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egress-quantization

Syntax

Hierarchy Level

Description

Selective dynamic load balancing selects an optimal link based on:

  • Port load metric - Amount of traffic in bytes transmitted in recent past over each ECMP link.

  • Port queue metric - Amount of traffic in number of cells enqueued on each ECMP link for transmission.

Use egress-quantization to configure the desired ratio of port load metric to port queue metric based on the traffic pattern. Member link quality is quantized in the range of 0 to 7. A link quality value of 0 indicates the worst quality link whereas a value of 7 indicates a best quality link. Quantization levels can be configured by setting minimum and maximum thresholds along with rate-weightage.

Rate-weightage is the ratio of port load metric to port queue metric. Assume rate-weightage is configured as 60%. Then a link is chosen amongst competing links if the link has a higher port load metric than its port queue metric.

Minimum threshold is the minimum bandwidth threshold level of the total link bandwidth. When bandwidth level drops below this level, the device assigns this link with a best quality band value (value 7). Assume the value set is 20. When the ECMP link transmits traffic lower than 20% of link bandwidth, the device assigns a best quality band value to this link.

Maximum threshold is the maximum bandwidth threshold level of the total link bandwidth. When bandwidth level rises above this level, the device assigns this link with a worst quality band value (value 0). Assume the value is set to 80. When the ECMP link transmits traffic higher than 80% of the link bandwidth, the device assigns worst quality band value to this link.

The following table summarizes egress quantization link quality values.

Table 1: Egress quantization link quality values

Egress quantization when egress rate weightage is configured with value of 100%

Egress Link Bandwidth utilization

Quality Band

Lesser than 20

7 (Best)

21-30

6

31-40

5

41-50

4

51-60

3

61-70

2

71-80

1

Greater than 80

0 (Worst)

Default

When selective dynamic load balancing is configured, the default ratio of port load metric to port queue rate weightage is 50:50 for per-packet mode and flowlet-mode. The default values of minimum threshold value and maximum threshold value are:

Per-packet mode

  • EgressBytes Min Threshold - 80

  • EgressBytes Max Threshold - 99

Flowlet mode

  • EgressBytes Min Threshold - 20

  • EgressBytes Max Threshold - 50

Options

  • apply-groups

  • max

  • min

  • rate-weightage

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS EVO 22.X100-D20