Data Center Fabric Manager Enterprise User Manual v10.3.X (53-1001357-01, November 2009)

DCFM Enterprise User Manual 373
53-1001357-01
Additional guidelines for tunnel advanced settings
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Additional guidelines for tunnel advanced settings
The following features are implemented as advanced settings on the Add FCIP Tunnel dialog box:
• Data compression.
• Open Systems Tape Pipelining (FCIP Fast Write and Tape Acceleration).
• IPSec and IKE settings for cryptographic security over IP networks.
• FICON emulation/acceleration features that improve performance in FICON environments.
• tperf test mode. See the Fabric OS FCIP Administrator’s Guide for information about tperf.
Data compression
Data compression can improve performance on long distance connections. Compression is
enabled by selecting Advanced Settings on the Add FCIP Tunnel dialog box. Compression options
are available on the Transmission tab. Compression is done by the hardware. A value of 1 enables
compression. For the 4 Gbps Router, Extension switch and blade, the compression ratio is typically
2:1. For the 8 Gbps 16-FC ports, 6-Gbps ports extension switch and the 8 Gbps 12-FC port, 10 GbE
ports, 2-10 GbE ports Extension blade, the compression ratio is typically 4:1. The 8 Gbps 16-FC
ports, 6-Gbps ports extension switch provides two additional levels of software compression.
Settings 2 and 3 provide incrementally higher compression ratios that can be used to improve
performance on slower links. A value of 0 disables compression.
Open systems tape pipelining (OSTP)
Latency introduced by a long distance IP connection can negatively impact tape I/O performance.
OSTP may be used to improve performance on SCSI write I/Os to sequential devices (such as tape
drives). When OSTP is used, the extension blades or switches emulate write commands and
responses locally to reduce delays caused by latency. Both sides of an FCIP tunnel must have
matching configurations for these features to work. OSTP may be configured by selecting Advanced
Settings on the Add FCIP Tunnel dialog. OSTP options are available on the Transmission tab.
IPSec and IKE policies
IPSec and IKE policy creation is an independent procedure. These policies must be in place before
you assign the policies when creating the FCIP tunnel, and you must have them available when you
run the FCIP Tunnel Configuration wizard. These policies are assigned by selecting Advanced
Settings on the Configure Tunnel dialog. The following limitations apply to using IPSec:
• IPv6, NAT, and AH are not supported.
• You cannot create a nonsecure tunnel on the same port as a secure tunnel.
• IPSec-specific statistics are not supported.
• Jumbo frames are not supported for IPSec.
• There is no RAS message support for IPSec.
• Only a single route is supported on an interface with a secure tunnel.
• Maximum unidirectional throughput is approximately 104 MBps.
• Maximum bidirectional throughput is approximately 104 MBps.