSMA/CD

Answer 4

Carrier Sense Multiple Access helps devices share bandwidth while preventing devices from transmitting simultaneously. First it checks the wire and continues to monitor. A jam signal is sent out if another precense is detected.

Question 5

What is Half Duplex

Answer 5

Using CSMA/CD a signal is trasmitted using a one wire pair running in both directions

Question 6

What is Full Duplex

Answer 6

Uses a four wire pair running in both directions simultaneously. Collisions do not happen.

Question 7

Outline the formula for a MAC address

Answer 7

First 24 bits = Organization Unique Identifier
Last 24 bits = Vendor Assigned
Bit # 47 = Individual/Group Bit
- 0 = MAC Address
- 1 = Multicast address
Bit # 46 = Global/local bit or Universal/Local bit
- 0 is globally administered by IEEE
- 1 is locally governed and administered

Question 8

Convert 10000000 to Decimal

Answer 8

128

Question 9

Convert 11000000 to decimal

Answer 9

192

Question 10

Convert 11100000 to decimal

Answer 10

224

Question 11

Convert 11110000 to decimal

Answer 11

240

Question 12

Convert 11111000 to decimal

Answer 12

248

Question 13

Convert 11111100 to decimal

Answer 13

252

Question 14

Convert 11111110 to decimal

Answer 14

254

Question 15

Convert 11111111 to decimal

Answer 15

255

Question 16

What is the name for a single hex character

Answer 16

nibble

Question 17

What is the name for two character hex

Answer 17

byte

Question 18

Convert 0x6A to Decimal

Answer 18

6 = 0110 & A = 1010
= 01101010
= 128 + 64 + 8 + 4

Question 19

What is ‘A’ in binary

Answer 19

1010

Question 20

What is ‘B’ in binary

Answer 20

1011

Question 21

What is ‘C’ in binary

Answer 21

1100

Question 22

What is ‘D’ in binary

Answer 22

1101

Question 23

What is 9 in binary

Answer 23

1001

Question 24

What is an ethernet frame use for

Answer 24

To encapsulate packets passed down from the network layer from some kind of media access

Question 25

Outline the Structure of a frame

Answer 25

Preamble | SFD | Destination | Source |Type | Data & Pad | FCS

Question 26

What is a preamble

Answer 26

Alternating 0 & 1 provides a 5 MHz clock lock on to the data stream

Question 27

What is a start frame delimeter

Answer 27

Preabmle is 7 octets and the SFD is 1 octet. This allows devices to come into the middle of the preamble and still be able to sync up to the beginning.

Question 28

Outline 10BaseTX

Answer 28

802.3 Uses CAT3 up to 100m Devices must connect to a hub or switch Physical Star or Logical bus topology

Question 29

Outline 100BaseTX

Answer 29

802.3U CAT5 up to 100m Two pair wiring Physical Star or Logical bus topology

Question 30

Outline 100Base-FX

Answer 30

802.3U Fiber Cabling - 62.5/125 micron MMF 412 m max Uses ST/SC Connectors

Question 31

Outline 1000Base-CX

Answer 31

802.3z Copper Twisted Pair 25m max Uses special 9 pin connector

Question 32

Outline 1000Base-T

Answer 32

``` 802.3ab CAT5E or higher Uses four pairs (all pairs) 100m max 1 Gbps ```

Question 33

Outline 100Base-SX

Answer 33

802.3z 1 Gbps ethernet over MMF using short wave 62.5 @ 220m & 50 Micron @ 550m

Question 34

Outline 1000Base-LX

Answer 34

``` 802.3z Single mode fiber 9 micron core 1300nm laser 3 km to 20 km ```

Question 35

Outline 1000Base-ZX

Answer 35

This is a cisco standard | Single mode fiber over 70 km

Question 36

Outline 10GBase-T

Answer 36

802.3an CAT 6 or higher 100m max

Question 37

What makes the pin out different on a roll over cable

Answer 37

The ends mirror each other 1-8 2-7 ...

Question 38

What makes the pin out different on a crossover cable

Answer 38

``` T568A on one side and T568B on the other 1 - 3 2 - 6 3 - 1 4 - 7 5 - 8 6 - 2 7 - 4 8 - 5 ```

Question 39

What is a fiber cable made up of and what are the layers to a fiber cable.

Answer 39

Glass or plastic core. The smaller the core the farther the distance Cladding wraps around the core to reflect the light Buffer protects the glass Sheathing wraps the entire thing

Question 40

What protocol data unit is used at the network layer

Answer 40

Packets and Datagrams

Question 41

What protocol data unit is used at the transport layer

Answer 41

Segment

Question 42

What protocol data unit is used at the data link layer

Answer 42

frames

Question 43

What protocol data unit is used at the physical layer

Answer 43

bits

Question 44

What are the steps to processing data from the transmitter

Answer 44

1. User info converted to data for transmission on network 2. Data converted is segmented and reliable connection is established 3. Segments converted to packets/datagrams and logical addressing placed in header 4. Packts/datagrams converted to frames and hardware address used to identify hosts 5. Frames -> bits, digital encoding/clocking scheme used

Question 45

What is a socket

Answer 45

a virtual circuit that is the source/destination port plus the source/destination IP address

Question 46

What are the three layers in the Cisco Hierarchical Model

Answer 46

Core Layer Distribution Layer Access Layer

Question 47

Explain the Core layer in the Cisco Hierarchical Model

Answer 47

- Top - Responsible for transporting large amounts of traffic reliably & quickly - Switch Traffic as fast as possible - Every User loses access when failure - No access lists, no vlans, no packet filtering - Avoid expanding - Upgrades before expansion - Design for reliability - Design for speed Select routing protocols with low convergence times

Question 48

Explain the Distribution layer in the Cisco Hierarchical Model

Answer 48

Workgroup layer provide filtering, routing, and WAN access Implement policies here Redistributing between routing protocols routing between VLAN Defines multicast & broadcast domains

Question 49

Explain the access layer in the Cisco Hierarchical Model

Answer 49

``` Desktop layer Continues use of access creates separate collision domains device connectivity resiliance and security services advance technology capabilities ```