Nokia 4A0-107 - Nokia Quality of Service

8

16

6

4

3

SAP-ingress only

SAP-egress only

SAP-ingress and SAP-egress

Network ingress

Network egress

The three most significant (first) bits define 8 forwarding classes.

The three least significant (last) bits of the DSCP specify the drop probability.

The full 8 bits of the TOS field are used for DSCP.

To convert DSCP to IP precedence, the three most significant (first) bits are matched.

DSCP provides for eight drop probabilities.

When using profile-mode queues, traffic that is marked as in-profile on ingress and scheduled in the above-CIR loop will still be considered as in-profile at egress.

When an HQoS strategy using an egress port-scheduler has been deployed, Tier 1 receives its scheduling rates based on the amount of egress bandwidth available for each forwarding class.

The greater the difference between PIR and CIR rates in a queue, the less likely a CIR will be provided.

Packets scheduled out of high-priority queues in the default scheduler will have a lower chance of packet loss at the expense of incurring a higher probability of delay.

When using priority-mode queues, traffic that is marked as in-profile on ingress and scheduled in the above-CIR loop will be considered as in-profile at egress.

The larger the configured MBS value, the lower the amount of shaping performed.

When policing is enabled on the SAP-ingress, all traffic is considered as in-profile.

Setting the CIR to 1000 and the PIR to max will enable shapeless policing at 1 Mbps within the SAP-egress policy.

Configuring MBS to equal CBS will disable shaping.

Setting the CIR and PIR to equal values disables soft-policing.

It is important that all packets are classified in the same way at all SAP-ingress points.

Once a packet is classified to a forwarding class, it cannot change across the network.

Packet enters a node will be treated as per the local hop's configured policy.

Native IP packets entering a network port will be marked at the first network egress by default

Native IP packets entering a network port will not be marked at the first network egress by default.

Native IP packets entering a network port will be marked at the first network egress, regardless of the re-marking configuration.

EXP markings on transit control traffic are not set correctly.

The priority of all self-generated traffic needs to be lowered to allow all other traffic to take precedence.

The priority of various control packets requires special treatment throughout the network.

The BGP process is consuming too many CPU cycles and is impacting OSPF performance.

1

2

3

4

5

8

When applied at the FP (Forwarding Path) level for access egress

When applied at an access port for ingress or egress

When applied at the FP (Forwarding Pass) level for access ingress

When applied at the port level for network egress

Shapeless policing at SAP-ingress only.

Shapeless policing at SAP-ingress and egress.

Biased round robin queuing at ingress only.

Soft shaping at all network interfaces.

Soft shaping at network ingress only.