Brainscape's Knowledge GenomeTM

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


See full index

Cisco ICND 2 > Section 2 > Flashcards

Section 2 Flashcards

Building Redundant Switched Topologies

1
Q

What does STP stand for?

A

Spanning Tree Protocol

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

What algorithm does STP use?

A

The Spanning Tree Algorithm

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

What is the purpose of STP in a network.

A

To prevent Layer 2 loops

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

What messages does STP use to pass information between bridges?

A

BPDUs (Bridge Protocol Data Units)

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

What is the most common STP standard used by network devices?

A

IEEE 802.1D

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

What is the IEEE 802.1 standard based on?

A

The Digital Equipment Corporation STP

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

What does LAN stand for?

A

Local-Area Network

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

What is a LAN?

A

A high-speed, low error data network covering a relatively small geographic area (office or campus).

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

What do LAN standards specify?

A

Cabling and signaling at the Physical and Data Link layers of the OSI model.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are three examples of LAN technologies?

A

Ethernet, FDDI, and Token Ring.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does MAC address stand for?

A

Media Access Control address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a MAC address?

A

A standardized data link layer address that is required for every port or device that connects to a LAN.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do other devices use the MAC address for?

A

To locate specific ports, create, and update routing tables and data structures.

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

How many bits/bytes is a MAC address?

A

48 bits (6 bytes)

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

What other terms are commonly used to refer to a MAC address?

A

Hardware address, MAC layer address, and physical address.

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

Why does STP place ports into a Standby state?

A

To ensure they do not listen to, forward, or flood data frames.

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

What is the effect of STP placing ports into a standby state?

A

It ensures there is only one path that is active to each network segment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does STP do if there is a problem with connectivity to a segment?

A

Re-establish connectivity by automatically activating a previously inactive path, if one exist.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Ethernet?

A

A baseband LAN specification invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation.

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

What collision avoidance mechanism does Ethernet use?

A

CSMA/CD

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

What speed do Ethernet networks run at?

A

10 Mbps

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

What is the most commonly used LAN technology?

A

Ethernet

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

Ethernet is similar to which IEEE standard(s)?

A

802.3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why is Ethernet one the most commonly used LAN technology?

A

It is easy to implement, manage, and maintain. It allows low cost network implementations, provides topological flexibility, and is standards compliant (manufacturer independent).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why are redundant topologies important?

A

They eliminate a single point of failure in the network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What issues can occur in a redundant topology without a loop prevention mechanism?

A

Broadcast storms, multiple frame copies, MAC address table instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What occurs during a broadcast storm?

A

The switch floods broadcast endlessly due to a layer 2 loop.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Why are multiple frame copies arriving at a destination an issue?

A

Many protocols expect to only receive one copy. Multiple copies of the same frame can cause unrecoverable errors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What causes MAC database (address table) instability?

A

Different interfaces on the switch receive copies of the same frame.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What issue is the result of MAC database instability?

A

Data forwarding can be impaired due to too much resource usage coping with the constant changes in the MAC address table.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does TTL stand for?

A

Time to Live

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is TTL?

A

A mechanism that limits the lifespan or lifetime of data in a computer network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

At what OSI layer do protocols commonly make use of TTL?

A

Layer 3 (Network Layer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Do OSI Layer 2 protocols make use of TTL?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What does IEEE (I triple E) stand for?

A

Institute of Electrical and Electronics Engineers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why is the IEEE important in regards to networking?

A

It is a professional organization whose activities include the development of communications and network standards.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the MAC Bridges standard?

A

IEEE 802.1D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does the IEEE 802.1D standard specify?

A

The MAC bridges standard, which includes bridging and spanning tree, among others.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Who standardizes IEEE 802.1D?

A

The IEEE 802.1 working group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How does STP provide a loop free topology?

A

By placing certain ports into the blocking state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Where are STP standards published?

A

In the 802.1D specification.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What does STP use for communication between switches?

A

BPDUs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why does STP place certain ports into a blocked state?

A

So they do not listen to, forward, or flood data frames.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How many paths should exist to each segment when STP is active?

A

One

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What does BPDU stand for?

A

Bridge Protocol Data Unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is a BPDU?

A

A Spanning Tree Protocol hello packet that is sent out at configurable intervals to exchange information among bridges in the network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

How many fields compose a BPDU bridge ID? What are they?

A

Two. The Bridge Priority and MAC address.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How many bytes are the Bridge Priority and MAC address fields in a BPDU Bridge ID?

