Cisco MDS 9000 series Configuration Manual page 54

Configuring FCIP
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Figure 2-15
Restore
Server
The Cisco NX-OS provides reliable data delivery to the restore application using TCP/IP over the WAN.
While tape media errors during the read operation are returned to the restore server for error handling,
the Cisco NX-OS software recovers from any other errors.
Note The FCIP tape acceleration feature is disabled by default and must be enabled on both sides of the FCIP
link. If it is only enabled on one side of the FCIP tunnel, the tape acceleration feature is turned
operationally off.
FCIP tape acceleration does not work if the FCIP port is part of a PortChannel or if there are multiple
Tip
paths between the initiator and the target port. Such a configuration might cause either SCSI discovery
failure or broken write or read operations.
Caution When tape acceleration is enabled in an FCIP interface, a FICON VSAN cannot be enabled in that
interface. Likewise, if an FCIP interface is up in a FICON VSAN, tape acceleration cannot be enabled
on that interface.
When you enable the tape acceleration feature for an FCIP tunnel, the tunnel is reinitialized and the write
Note
and read acceleration feature is also automatically enabled.
In tape acceleration for writes, after a certain amount of data has been buffered at the remote Cisco MDS
switch, the write operations from the host are flow controlled by the local Cisco MDS switch by not
proxying the Transfer Ready. On completion of a write operation when some data buffers are freed, the
local Cisco MDS switch resumes the proxying. Likewise, in tape acceleration for reads, after a certain
Cisco MDS 9000 Family NX-OS IP Services Configuration Guide
2-30
FCIP Link Tape Acceleration for Read Operations
MDS with
IPS
Read command N
Read data N
Status N
Read command N+1
Status N+1
MDS with
IPS
WAN
Read command N
Read data N
Status N
Read command N+1
Read data N+1
Status N+1
Read command N+2
Chapter 2
Tape
Drive
FC FC
Read data N
Status N
Status N+1
OL-19525-01,Cisco MDS NX-OS Release 4.2(1)
Configuring FCIP