Dell POWEREDGE M1000E - Manual (Page 402)

402 Fabric OS Administrator’s Guide
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Configuring encryption and compression
14
Changing port speed on encryption/compression enabled ports
The port speed values can be displayed through several commands, including portStatsShow,
portEncCompShow, and portCfgSpeed. However, the port speed can only be changed using the
portCfgSpeed command.
If the port speed is configured as AUTO NEG, the speed of the port is taken as 16G for calculation
purposes. We recommend that you configure to the ports to a specific speed before enabling
encryption/compression. See
“Configuring encryption and compression” on page 399 for more
details.
You can change the port speed on any port which has encryption or compression enabled with the
portCfgSpeed command. When you attempt to change speed on a port which has encryption or
compression enabled, a validation alert appears. If the capacity is available, the port will be
allowed to be configured with the new speed. If there is not enough capacity available, an error
message will appear, and you will not be able to change the port speed. See the Fabric OS
Command Reference for more details on this command.
Example Port speed change failure
switch> portenccompshow
User
Encryption Compression Config
Port configured Active Configured Active Speed
---- ---------- ------ ---------- ------ -----
0 No No Yes No 4G
1 No No Yes No 4G
2 No No Yes No 8G
3 No No Yes No 16G
4 No No Yes No 16G
switch> portcfgspeed 1 0
Configuration for port (1) failed as it exceeds current supported capacity.
Compression ratios and encryption/compression enabled ports
The compression ratio value is recalculated every 5 seconds, and is the ratio between the
accumulated original length and the compressed length of the data over the previous 5 seconds.
When a port is configured for compression, entering portStatsShow displays the port’s
compression ratio. See the Fabric OS Command Reference for more details on this command.
Limitations and restrictions
• The ASIC Compression Block can compress data only if there is at least 3 bytes of data.
• The value shown by portStatsShow is a five-second average. Your results will depend on the
pattern of the payload data.
• The average frame size reported by portCfgShow is the configured framesize, that is, what was
input using portCfgLongdistance on the CLI.
• The portBufferShow command shows the average framesize for both received (rx) and
transmitted (tx) frames. The rx values are after compression and the tx values are before
compression.