A

Bridge Priority (2 bytes) MAC address field (6 bytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What four steps does the STP alogrithm follow?

A
  1. Elects a root bridge
  2. Elects a root port for each non-root switch
  3. Elects a designated port for each segment
  4. Ports transition to a forwarding or blocking state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is the value range for the Bridge Priority?

A

0 - 65,535

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the default value for the Bridge Priority field?

A

32,768

52
Q

What increment can the Bridge Priority value be changed by?

A

4096

53
Q

Which bridge is elected the root bridge?

A

The one with the lowest Bridge ID

54
Q

How many root bridges can there be per network?

A

One

55
Q

What occurs if two bridges have the same lowest bridge priority?

A

The one with lowest MAC address will become the root bridge.

56
Q

What is a root port?

A

The switch port with the best path to the root bridge.

57
Q

How many root ports can exist on a switch?

A

One

58
Q

Does the root bridge contain any root ports?

A

No

59
Q

Designated ports are chosen based on what?

A

The lowest root path cost.

60
Q

Each STP link must contain one port of which type.

A

Designated

61
Q

If a port does not become a root or designated port, what state will it be placed into?

A

Blocking

62
Q

What does BID stand for in relation to STP?

A

Bridge ID

63
Q

What are the four STP port roles?

A
  1. Root
  2. Designated
  3. Non-Designated (blocking in STP, discarding in RSTP)
  4. Disabled
64
Q

What is the STP path cost for a 4 Mbps link?

A

250 (old), 5,000,000 (new)

65
Q

What is the STP path cost for a 10 Mbps link?

A

100 (old), 2,000,000 (new)

66
Q

What is the STP path cost for a 16 Mbps link?

A

62 (old), 1,250,000 (new)

67
Q

What is the STP path cost for a 100 Mbps link?

A

19 (old), 200,000 (new)

68
Q

What is the STP path cost for a 1 Gbps link?

A

4 (old), 20,000 (new)

69
Q

What is the STP path cost for a 2 Gbps link?

A

3 (old), 10,000 (new)

70
Q

What is the STP path cost for a 10 Gbps link?

A

2 (old), 2,000 (new)

71
Q

Which switch is elected root bridge?

A

The switch with the lowest bridge ID.

72
Q

What root ID does a switch start with?

A

Its own root ID.

73
Q

When does a switch replace its root ID with the ID from another switch?

A

When it receives a BPDU indicating that another switch has a lower root ID.

74
Q

What is the difference between the Root ID field and the Bridge ID field?

A

The Root ID field contains the Bridge ID value of the current root bridge. The Bridge ID field will contain the Bridge ID of the switch sending the BPDU.

75
Q

What field in a BPDU packet indicated the root bridge?

A

The Root ID field.

76
Q

How is root path cost determined?

A

Based on link speed. The higher the bandwidth, the lower the cost.

77
Q

How are ties broken for Designated ports?

A

Ties are broken based off upstream bridge ID and then lowest port ID if necessary.

78
Q

What state do ports start in at the beginning of the STP algorithm.

A

Blocking

79
Q

What does CST stand for?

A

Common Spanning Tree

80
Q

What is CST?

A

A single spanning-tree instance regardless of the number of VLANs.

81
Q

What does PVST+ stand for?

A

Per VLAN Spanning Tree Plus

82
Q

What is PVST+

A

A Cisco proprietary enhancement of STP that provides a separate 802.1D spanning-tree instance for each VLAN that is configured on the network.

83
Q

What does MSTP stand for?

A

Multiple Spanning Tree Protocol

84
Q

What is MSTP.

A

An IEEE standard that is inspired by the earlier Cisco proprietary MISTP implmentation. MSTP maps multiple VLANs into the same spanning-tree instance.

85
Q

What does MISTP (“myst-p”) stand for?

A

Multi-Instance Spanning Tree Protocol

86
Q

What does RSTP stand for?

A

Rapid Spanning Tree Protocol

87
Q

What is RSTP?

A

An evolution of STP that provides faster convergence of STP. It redefines port roles and link cost.

88
Q

What doest Rapid PVST+ stand for?

A

Rapid Per-VLAN Spanning Tree Plus

89
Q

What is Rapid PVST+?

A

A Cisco enhancement of RSTP that uses PVST+. Rapid PVST+ provides a separate instance of 802.1w per VLAN.

