CCNAX Module 5

Question 1

Issues in Reduntant Topologies (three) high level, no detailed explanation:

Answer 1

1. Broadcast Storms
2. Multiple Frame Transmission
3. MAC Database Instability

Question 2

What layer does STP work on?

Answer 2

Layer 2

Question 3

List three STP behaviours:

Answer 3

1. STP uses BPDUs for communication between switches.
2. STP forces certain ports into standby (block), ensures only one path to each network segment (collision domain).
3. If connectivity issue, standby path automatically re-activated (if exists).

Question 4

How many root bridges can exist in one network?

Answer 4

ONE

Question 5

Does the root bridge have the highest or lowest Bridge ID (BID) value?

Answer 5

LOWEST!

Question 6

Define BPDU acronym:

Answer 6

Bridge Protocol Data Unit

Question 7

STP - describe root port:

Answer 7

• exists on non-root bridges
• switch port with best path to root bridge
• forwards traffic towards root bridge
• source MAC address of frames received on root port is capable of populating MAC table
• only one root port allowed per bridge

Question 8

STP - describe designated port:

Answer 8

• exists on root and non-root bridges
• root bridges > all switch ports are DPs
• non-root bridges > DP receive/forward frames towards root bridge
• only one DP allowed per segment
• DP can populate MAC table

Question 9

STP - describe Nondesignated Port:

Answer 9

• port switch that is blocking
• not populating MAC

Question 10

STP - describe Disabled Port:

Answer 10

• port that is shut down

Question 11

STP - what is the cost associated with each port related to?

Answer 11

SPEED

Higher interface bandwidth = lower cost

(can be manually changed)