Week 9

Question 1

Shared medium

Answer 1

Not about sharing among different devices from the same subscriber as in FDM or about sharing among end users. It is about “Sharing Among Subscribers”

Question 2

How Data are Packaged

Answer 2

Application (layer five is the application) -> OS -> Networking software (layer four which is protocols, three which is network) -> NIC (layer two of link layer and one of physical layer).

Small numbers are chopped up and sequenced with sequence numbers in multiple headers.

Question 3

MAC address

Answer 3

is unique to each devices as allocated by an organization

used at layer two

Question 4

IP Address

Answer 4

used for layer three

Question 5

Encapsulation

Answer 5

Adding and removing data headers

Question 6

Layer 2

Answer 6

Switches operating between devices

Question 7

Layer 3

Answer 7

Router connecting devices across networks

Question 8

LO

Answer 8

Loopback IP address

Question 9

NIC

Answer 9

Most functionality implemented in ROM, read only memory.

Uses direct memory access to be more efficient

One per port of a router and none in a switch to deal with Manchester encoding, etc.

Question 10

DMA

Answer 10

Direct memory access.

Question 11

BUS

Answer 11

Bundle of wires (Binary Unit System). Needs eight wires for each bit of a byte. Connects from the NIC to the host.

Question 12

Word Size

Answer 12

Number of bytes moved around a processor at once. Today it is eight.

Question 13

Ethernet cable

Answer 13

Eight wires total. Can be four to eight used for data and the rest for power supply.

Must perform clock synchronization.

Question 14

Clock speed

Answer 14

We are reaching physical limits of how fast it can be

Question 15

PISO

Answer 15

Paralel in serial out.

Used for sending data out of a NIC

Question 16

SIPO

Answer 16

Serial in parallel out.

Used for getting data out of an NIC

Question 17

Thunderbolt

Answer 17

Runs in parallel, but the wire must be very short because its not robust against electromagnetic noise.

Question 18

Manchester encoding

Answer 18

Part of data protection done by the NIC

Question 19

Packet loss

Answer 19

Data corruption and link layer switches having full queues

Question 20

TTL

Answer 20

Time to live in number of hops, not auctual time

Question 21

Traceroute

Answer 21

Three probes sent to each hub by varying time to live.

Average delay should decrease, but can increase.

Only reveals minimum number of hops.

Question 22

Queueing delay

Answer 22

Time spent in a queue

Question 23

Processing delay

Answer 23

Time spent adding Manchester encoding

Question 24

Transmission delay

Answer 24

Time spent on wires

Question 25

Propogation delay

Answer 25

Time it takes NIC to output data.