8 - Advanced Switching Concepts Flashcards

1
Q

What is a LAN?

A

a set of devices in a single broadcast domain

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2
Q

What are some benefits of VLANs?

A
  1. reduce the number of broadcast domains
  2. increase security because traffic is not seen by another vlan unless its routed
  3. qos can be maintained for each vlan
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3
Q

What is the routing of packets between VLANs

A

intervlan routing

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4
Q

Why should subnets used by vlans on your network be contiguous?

A

to facilitate route summarization

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5
Q

What are valid vlan ids?

A

1 - 4094

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6
Q

What vlan ids are reserved?

A

0 hidden system use
1002 - 1005 token ring and fiber distributed data interface
4095 hidden system use

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7
Q

What command can be used to show a brief summary of vlans on a switch?

A

show vlan brief

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8
Q

What type of port carries traffic for only one vlan?

A

access port

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9
Q

what command is used to set the access vlan back to its default?

A

no switchport access vlan

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10
Q

What is the command to dynamically map mac addresses to a vlan?

A

switchport access vlan dynamic

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11
Q

What type of port carries traffic from multiple vlans?

A

trunk port

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12
Q

What are the two trunk encapsulation types?

A

ISL or inter switch link

802.1q

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13
Q

How do you identify the vlan that a frame belongs to/

A

a tag

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14
Q

Describe ISL encapsulation.

A

cisco proprietary ecapsulation that encapsulates each from inside of a 26 byte ISL header and 4 byte crc trailer

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15
Q

Describe 802.1q encapsulation.

A

standards based trunking protocol developed by IEEE that inserts a 4 byte vlan field into the frames existing ethernet header

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16
Q

What encapsulation method has support for a native vlan?

A

802.1q

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17
Q

What is the outcome for a native vlan mismatch?

A

traffic sent to an incorrect vlan

cdp errors

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18
Q

What needs to match on both sides of a trunk link?

A

native vlan
trunking mode
trunk encapsulation
allowed vlan ids for the trunk

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19
Q

What command is useful in providing a variety of helpful output for both access and trunk ports?

A

show interfaces fa0/0 switchport

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20
Q

What command is useful in verifying trunk ports?

A

show interfaces fa0/0 trunk

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21
Q

What is useful about the show interfaces fa0/0 trunk command?

A

you can see the allowed vlans for a trunk

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22
Q

Why is voice traffic usually separated from data traffic?

A

for performance purposes

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23
Q

What happens when the voice vlan is configured on a port?

A

portfast is automatically enabled

24
Q

how do you enable qos on the voice vlan?

A

trust device cisco-phone

25
Q

What is the limitation for port-security on a voice vlan?

A

You cannot statically configure mac addresses on a voice port, you have to use the maximum 2 command at a minimum

26
Q

What command causes the ip phone to use 802.1p tagging with a priority of 5 instead of 802.1q causing it to transit over the native vlan?

A

switchport voice vlan dot1p

27
Q

What command causes the ip phone to behave as if it were not connected to a switch, using its own config and traversing the access vlan?

A

switchport voice vlan none

28
Q

What command causes the ip phone to send untagged voice traffic just as if the switchport voice vlan command was not used?

A

switchport voice vlan untagged

29
Q

How do you disable DTP?

A

switchport nonegoiate

30
Q

What is ciscos recommendation for trunk links?

A

set both sides of the trunk to dynamic desirable when using DTP

31
Q

What are different modes of a switchport?

A

access
trunk
dynamic desirable
dynamic auto

32
Q

What is dynamic desirable?

A

a port that will actively negotiate to become a trunk port

33
Q

What is dynamic auto?

A

a port that will no actively negotiate to become a trunk port

34
Q

What is the outcome if you have two switchports that are configured for dynamic auto?

A

they will be access ports and not trunk ports

35
Q

What is the outcome if you have two switchport that are configured for dynamic deseriable?

A

they will be trunk ports

36
Q

What is the outcome if you have one switchport as dynamic auto and one switchport as dynamic desirable?

A

they will be trunk ports

37
Q

What layer does vtp operate at?

A

Layer 2

38
Q

What are the requirements for VTP to operate?

A

switches must be connected over a trunk
vtp domain must match
vtp password must match
vtp version must match

39
Q

what is the default vtp domain name?

A

NULL

40
Q

how many vtp domains can a switch belong to?

A

one

41
Q

What happens to a switch that is configured for the NULL domain receives a vtp advertisement with a different vtp domain name?

A

it will change its vtp domain to match

42
Q

What vtp version is configured by default?

A

vtp version 1

43
Q

What happens if a vtp version 1 switch receives a vtp version 2 advertisement?

A

the switch will change to version 2 if it is supported on that swithc

44
Q

What is the default vtp mode of cisco switches?

A

server mode

45
Q

Where do vtp version 3 clients store their vlan configuration?

A

NVRAM, vtp version 1 and 2 clients do not keep the vlan configuraton

46
Q

What does vtp transparent mode do?

A

Transparent mode will forward vtp advertisements, but not update its own vlan table. Transparent mode keeps its local vlan configuration in nvram

47
Q

How often do vtp servers and clients flood their advertisements?

A

every 5 minutes or when a change is made

48
Q

What vlan is used for vtp advertisements?

A

vlan 1

49
Q

How do switches keep track of the changes to the vlan database?

A

incrementing the configuration revision number

50
Q

Can a vtp client cause a vtp server to be updated?

A

Yes, if the clients revision number is higher than the servers revision number

51
Q

What is the revision number of a vtp transparent switch?

A

revision 0

52
Q

How do you delete the vlans on a switch?

A

deleting the vlan.dat from flash or nvram

53
Q

what is vtp pruning?

A

prunes vlan traffic to switches that are not participating in a particular vlan

54
Q

Is vtp pruning enabled by default?

A

its disabled by default

55
Q

How do you configure vtp pruning?

A

global configuration mode, vtp pruning

56
Q

How can you have intervlan routing when you only have layer 2 switches?

A

using router on a stick