Q-Logic 59021-05 Bandwidth, Latency, Source Port Rate, Destination Port Rate, Maximum Bandwdith

￿	3 – Planning
	Performance

3.3.2

Bandwidth

Bandwidth is a measure of the volume of data that can be transmitted at a given transmission rate. A port can transmit or receive at 1 Gbps or 2 Gbps depending on the device to which it is connected. The switch supports all transmission rate combinations as shown in Table 3-1.

Table 3-1. Port-to-Port Transmission Combinations

Source Port Rate	Destination Port Rate	Maximum Bandwdith
1 Gbps	1 Gbps	100 MB
1 Gbps	2 Gbps	100 MB
1 Gbps x 2 ports	2 Gbps	200 MB
2 Gbps	1 Gbps x 2 ports	100 MB each port1
2 Gbps	2 Gbps	200 MB

1Bandwidth will be less for larger sequence sizes.

In multiple chassis fabrics, each link between chassis contributes 100 or 200 megabytes of bandwidth between those chassis. When additional bandwidth is needed between devices, increase the number of links between the connecting switches. The switch guarantees in-order-delivery with any number of links between chassis.

3.3.3

Latency

Latency is a measure of how fast a frame travels from one port to another. The factors that affect latency include transmission rate and the source/destination port relationship as shown in Table 3-2.

Table 3-2. Port-to-Port Latency

Source/Destination Rates	Same Switch
1 Gbps - 1 Gbps	< 1 µsec
2 Gbps - 2 Gbps	< 0.5 µsec

59021-05 A 3-7