Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Network+ > C2. The Open System Interconn. Specs > Flashcards

C2. The Open System Interconn. Specs Flashcards

1
Q

Name the 7 layers of the OSI model?

A

Application, Presentation, Session, Transport, Network, Data Link, Physical (Anya presented star trek near dark leaky pipe)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does OSI stand for btw?

A

Open System Interconnection luv =)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the key role of the Application layer?

A

It acts as an interface between applications and programs (e.g. Microsoft Word does not reside in the app layer, it interfaces with the App Layer protocols)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

At which layers do users communicate with the computer?

A

Application!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does a computer find at the application layer?

A

1) available communication partners

2) resources for communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three key roles of the presentation layer?

A

1) it controls data integrity and error recovery
2) it presents data to the application level
3) it’s responsible for data transmission and formatting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the session layer do?

A

It sets up, manages, and tears down sessions between the presentation layer entities (data of all apps is kept separately as a result!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the three modes of the session layer?

A

Simplex, half duplex, full duplex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the transport layer do?

A
  • It segments and reassembles data into a data stream, where all the data segments unite again
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the data stream of the transport layer do?

A
  • Data stream provides end-to-end transport services and establishes a logical connection between sending and destination hosts
  • Data stream also provides resources for (1) multiplexing upper-layer apps, (2) establishing virtual connection, (3) tearing down circuits
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the network layer do?

A
  • It manages logical device addressing
  • also tracks location of devices on the network
  • and determines the best way to move data
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the mechanism through which a network layer determines the best way to move data

A
  • when the router interface receives a packet, it checks the destination IP address
  • if destination IP does not equal router’s IP the router looks up destination network address in the address table and chooses the exit router interface
  • then, if a router is found, the router sends the packet through; else the router drops the packet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two types of data packets?

A
  1. Data packets

2. Route-update packets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do data packets do?

A

They transport user data through the internetwork using router protocols s.a. IPv4 and IPv6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do route-update packets do?

A

They update neighbor. routers connected to all routers within the internetwork using routing protocols (e.g. RIP, RIPv2, EIGRP, …)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are routing tables good for?

A

Each router maintains a routing table for individual routing protocols, because each protocol keeps track of networks with different addressing schemes (s.a. IP and IPv6)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does an interface represent in a router?

A
  • Each interface in a router represents a separate network and must be assigned a unique network ID
  • Each host on the network connected to the router must use the same network number
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a logical link control?

A
  • LLC identifies network layer protocols and encapsulates them; then it tells the data link layer what to do with a packet once a frame has been received
  • then the host determines what to do with a packet based on the LLC header
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is another name for routers?

A

Layer 3 switches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do routers treat domains?

A

Routers break up broadcast domains and collision domains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do routers never forward?

A
  • And router don’t forward broadcast domains!!

- Nor do they forward any multicast packets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do we know where to next forward a data packet?

A

We use a logical address in the network layer header to determine the next hop to which router forwards the data packet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do routers care about the most?

A

How to best reach a network!

24
Q

How do routers control security on the types of packets that are allowed to enter or exit the interface?

A

Routers can access lists created by an admin!

25
Q

What can routers connect?

A

Different LANs or VLANs

26
Q

What do routers provide?

A

QoS (quality of service) for specific types of network traffic

27
Q

Data Link - what does it do?

A

DL provides physical transmission of data and handles

  1. error notification,
  2. network topology,
  3. flow control
28
Q

What does data link ensure?

A

That messages are delivered to a proper device on LAN using MAC addresses

29
Q

What does Data link translate?

A

It translates messages from the network layer into bits for the physical layer

30
Q

How does data link format messages

A

Data link formats messages into pieces called data frames, then adds a customized header with source and destination hardware addresses

31
Q

What’s a MAC address?

A

a MAC defines how packets are placed on ?? ____

-> good for physical and hardware addressing

32
Q

What does the physical layer do?

A
  1. It sends bits.
  2. It receives bits.
  3. It helps to identify _______ (see another card)
  4. It specifies ________
33
Q

What does the physical layer help to identify?

