4A0-107 Nokia Quality of Service Questions and Answers

IOM3

FP3 based IMM

IOM1

IOM2

Access ingress, access egress, network egress

Access ingress, network ingress, network egress

Port ingress, port egress, shared bi-directional

Port ingress, port egress, network egress

Port ingress, network ingress, network egress

WRED monitors the shared buffer space utilization over a period of time.

WRED disables the TCP slow-start congestion control mechanism.

WRED uses two configurable slopes for each buffer pool: a high slope and a low slope.

WRED uses the shared buffer utilization, instead of the individual queue depth, to get a better picture of the average resource utilization of the shared buffer space.

WRED polices the shared buffer pool and marks all packets above a certain rate as "discard eligible."

Scheduler policies cannot be children of an egress port-scheduler.

HQoS provides a static method of allocating scheduling resources to each queue and/or child.

Scheduler policies can be applied to the MDA to schedule network ingress traffic.

Every time a scheduler-policy is assigned to a SAP, a new hardware scheduler is created to service the SAP.

A scheduler applied to multiple SAPs within the same service will result in a single hardware scheduler operating across all SAPs within the service.

Burst-limit sets a limit on the maximum burst of packets transmitted during each scheduler visitation time.

Proper configuration of the burst-limit can prevent packet drops on the downstream nodes resulting from traffic bursts.

The lower the configured burst limit value, the lower the burst allowed to enter the queue.

If the burst-limit is not configured, a default burst-limit value will be used by the queue.

The process of delaying packets within a traffic stream to have them conform to a defined traffic profile.

The overall treatment of a defined subset of a customer's traffic within a DiffServ domain.

The process of discarding packets within a traffic stream in accordance with the state of a meter to enforce a defined traffic profile.

The action of setting the DiffServ codepoint of a packet prior to its entry into a downstream DiffServ domain.

A specified algorithm or operation that is implemented in a node in order to realize one or more per-hop behaviors.

DSCP value

802.1p value

IP DF bit

TCP/UDP port numbers

HTML version number

Profile-mode and priority-mode queues can only be configured on SAP ingress.

For network egress, egress re-classification can change the profile marked at ingress.

For SAP egress, the profile marked at ingress may change based on the scheduling loop.

For network ingress, the network policy can classify the packet as either in-profile, or out-of-profile.

It will be stored in the reserved buffer space and remain out-of-profile.

It will be stored in the reserved buffer space and become in-profile.

It will contend for shared buffer space with packets from other queues.

It will be discarded because the high-priority-only threshold has been reached.

010011

100010

010001

001100

010010

A device that provides no differentiation between customer traffic flows.

A device that classifies and marks customer traffic.

A device that uses MPLS EXP bits to differentiate between traffic flows.

A device that creates macroflows towards the core from multiple customer sites.

A device that passes macroflows while optionally changing QoS markings.

It will be classified into forwarding class BE and stored in queue 1.

It will be classified into forwarding class BE and stored in queue 8.

It will be classified into forwarding class NC and stored in queue 1.

It will be classified into forwarding class NC and stored in queue 8.

Every forwarding class can be associated with its own queue without sharing with other forwarding classes.

A 3-tier scheduling policy can be applied at SAP-ingress/SAP-egress.

For each unicast queue in a SAP-ingress or network-queue policy, there is a separate hardware queue for each destination FFPC.

Policing can be deployed instead of queuing at ingress.

The slope-policy

The SAP-ingress policy

The SAP-egress policy

The network-queue policy

The scheduler-policy

SAP-ingress policy

SAP-egress policy

IP-criteria policy

Network-queue policy

Slope policy

Network policy

Profile/priority state of a packet

Forwarding class

Queue depth

HPO setting

dot1p

dst-mac

lsp-exp

dscp

There are a maximum of 8 levels of priority serviced using a round-robin algorithm.

The default scheduler will spend an equal amount of time in each queue, as long as there is traffic present

The H1 internal forwarding class will receive its CIR before AF traffic.

Orphaned queues will be scheduled out of the BE queue.

A queue servicing EF and AF traffic will require explicit configuration to set the queue to expedited.

The DSCP value will be set to af21.

The DSCP value will be set to af23.

The DSCP value will remain as ef.

The EXP value, in the MPLS headers, will be set to 4.

The EXP value, in the MPLS headers, will be set to 3.

8

16

6

4

3

3

4

6

8

Queue 6 within-CIR packets, then queue 5 within-CIR packets, then queue 5 and queue 6 above-CIR packets in round-robin.

Queue 6 within-CIR packets, then queue 5 within-CIR packets, then queue 5 and queue 6 above-CIR packets in biased round-robin.

Queue 6 within-CIR packets, then queue 5 within-CIR packets, then queue 6 above-CIR packets, and finally queue 5 above-CIR packets.

Queue 6 and queue 5 within-CIR packets in biased round-robin, then queue 5 and queue 6 above-CIR packets in round-robin.

All in-profile packets in round-robin, then all out-of-profile packets in biased round-robin.

In-profile EF packets, then in-profile H2 packets, then in-profile AF packets, then out-of-profile EF packets, then out-of-profile H2 and AF packets, and then out-of-profile BE packets.

In-profile EF, H2 and AF packets, then out-of-profile H2, AF and BE packets in biased round-robin.

In-profile EF packets, then in-profile H2 and AF packets, then out-of-profile H2, AF and BE packets in biased round-robin.

In-profile EF and H2 packets, then in-profile AF packets, then out-of-profile H2, AF and BE packets in biased round-robin.

SAP-ingress policy

SAP-egress policy

IP-criteria policy

Network-queue policy

Slope policy

Network policy

2

3

5

6

None of the above.

0

min

max D. 50000

16

8

32

48

56

802.1p bits

Precedence

DSCP

EXP

All forwarded packets will be in-profile

Packets forwarded above CIR will be marked out-of-profile and the rest will be in-profile

Excess packets that arrive within a burst larger than CBS will be forwarded as out-of-profile

All forwarded packets will be out-of-profile

A queue will be serviced as expedited if all of the forwarding classes mapped to it are expedited, regardless of its configured type.

A queue will be serviced as best-effort if all of the forwarding classes mapped to it are best-effort, regardless of its configured type.

A queue will be serviced as expedited if at least one of the forwarding classes mapped to it is expedited, regardless of its configured type.

A queue will be serviced as expedited if its type is configured as expedited, regardless of the forwarding classes mapped to it.

L2

H1

AF

BE