90
Q

List the following for STP: standard, resources needed, convergence time speed (slow or fast), number of spanning trees.

A

802.1d, low, slow (30 seconds), one

91
Q

List the following for PVST+: standard, resources needed (low, medium, or high), convergence time speed (slow or fast), number of spanning trees.

A

Cisco proprietary, high, slow, one per VLAN

92
Q

List the following for RSTP: standard, resources needed, convergence time speed (slow or fast), number of spanning trees.

A

802.1w, medium, fast, one

93
Q

List the following for Rapid PVS+: standard, resources needed, convergence time speed (slow or fast), number of spanning trees.

A

Cisco proprietary, high, fast, one per VLAN

94
Q

List the following for MSTP: standard, resources needed, convergence time speed (slow or fast), number of spanning trees.

A

802.1s, medium OR high, fast, one for multiple (groups of) VLANs

95
Q

What is the default Spanning Tree configuration for Cisco switches?

A

PVST+

96
Q

What is the main advantage of PVST+

A

Load balancing can occur since STP is determined per VLAN.

97
Q

What is the main disadvantage of PVST+

A

It is resource intensive due to having to calculate the spanning-tree for each VLAN.

98
Q

What does PVST+ modify to keep STP data separate for each VLAN.

A

The Bridge ID is modified to the Extended Bridge ID in order to contain the VLAN ID.

99
Q

What fields does the Extended Bridge ID contain?

A

Bridge Priority (4 bits), Extended System ID (12 bits), and the MAC address (48 bits). Extended Bridge ID is still 64 bits (8 bytes) total.

100
Q

What command is used to force a switch to be the root bridge for a specified VLAN?

A

spanning-tree vlan root primary

101
Q

What does the following command accomplish?

spanning-tree vlan root primary

A

It forces the switch to be the root bridge for a specified VLAN.

102
Q

What command configures a switch to be the backup root bridge for a specified VLAN?

A

spanning-tree vlan root secondary

103
Q

What command is used to view spanning-tree configuration for manually set root bridges?

A

show running-config | include root

104
Q

What command displays an overview of STP status and topology?

A

show spanning-tree

105
Q

What does the following command accomplish?

show spanning-tree

A

It displays an overview of STP status and topology

106
Q

Which command is used to obtain STP information for a particular VLAN?

A

show spanning-tree vlan

107
Q

What are the STP port stages?

A
  1. Blocking
  2. Listening
  3. Learning
  4. Forwarding
108
Q

What is the maximum time a port spends in the Blocking state?

A

20 seconds

109
Q

What is the maximum time a port spends in the Listening state?

A

15 seconds

110
Q

What is the maximum time a port spends in the Learning state?

A

15 seconds

111
Q

Does a port in the Listening state populate the MAC address table? Does it forward frames?

A

No. No.

112
Q

Does a port in the Learning state populate the MAC address table? Does it forward frames?

A

Yes. No.

113
Q

Does a port in the Forwarding state populate the MAC address table? Does it forward frames?

A

Yes. Yes.

114
Q

What does DHCP stand for?

A

Dynamic Host Configuration Protocol

115
Q

What is DHCP used for?

A

It provides a mechanism for allocating IP address dynamically so that addresses can be reused when the host no longer needs them.

116
Q

What is PortFast?

A

An STP feature that can be enabled on access ports so that they instantly enter the forwarding state.

117
Q

Where should PortFast be configured?

A

On access ports only.

118
Q

What is the purpose of BPDU Guard?

A

BPDU Guard will shut down a port if it receives a BPDU.

119
Q

What is BPDU Guard typically used in conjunction with?

A

PortFast

120
Q

Where should BPDU guard be configured?

A

On access ports only

121
Q

What command activates PortFast on an interface?

A

spanning-tree portfast

122
Q

What command activates PortFast globally on a switch?

A

spanning-tree portfast default

123
Q

What command activates BPDU Guard on an interface?

A

spanning-tree bpduguard enable

124
Q

What command activates BPDU Guard globally?

A

spanning-tree portfast bpdguard default

125
Q

What command indicates whether PortFast and BPDU Guard have been configured on an interface?

A

show running-config interface [interface]

126
Q

What command indicates whether PortFast has been configured on a port or globally?

A

show spanning-tree interface [interface] portfast

127
Q

What command indicates whether PortFast and BPDU Guard have been enabled globally?

A

show spanning-tree summary

Cisco ICND 2 (4 decks)

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