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Flashcards in Block 7 Deck (95)
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0
Q

Data link layer addresses are also referred to as (4 others)

A

Physical, hardware machine or MAC address

1
Q

What defines how devices are addressed at the data link layer

A

Physical addressing

2
Q

What consists of the data link layer specifications that often define how devices are to be physically and logically connected?

A

Network topology

3
Q

Error detection uses CRC or FCS to detect errors in transmission. What layers are responsible for the actual error correction or request or request for transmission of a frame?

A

Higher layers

4
Q

What reorders frames that are received out of sequence?

A

Sequencing of data frames

5
Q

What moderates the transmission of data so that the receiving device is not overwhelmed with more than it can handle at one tim?

A

Flow control

6
Q

Switches primary method of flow control is?

A

Buffering

7
Q

What connects multiple network segments at the data link layer of the OSI model?

A

Bridge

8
Q

Layer 2 switching is very efficient because

A

No modification to packet
Only to frame encapsulation
And only when the data packet is passing through dissimilar media

9
Q

Bridges are ___________ based and switches are __________ based

A

Software

Hardware

10
Q

Bridges have a ________ spanning tree control and switches have a _________ spanning tree control

A

Limited

Advanced

11
Q

How many ports do switches have?

A

Hundreds

12
Q

How many ports do bridges have?

A

16

13
Q

A physical or logical network segment in which data packets can collide with each other

A

Collision domain

14
Q

__________ reduces the chances of this happening by preventing more than one device from accessing the Collision domain at the same time, but collisions can still occur.

A

Ethernet 802.3 CSMA/CD

15
Q

All network segments connected by layer 1 devices exist on a ___________ collision domain.

A

Single

16
Q

How many collision domains are on layer 2 devices ?

A

Each interface is a separate collision domain

17
Q

A logical network segment defined by its router port

A

Broadcast domain

18
Q

Devices physically connected to same media or layer 2 device will be on

A

Same broadcast domain

19
Q

What do switches use to build and maintain MAC address tables ?

A

Application-specific integrated circuits (ASICs)

20
Q

What do switches use to filter traffic?

A

MAC address from the host NIC

21
Q

Layer 2 switches provide ?

A

Hardware-based bridging
Wire speed
Low latency
Low cost

22
Q

Most common type of switches

A

Ethernet switches

23
Q

3 major functions of layer 2 switches

A

Address learning
Forward/filter decision
Loop advance

24
Q

3 methods of frame switching methods

A
Store and forward 
Cut through(real time)
Fragment free(modified cut-through)
25
Q

Where are the MAC address tables stored in the switches?

A

RAM

26
Q

Most switches hold up to how many MAC address in their table?

A

8000

27
Q

If a workstation does not talk for a period of time on the network chances are?

A

The MAC address has aged out (removed) from the table

28
Q

What helps I preserve bandwidth I other network segments?

A

Frame filtering

29
Q

In this Frame switching method the switch copies the entire frame into its buffers and computes the CRC.

*Best for error free but greatest amount of processing time?

A

Store-and-forward

30
Q

Also called real time, in this frame switching method the LAN switch only copies the destination address onto it’s on board buffers.

*reduces latency because no error checks but fastest method

A

Cut-through

31
Q

Also called modified cut-through, this frame switching method waits 64 bytes(collision window) to pass before forwarding.

*better error checking than cut-through mode with no increase in latency

A

Fragment free

32
Q

If a packet has an error it almost always occurs within the first __________.

A

64 bytes

33
Q

Why is it a good idea to use multiple (redundant) links between switches and multiple switches?

A

To avoid a single point of failure

34
Q

If loop avoidance schemes are not put in place, the switches will flood broadcasts endlessly throughout and internetwork.

A

Broadcast storms

35
Q

If a device receives multiple copies of the same frame because the frame can arrive from different segments at the same time what problem is occurring?

A

Multiple frame copies

36
Q

One of biggest problems generating through an internetwork where loops occur within loops

A

Multiple loops

37
Q

Use by layer 2 devices to stop network loops in networks that have more than one physical link to the same network

A

STP spanning tree protocol

38
Q

An external component that allows you local direct access to the switch during configuration

A

Console port

39
Q

And external component where you will connect your end devices such as your computers or printers.

A

Network interfaces

40
Q

And internal component where the diagnostics and boot up routines are stored. the contents of this type of memory cannot be changed since they are burned in the chip.

A

Rom

41
Q

Internal component that holds the Internet work operating system. this type of memory is similar to EEPROM.

A

Flash memory

42
Q

I’m going to start up operation the iOS is copied from the ______memory into ram for execution.

A

Flash

43
Q

This internal components type of memory is call nonvolatile memory. When Powers is removed from the switch the content of this memory will remain unchanged.
Used to store start -up config file

A

NVRAM

44
Q

This type of memory is called volatile memory. when power is removed from the switch the content of this memory will be lost.

A

Ram

45
Q

A logical grouping of network computers and resources connected to administratively defined ports on a layer 2 switch.

A

VLAN

46
Q

This is also called a broadcast domain and all connected devices see all broadcast packets that are transmitted.

