CCNP switch slides 2 Flashcards

1
Q

Source

A

http://quizlet.com/3373135/ccnp-switch-deck-2-flash-cards/

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2
Q

How many links can be used in an EtherChannel?

A

2-8 FE, GE, or 10GE are bundled.

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3
Q

What types of link can an etherchannel be?

A

access or trunk

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4
Q

What are the restrictions for bundling into an Etherchannel?

A

must be same type, speed, VLAN(s), native vlan, pass the same set of vlans,duplex, and spanning tree settings

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5
Q

How are frames forwarded across a specific link?

A

hashing algorithm

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6
Q

What can the Etherchannel hash use?

A

source IP, dest IP, combination of source and dest IP, source and dest MAC, or TCP/UDP port numbers

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7
Q

What are the port channel load balancing methods?

A

src-ip, dst-ip, src-dst-ip, src-mac, dst-mac, src-dst-mac, src-port, dst-port, src-dst-port

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8
Q

What is the default mode of load balancing?

A

src-dst-ip

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9
Q

What are the two etherchannel negotiation protocols?

A

PAgP (Cisco proprietary) and LACP (standards-based)

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10
Q

What are the PAgP negotiation modes

A

on (all ports channel), auto (channels when asked), and desirable(actively asks to form a channel)

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11
Q

How does PAgP form etherchannels?

A

only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified

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12
Q

What is a LACP priority?

A

the priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)

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13
Q

How many potential links can LACP define?

A

16, of which up to 8 are active. The others are in standby

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14
Q

what is the range of PAgP channel group numbers?

A

1 to 64

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15
Q

By default, what submode does PAgP operate in with the desirable and auto modes?

A

silent

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16
Q

what should you do if you expect a PAgP capable switch at the other end vs. a server or host?

A

configure non-silent submode

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17
Q

What are the steps to configure a PAgP port channel?

A

1-(opt) configure load balancing, 2-select the interface(s), 3-assign the protocol, 4-select the mode and submode

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18
Q

What is the LACP priority range?

A

1-65535 (def 32768) lower priority, higher probability

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19
Q

How do you configure LACP standby links?

A

LACP port priority

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20
Q

What are the steps to configure a LACP port channel?

A

1-(opt) set system priority, 2-select interface(s), 3-assign the protocol, 4-set the mode, 5-(opt) set the port priority

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21
Q

If one end of an Etherchannel (either type) is set to on and the channel doesn’t form, what should you check?

A

Both ends should be on because on modes doesn’t send PAgP or LACP packets

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22
Q

What must the other end be set to if PAgP desirable or LACP active mode is selected?

A

either desirable or auto mode

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23
Q

Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?

A

no because they only participate if asked

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24
Q

What is the IEEE standard for STP?

A

802.1D

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25
Q

How are BPDUs spread?

A

multicast to 01-80-c2-00-00-00

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26
Q

What are the 2 types of BPDU?

A

configuration and TCN

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27
Q

How often are BPDUs sent?

A

2 seconds (def)

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28
Q

What is a bridge ID made up of?

A

bridge priority and MAC

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29
Q

What is the bridge priority range?

A

0-65535 (def 32768) lower=better

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30
Q

In a converged fabric, which switch(es) send config BPDUs?

A

root

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31
Q

How is root port decided upon?

A

lowest cumulative cost to root

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32
Q

What is the cost of a 10 Mbps link?

A

100

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33
Q

What is the cost of a 100Mbps link?

A

19

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34
Q

What is the cost of a 1Gbps link?

A

4

35
Q

What is the cost of a 10Gbps link?

A

2

36
Q

How many designated ports are there?

A

1 per segment

37
Q

If there are 2 ports with same root cost, how is the tie broken for designated port?

A

1-lowest root bridge ID, 2-lowest root path cost, 3-lowest bridgeID, 4-lowest port ID

38
Q

What are the 5 STP states?

A

disabled, blocking, listening, learning, forwarding

39
Q

What is the STP disabled state?

A

admin down

40
Q

What is the STP blocking state?

A

Can hear only BPDUs

41
Q

what is the STP listening state?

A

can send and receive BPDUs

42
Q

What is the STP learning state?

A

after forwarding delay, port can learn new MAC addresses

43
Q

What is the STP forwarding state?

A

after another forwarding delay, the port can send and receive data frames, collect MAC addresses, and send and receove BPDUs

44
Q

What are the 5 steps to manualy configure STP?

