stp_flashcards

Question 1

Front

Answer 1

Back

Question 2

What is BUM traffic?

Answer 2

Broadcast, Unknown Unicast, and Multicast<br></br>*the kinds of frames flooded by switches

Question 3

What are the three main steps of the STP algorithm?<br></br>1) <br></br>2) <br></br>3) 

Answer 3

1) Root bridge election<br></br>2) Root port selection<br></br>3) Designated port selection

Question 4

STP: What are the root bridge election criteria?

Answer 4

1) Lowest BID

Question 5

STP: What are the <b>root port</b> selection criteria?

Answer 5

1) Lowest root cost<br></br>2) Lowest neighbor BID<br></br>3) Lowest neighbor port ID<br></br>4) Lowest local port ID

Question 6

STP: What are the <b>designated port</b> selection criteria?

Answer 6

1) Port on switch with lowest root cost<br></br>2) Port on switch with lowest BID<br></br>3) Lowest local port ID

Question 7

In classic STP (802.1D), which switch/switches generate new BPDUs?

Answer 7

Only the root bridge

Question 8

STP BPDUs are only forwarded out of […] ports.

Answer 8

Designated

Question 9

What are the two fields of the STP BID?

Answer 9

Bridge Priority (16 bits)<br></br>MAC Address (48 bits)

Question 10

What are the two sections of the STP Bridge Priority?

Answer 10

Priority (4 bits) <br></br>Extended System ID (12 bits)

Question 11

In PVST+, what is the significance of the Extended System ID?

Answer 11

It is the VLAN ID of the instance

Question 12

What is the root cost of the STP root bridge?

Answer 12

0

Question 13

When an STP switch receives a BPDU from the root bridge, what cost does it add?

Answer 13

The cost of the receiving port

Question 14

A port’s STP cost is derived from the […] value.

Answer 14

bandwidth

Question 15

In STP, there must be one designated port per […].

Answer 15

segment (collision domain)