Jeremy's IT Lab CCNA QoS (Part 2) Day 47

[...] = DSCP 0

DF

[...] = DSCP 46

EF

[...] buffers traffic in a queue if the traffic rate goes over the configured rate.

Shaping

[...] delivery means there is no guarantee that data is delivered or that it meets any QoS standard.

Best effort

[...] drops traffic in a queue if the traffic rate goes over the configured rate.

Policing

AF11 = DSCP [...]

10

AF12 = DSCP [...]

12

AF13 = DSCP [...]

14

AF21 = DSCP [...]

18

AF22 = DSCP [...]

20

AF23 = DSCP [...]

22

AF31 = DSCP [...]

26

AF32 = DSCP [...]

28

AF33 = DSCP [...]

30

AF41 = DSCP [...]

41

AF42 = DSCP [...]

36

AF43 = DSCP [...]

38

CoS/PCP 0 = [...]

best effort

CoS/PCP 3 = [...]

critical applications

CoS/PCP 4 = [...]

video traffic

CoS/PCP 5 = [...]

voice traffic

CoS/PCP [...] = best effort

0

CoS/PCP [...] = critical applications

3

CoS/PCP [...] = video traffic

4

CoS/PCP [...] = voice traffic

5

CS0 = DSCP [...]

0

CS1 = DSCP [...]

8

CS2 = DSCP [...]

16

CS3 = DSCP [...]

24

CS4 = DSCP [...]

32

CS5 = DSCP [...]

40

CS6 = DSCP [...]

48

CS7 = DSCP [...]

56

DF = DSCP [...]

0

DSCP: What does AF stand for?

assured forwarding

DSCP: What does CS stand for?

class selector

DSCP: What does DF stand for?

default forwarding

DSCP: What does EF stand for?

expedited forwarding

EF = DSCP [...]

46

If an IP phone is connected to a switchport, the QoS trust boundary should be at the [...].

IP phone

IP phones mark their call signaling traffic as PCP/CoS [...].

3

LLQ designates one or more queues as [...] queues.

strict priority

RFC 4594 recommends the [...] marking for best effort traffic.

DF

RFC 4594 recommends the [...] marking for high priority data traffic.

AF2x (AF21, AF22, AF23)

RFC 4594 recommends the [...] marking for interactive video traffic.

AF4x (AF41, AF42, AF43)

RFC 4594 recommends the [...] marking for streaming video traffic.

AF3x (AF31, AF32, AF33)

RFC 4594 recommends the [...] marking for voice traffic.

EF

The IPP precedence field was [...] in length.

3 bits

What does CBWFQ stand for?

Class-Based Weighted Fair Queuing

What does IPP stand for?

IP Precedence

What does LLQ stand for?

Low Latency Queuing

What does NBAR stand for?

Network Based Application Recognition

What Layer 2 header field can be used for QoS markings?

PCP / CoS

What Layer 3 header field can be used for QoS markings?

DSCP

(formerly IPP)

What QoS scheduling algorithm uses a weighted round-robin scheduler while guaranteeing a minimum bandwidth to each queue?

CBWFQ