A

1-ID link path costs, 2-ID roodt bridge, 3-select root port (1/switch), 4-select designated port (1/segment), 5-ID blocking port

45
Q

What is the STP hello timer?

A

Time between BPDUs sent by root bridge. Default of 2 seconds

46
Q

What is the STP forward delay timer?

A

The time that a port spends in both listening and learning states . Default 15 seconds

47
Q

What is the STP Max Age timer?

A

The time interval that a switch stores a BPDU before discarding it. Default 20 seconds

48
Q

What is the default network diameter?

A

7 switches from root bridge

49
Q

Where should you change the network diameter value?

A

Cisco recommends only on the root bridge

50
Q

What is a topology change?

A

When a port moves into forwarding or from fowarding or learning to blocking.

51
Q

What happens when the topology changes?

A

A TCN BPDU is sent out of the switch’s root port. The switch will continue sending TCN’s every hello interval until ack’d by upstream neighbor. The root bridge will send a Config BPDU to all switches

52
Q

What happens when switches receive a configuration BPDU?

A

They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)

53
Q

What is a direct topology change?

A

One that can be detected on a switch interface (ie. Up/down)

54
Q

What is an indirect topology change?

A

The link status stays up, but something between them has failed or is filtering traffic

55
Q

What is an insignificant topology change?

A

A host port goes up or down

56
Q

What is common spanning tree (CST)?

A

Single instance of STP for all VLANs. BPDUs are sent over trunks using the native VLAN with untagged frames. Dot1q based

57
Q

What is Per VLAN STP (PVST)?

A

Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q

58
Q

What is PVST plus (PVST+)?

A

allows devices to interoperate with PVST and CST. Can use both dot1q and ISL

59
Q

What is the port ID?

A

16 bits (8b port priority, 8b port number)

60
Q

what is the port number range?

A

0-255

61
Q

what is the port priority range?

A

0-255 (lower is better)

62
Q

Where should STP timers be configured and why?

A

on root, because the root bridge propagates timers with config BPDU

63
Q

How do you automatically configure STP timers

A

use the spanning-tree root macro

64
Q

What is portfast?

A

almost eliminates listening and learning states for single hosts on an access link

65
Q

What does the switchport host macro do?

A

enables portfast, sets the port to access and disables PAgP

66
Q

What does uplinkfast do?

A

enables switches at the end of the spanning tree branches to have a functioning root port while keeping 1 or more redundant potential ports in blocking mode. When the main fails, the other comes up.

67
Q

What are the gotchas for uplinkfast?

A

should be used on access switches, can’t be used on root, keeps enabled switch from becoming root by raising priority of switch and all ports, making them undesirable

68
Q

How does uplinkfast handle changes in topology?

A

notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.

69
Q

What is backbonefast?

A

causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure

70
Q

How does backbonefast determine whether alternative paths exist?

A

1- inferior BPDU on blocked-considered alternative, 2-inferior on root-all blocked ports considered alternate, 3-if inferior arrives on root and no blocked ports, assumes loss of connectivity to root

71
Q

What is a root link query (RLQ)?

A

backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge

72
Q

How does backbonefast work?

A

by short-circuiting the max age timer

73
Q

How should backbonefast be configured?

A

on all switches in network to enable RLQ request and reply

74
Q

When are new path costs from BPDUs computed on a switch?

A

when the BPDU comes IN the switch.

75
Q

When is the UplinkFast command not allowed?

A

On the root bridge switch.

76
Q

What are the 5 STP port states?

A

Disabled-Blocking-Listening-Learning-Forwarding

77
Q

What is the STP Max Age timer?

A

The time that a switch stores a BPDU before discarding it. Default is 20 seconds. Range is 6-40

78
Q

Define STP PVST.

A

Per-VLAN Spanning Tree. Cisco Proprietary, and operates a separate instance of STP on each VLAN. Requires ISL encapsulation between switches. PVST and CST cannot easily coexist.

79
Q

How many root ports can a single switch have?

A

Only ONE, that always points towards the root bridge!

80
Q

If a switch has BackboneFast and any blocked ports, what does it use to figure out alternate paths?

A

The Root Link Query (RLQ) protocol.

81
Q

What is the STP path cost of 10G, 1G, 622M, 155M, 100M, and 10M?

A

2, 4, 6, 14, 19, and 100

82
Q

What is the value range and default value of STP port priority?

A

0-255, and defaults to 128.

83
Q

When should you use STP PortFast?

A

Only from access layer switches to workstations.