Owner's manual

HP ProCurve Switch 4000M / 8000M / 2424M / 1600M Reviewer’s Guide

6.2.3 Latency Test - broadcast traffic

In this SmartApplications test a 64 byte broadcast packet is sent into port 1 of the switch. The FIFO

time it takes for the packet to emerge from the different ports is then recorded. The important

measurement here is the variability between ports.

6.2.3.1 100Mbps

64 byte broadcast packet

Port Latency 13 12.0µs

2 13.5µs 14 12.5µs

3 12.0µs 15 13.1µs

4 12.5µs 16 13.5µs

5 13.0µs 17 12.0µs

6 13.5µs 18 12.7µs

7 13.0µs 19 11.7µs

8 13.3µs 20 12.2µs

9 11.7µs 21 12.9µs

10 12.2µs 22 13.3µs

11 12.7µs 23 11.7µs

12 13.3µs 24 12.3µs

Mean:

12.63 (Calculated FIFO) 7.51 (Calculated LIFO)

Average Deviation: 0.54 (Calculated)

6.2.3.2 10Mbps

64 byte broadcast packet

Port Latency 13 86.7µs

2 89.4µs 14 87.3µs

3 87.7µs 15 87.6µs

4 88.4µs 16 88.2µs

5 89.0µs 17 86.9µs

6 89.5µs 18 87.6µs

7 89.1µs 19 86.3µs

8 89.1µs 20 87.0µs

9 87.9µs 21 87.4µs

10 88.0µs 22 88.2µs

11 88.6µs 23 86.6µs

12 89.5µs 24 87.2µs

Mean:

97.97 (Calculated FIFO) 36.77 (Calculated LIFO)

Average Deviation: 0.82 (Calculated)

See the Latency discussion in section 3 of this guide for details on FIFO versus LIFO figures.