Bandwidth; Latency - Qlogic SANbox 5602 Installation Manual

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You can configure recipient and donor ports using the SANsurfer Switch Manager
application or the Set Config command. Refer to
page B-61
3.3.2

Bandwidth

Bandwidth is a measure of the volume of data that can be transmitted at a given
transmission rate. A 1-Gbps/2-Gbps port can transmit or receive at nominal rates
of 1-, 2-, or 4-Gbps depending on the device to which it is connected. This
corresponds to actual bandwidth values of 106 MB, 212 MB, and 425 MB
respectively. 10-Gbps ports transmit at a nominal rate of 10-Gbps which
corresponds to an actual bandwidth value of 1275 MB. Multiple source ports can
transmit to the same destination port if the destination bandwidth is greater than or
equal to the combined source bandwidth. For example, two 1-Gbps source ports
can transmit to one 2-Gbps destination port. Similarly, one source port can feed
multiple destination ports if the combined destination bandwidth is greater than or
equal to the source bandwidth.
In multiple chassis fabrics, each link between chassis contributes 106, 212, 425,
or 1275 megabytes of bandwidth between those chassis depending on the speed
of the link. 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
Based on minimum size frame of 36 bytes. Latency increases for larger frame sizes.
1
59096-01 A
for more information.
Table
Table 3-2. Port-to-Port Latency
Gbps 1
< 0.6 µsec
1
< 0.5 µsec
2
< 0.4 µsec
4
< 0.4µsec
10
"Set Config Command" on
3-2.
Destination Rate
2 4
< 0.8 µsec 1 < 0.8 µsec
< 0.4 µsec
< 0.4 µsec
< 0.3 µsec < 0.3 µsec
< 0.3 µsec < 0.2 µsec
3 – Planning
Performance
10
1 < 0.8 µsec 1
< 0.4 µsec
1 1
< 0.3 µsec
1
< 0.2 µsec
3-5