A

Flat network

47
Q

What are VLAM benefits

A

(I)ncreased security
(N)o geographical barrier
(f)lexibility and scalability
(b)roadcast control

48
Q

What are the two types of the VLAN port membership assignments

A

Dynamic and static

49
Q

Which VLAN membership takes more work upfront but is easier to maintain

A

Dynamic VL AN

50
Q

Which VLAN membership requires less work initially but is more time-consuming for an admin to maintain

A

Static VLAN

51
Q

What are the two different link modes

A

Access link or trunk link

52
Q

What allows Cisco switches to automatically negotiate with other Cisco devices when they connect

A

Dynamic trunking protocol

53
Q

Switches without dynamic trunking protocol cannot negotiate and must be manually configured as

A

Access or truck link through static assignments

54
Q

A link that is assigned to one VLAN

A

Access link

55
Q

This link will carry traffic for all VLANs unless you specify otherwise

A

Trunk link

56
Q

What is the minimum speed for Trunk link

A

100 Mbps

57
Q

What are the two frame identification methods that Cisco supports

A

Inter-switch link (ISL)

IEEE 802.1q

58
Q

What uniquely assigns a user defined ID to each frame also call frame tagging

A

Frame identification

59
Q

VLAN frame identification places a ____________ in the header of each frame as it is forwarded through the switch fabric on Trunk links

A

Unique identifier

60
Q

Cisco proprietary protocol that is a way of encapsulating a VLAN frame with an added headed and trailer.

A

ISL inter-switch link protocol

61
Q

This process enables VLANs to be multiplexed over a trunk link through an external encapsulation method.

*external encapsulation method

A

ISL

62
Q

An open source standard method of frame tagging .

*internal tagging method

A

IEEE 802.1q

63
Q

A Cisco proprietary protocol that eases management of VLANs in an internetwork.

A

VLAN trunking protocol (VTP)

64
Q

Allows for creation, addition, deletion of control within an administrative domain .

A

VTP

65
Q

How many VTP domains do a switch belong to?

A

1

66
Q

A switch shares VLAN information with other switches in

A

The same domain

67
Q

What are the three modes a switch can operate in?

A

Server
Client
Transparent

68
Q

A central point(management) for VLAN creation within a domain

A

Server

69
Q

What mode receives information from a server and can forward received updates to other switches ?

A

Client

70
Q

This mode does not partake on VTP domain but can still receive and forward VTP advertisements through trunk links

A

Transparent

71
Q

What do VTP advertisements include?

A

Management domain name
Configuration revision #
VLANs
Parameters for each VLAN

72
Q

If a client receives an advertisement that has a higher revision #, what will happen

A

It will overwrite the database in NVRAM with the database being advertised

73
Q

If a switch was connected to another network it’s best to clear everything from its memory and then power-cycle it.
Reason?

A

So a high revision # will not overwrite the system

74
Q

What provides consistent network availability when an outrage occurs for one link?

A

Spanning-tree protocol (STP)

75
Q

A standardized protocol that provides a stable fault-tolerant loop free environment while selecting the fastest network path when redundant links exist with in a internetwork

A

STP

76
Q

Which algorithm chooses one path on which to forward frames and places the other redundant links in blocking state to stop any network loops from occuring

A

Spanning-tree algorithm

77
Q

What device will be the loop bridge?

A

The device with the lowest bridge ID

78
Q

All ports on the root bridge are called __________ and are set to _________

A

Designated ports

Forwarding “meaning they will pass data@

79
Q

After the root bridge is selected all other remaining switches become the ____________

A

Non-root bridge

80
Q

What is the main device that other switches in the network will “key on” to set their ports to forwarding or blocking to establish a path

A

Root bridge

81
Q

Later 2 devices with STP capability will exchange info using the ______________

A

Bridge protocol data units (BPDUs)

82
Q

How many bytes is the bridge iD and what does it include

A

8 bytes and includes the default priority plus the MAC of the device

83
Q

The default priority for all devices running the IEEE version of STP is?

A

32768

84
Q

Root ports are in _______ mode and provide a constant connection to the root bridge from the non root bridge so advertisements and updates are received.

A

Forwarding

85
Q

These ports are used to prevent loops. after a switch has determine the best path to the bridge all other ports are placed in the blocking state

A

Non designated port (blocked)

86
Q

This occurs when bridges and switches have completed the transitions to either the forwarding or blocking state

A

Convergence

87
Q

How long can convergence take up to

A

50 secs

88
Q

How much data is forwarded doing convergence

A

None

89
Q

By default what runs on all switch ports

A

Spanning tree protocol

90
Q

whenever a New port is enable spanning tree goes through the following port states to get that port to be either forwarding or blocking

A

Blocking- will not forward frames
Listening- listens to make sure no loops before pass in frames
Learning -learns Mac addresses and builds tables
Forwarding- bridge port able to send and receive data …a port will never be placed in forward state unless there are no redundant links

91
Q

What is use to speed up convergence on ports that are connected to workstations and servers or other devices that will not cause layer 2 loops

A

Spanning tree portfast

92
Q

What are the three spanning tree protocol standards

A

CST common spanning tree
PVST Per-VLAN spanning tree
PVST + Per VLAN spanning Tree +

93
Q

Also called mono spanning tree because it uses only one spanning tree instance regardless of the size of the later 2 networks or number of VLANs

A

CST common spamming trees

94
Q

Cisco proprietary, uses ISL and runs a separate instance for each VLAN.

Smaller STP implementation and easier convergence

A

Per-VLAN spanning tree (PVST)