Multiple Spanning Tree Protocol

Question 1

How many instances does standard STP 802.1D support?

What is 802.1D referred to?

In 802.1D do all VLAN’s use the same topology?

Answer 1

Single Instance for entire switch

(CST) Common Spanning Tree

Question 2

In 802.1D do all VLAN’s use the same topology?

Answer 2

no

Question 3

What is (MST) Multiple Spanning Tree capable of?

Answer 3

mapping one or multiple VLANs onto a single PVST STP tree called MST Instance (MSTI)

Question 4

What is an MST Region?

Answer 4

grouping of MST switches with the same configuration

Question 5

MST uses a special STP instance that’s called what?

Answer 5

(IST) Internal Spanning Tree

Question 6

Where does (IST) Internal Spanning Tree operate?

Answer 6

all switch ports interfaces for switches in the MST region, regardless of VLAN’s associated with the ports.

Question 7

How many MST instances does Cisco support up to?

Answer 7

16 MST by default

Question 8

Where is all the topology information contained for a MST instance within?

Answer 8

(IST) Internal Spanning Tree (Internally to MST Region)

Question 9

What is VTP pruning?

Answer 9

helps send broadcasts only to those trunk links that actually needs the information.

example, if switch A does not have a port configured for VLAN 7, and broadcast is sent throughout VLAN 7, that broadcast or traffic will not pass through the trunk link to switch A.

Question 10

What is an MST Region boundary?

Answer 10

any port that connects to a switch that’s in a different MST Region

Question 11

Does MSTIs interact outside their region?

Answer 11

no

Question 12

Making the MST Region the root bridge ensures what?

Answer 12

all region boundary ports flood the same IST instance BPDU to all VLANs in the PVST topology