Q

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

< 0.4 µsec

 

 

59021-05 B

3-7

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Q-Logic 59021-05 B manual Bandwidth, Port-to-Port Transmission Combinations, Port-to-Port Latency