A

It helps to identify the interface between DTE (data terminal equipment) and DCE (data communication equipment)

34
Q

What’s a CSU/DSU?

A

CSU/DSU is a channel service unit/data service unit (or a DCE device) through which the services available to DTE are accessed

35
Q

What does the physical layer specify?

A

It helps to specify the layout of transmission media = topology

36
Q

What layer does connection-oriented communication refer to?

A

transport!

37
Q

Name the four key components of connection-oriented communication

A
  1. virtual circuit
  2. sequencing
  3. 3-way handshake
  4. flow control
38
Q

What’s flow control?

A

It’s a means for the receiver to govern the amount of data sent by the sender

1) by ack’ing in 3-way handshake
2) by retransmitting any non-acknowledged segments
3) some segments are sequenced back into their proper order upon arrival at their destination
4) a manageable data flow is maintained to avoid congestion, overloading, and data loss

39
Q

3-way handshake in 3 steps?

A

1) first we request info syncing
2) then we acknowledge the request and establish connection params between hosts
3) then we notify the destination host that connection has been established

40
Q

What does a sender repeatedly do in a 3-way handshake?

A

A sender repeatedly acknowledges each segment it sends and waits for an ACK before sending the next one

41
Q

What’s a virtual circuit in connection-oriented communication?

A

VC is a connection established when a sender’s TCP contacts the destination’s TCP before a transmitting host starts to send segments down the model

1) two TCP processes agree on the amount of info that will be sent in either direction
2) recipient’s TCP sends back an acknowledgement

42
Q

What are datagrams?

A

That’s another name for packets, friend

43
Q

What happens if any of the datagrams are lost?

A

If any segments are lost, duplicated, or damaged, a failure notice is transmitted to the host

44
Q

What’s a window?

A

The quantity of data segments in bytes that the transmitting machine is allowed to send without receiving an acknowledgement

45
Q

What do windows control?

A

Windows control the amount of outstanding, unacknowledged data segments
- if a receiving host fails to receive all the segments that it should acknowledge, the host can improve the communication session by decreasing the window size

46
Q

Name my 4 devices that operate on all 7 layers of the OSI model

A
  1. Network mgmt stations
  2. Web and application servers
  3. Gateways
  4. Network hosts
47
Q

Name the 4 devices that operate primarily in the physical layer

A
  1. Network interface cards
  2. Transceivers
  3. Repeaters
  4. Hubs
48
Q

What are the essential units for communicating / exchanging info?

A

Protocol Data Units.

49
Q

Describe the communication in PDUs in terms of data encapsulation (5 steps)

A
  1. user info is converted into data for transmission on the network
  2. data is converted to segments and a reliable connection is set up between the transmitting and receiving hosts
  3. segments are converted to packets/ datagrams and a logical address is placed in the header so that each packet can be routed through an internetwork
  4. packets are converted into frames (with packets lol) for transmission on the local network. Hardware addresses uniquely identify hosts on a local network segment
  5. frames are converted to bits and a digital encoding and clocking scheme is used
50
Q

What’s modulation?

A

It’s a process of varying one or more properties of waveform with a signal that typically contains information to be transmitted

51
Q

What is a normal name of a modulator?

A

Modem, sir

52
Q

What does a modulator do?

A

A modulator takes a digital or analog signal and converts it into another kind of signal that can be physically transmitted

53
Q

Why do we need modulation?

A

To transfer a digital bit stream over an analog bandpass channel & vice versa

54
Q

What is frequency division multiplexing?

A

FDM is when several low-pass information signals are transferred simultaneously over the same shared physical network using separate passband channels

55
Q

What is a baseband channel?

A

It’s a channel where the signal being modulated is used for the complete available bandwidth

56
Q

What is Time-Division Multiplexing?

A
  • A method of transmitting and receiving many independent signals over a common signal path through synchronized network devices at each end of the transmission line s.t. each signal appears only a fraction of the time in an alternating pattern;
  • The receiving end demultiplexes signal back to original

Network+ (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions