HP e-Commerce / XML director server appliance sa8250 - Users Guide

C H A P T E R 2 HP e-Commerce/XML Director Server Appliance SA8250 User Guide
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Out-of-Path Return (OPR)
NOTE: OPR is not
applicable to Layer 7
services.
Ordinarily, the SA8250 processes all traffic in both directions
between clients and the server farm. Viewing the server return traffic
helps the SA8250 accurately determine server response times and
handle HTTP errors. Often, the volume of data sent from the server
to the client is much larger than the traffic from client to server. In
such situations, you can use OPR mode to increase performance.
You enable OPR by typing this command:
config policygroup <name> service <name> server
<name> port <port> mode opr
Each server for which OPR is enabled must have its loopback
interface configured to identify itself as the VIP of the brokered
service. This allows the server to respond directly to the client. The
server’s loopback interface, or an equivalent interface that will not
respond to Address Resolution Protocol (ARP) requests, must be
configured before setting up the SA8250 for OPR. For more
information, see Appendix D.
FTP
Limitations
This table lists those limitations of FTP on the SA8250.
HOT with SAP does not change the server’s IP address during Passive
FTP because the server is making the connection directly to the client,
using its real IP address. If the server’s IP address is not a "real" IP
address, this mode will not work.
Mode Active FTP Passive FTP
HOT
No Yes
HOT with SAP
Yes Yes (see below)
OPR
No No
FTP Limitations