STP Flashcards
1
Q
Classic spanning tree IEEE standard
A
802.1D
2
Q
Root bridge election process
A
Switch with lowest Bridge ID
3
Q
Default bridge priority (not including extended system Id)
A
32768
4
Q
Bridge ID structure
A
Bridge priority - 4 bits
Extended system ID - 12 bits
MAC address - 48 bits
5
Q
STP bridge priority can be changed in units of
A
4096
6
Q
802.1D 10mbps cost
A
100
7
Q
802.1D speed for cost of 100
A
10mbps
8
Q
802.1D 100Mbps cost
A
19
9
Q
802.1D 19 cost speed
A
100Mbps
10
Q
802.1D 1 Gbps cost
A
4
11
Q
802.1D 4 cost speed
A
1gbps
12
Q
802.1D 10gbps cost
A
2
13
Q
802.1D 2 cost speed
A
10gbps
14
Q
STP root port selection
A
- Lowest Root cost
- Lowest neighbor bridge ID
- Lowest neighbor port ID
15
Q
STP default forward delay timer
A
15 seconds
16
Q
STP default hello timer
A
2 seconds
17
Q
STP default max age timer
A
20 seconds (10*hello timer)
18
Q
PVST+ BPDUs are sent to destination MAC address:
A
0100.0ccc.cccd
19
Q
Standard STP (NOT PVST) BPDUs are sent to destination MAC address:
A
0180.c200.0000
20
Q
spanning-treee vlan vlan-id root primary sets the STP priority to […], or 4096 less than the current root’s priority.
A
24576
21
Q
spanning-tree vlan vlan-id root secondary sets the STP priority to […]
A
28672
22
Q
Rapid STP is IEEE […]
A
802.1w
23
Q
Multiple STP is IEEE […]
A
802.1s
24
Q
What is the protocol version identifier in a rapid STP BPDU?
A
2
25
What is the protocol version identifier in a classic STP BPDU?
0
26
In RSTP, a switch considers a neighbor lost if it misses [...] BPDUs.
3
27
STP Non-Designated ports are in a [...] state
blocking
28
STP Root ports are in a [...] state.
forwarding
29
STP: There must be one [...] port per collision domain.
designated
30
STP: There must be one designated port per [...].
collision domain
31
In an 802.1D STP network, which switch(es) send BPDUs?
Root bridge only
32
STP: When a switch is powered on, it assumes the role of [...] bridge.
root
33
STP Designated ports are in a [...] state.
forwarding
34
STP: All ports on the root bridge are [...] ports (forwarding state)
designated
35
STP: The switch with the lowest [...] becomes the root bridge.
Bridge ID
36
Which field in the STP BPDU is used to elect the root bridge?
Bridge ID field
37
How many root bridges are elected in STP?
One
38
What does BPDU stand for?
Bridge Protocol Data Unit
39
The messages sent by STP switches are called:
BPDUs (Bridge Protocol Data Units)
40
Do all switches run STP by default?
Yes
41
When a switch rapidly and continuously updates a MAC address in its MAC address table, alternating between different interfaces, this is known as [...]
MAC address flapping
42
If looped Layer 2 broadcast messages accumulate and congest a network, this is called a [...]
broadcast storm
43
Configure the STP priority of an interface:
SW1(config-if)# [...]
spanning-tree vlan vlan-id port-priority priority
44
Configure the STP cost of an interface:
SW1(config-if)# [...]
spanning-tree vlan vlan-id cost cost
45
Configure the spanning-tree secondary root for a VLAN:
SW1(config)# [...]
spanning-tree vlan vlan-id root secondary
46
Configure the spanning-tree root for a VLAN:
SW1(config)# [...]
spanning-tree vlan vlan-id root primary
47
Configure spanning tree in PVST mode:
SW1(config)# [...]
spanning-tree mode pvst
48
Which STP optional feature shuts down an interface if it stops receiving BPDUs?
Loop Guard
49
Which STP optional feature prevents a newly connected switch from becoming the root bridge?
Root Guard
50
Enable BPDU Guard on all Portfast-enabled interfaces:
SW1(config)# [...]
spanning-tree portfast bpduguard default
51
Enable BPDU Guard on a switch port:
SW1(config-if)# [...]
spanning-tree bpduguard enable
52
SW1(config)# spanning-tree portfast default
This command enables portfast on which ports?
All access ports
53
Enable portfast on all access ports on the switch:
SW1(config)# [...]
spanning-tree portfast default
54
Enable portfast on a switch port:
SW1(config-if)# [...]
spanning-tree portfast
55
If an interface with [...] enabled receives a BPDU from another switch, the interface will be shut down.
BPDU Guard
56
[...] allows an STP port to move immediately to the forwarding state.
Portfast
57
The STP timers on the [...] determine the timers used for all switches in the network.
root bridge
58
STP: A blocking interface [can/can't] move directly to a forwarding state.
can't
59
STP: A forwarding interface [can/can't] move directly to a blocking state.
can
60
STP BPDUs are only forwarded on [...] ports.
designated
61
STP default max age timer:
20 seconds (10*hello timer)
62
STP default hello timer:
2 seconds
63
STP: Do interfaces in a Forwarding state learn MAC addresses?
Yes
64
STP: Do interfaces in a Forwarding state send/receive BPDUs?
Yes
65
STP: Do interfaces in a Forwarding state send/receive regular network traffic?
Yes
66
STP: Do interfaces in a Learning state learn MAC addresses?
Yes
67
STP: Do interfaces in a Learning state send/receive BPDUs?
Yes
68
STP: Do interfaces in a Learning state send/receive regular network traffic?
No
69
STP: Do interfaces in a Listening state learn MAC addresses?
No
70
STP: Do interfaces in a Listening state send/receive BPDUs?
Yes
71
STP: Do interfaces in a Listening state send/receive regular network traffic?
No
72
STP default Forward delay timer:
15 seconds
73
STP: Do interfaces in a blocking state learn MAC addresses?
No
74
STP: Do interfaces in a blocking state receive BPDUs?
Yes
75
STP: Do interfaces in a blocking state send BPDUs?
No
76
STP: Do interfaces in a blocking state send/receive regular network traffic?
No
77
STP: Non-designated ports are in a [...] state.
Blocking
78
What are the two 'transitional' STP port states?
Listening, Learning
79
What are the two 'stable' STP port states?
Blocking, Forwarding
