HP Traffic Director sa7220 - Manual (Page 37)

C H A P T E R 2 Server Configuration Options
25
Multi-hop Source Address Preservation
It is possible in sophisticated network topologies to require requests
to pass through two SA8220s. In such configurations, the SA8220
topologically closest to the clients must be configured with the Multi-
hop Source Address Preservation (MSAP) feature enabled.
MSAP allows requests to pass through two cascaded SA8220s in
different geographical areas. Enabling MSAP ensures that the actual
IP addresses of requesting clients, rather than the virtual IP address of
the SA8220 that delivered the request, are recorded in the server logs.
This is similar to SAP (described in the preceding section), however
this feature allows SA8220s to be geographically-dispersed, as
shown in below.
MSAP on a Geographically-Dispersed Network
NOTE: In most
configurations, the
default setting (MSAP
disabled) is required. In the figure above, a client in San Diego sends a request to a
fulfillment server in Boston. MSAP is enabled on SA8220 Broker 1,
and Server 1’s default route is set to SA8220 Broker 2. The SA8220
Broker 2 doesn’t need SAP enabled for this service, since SAP is
automatically used on MSAP requests from SA8220 Broker 1. Under
this configuration, the San Diego client's IP address will be preserved
in the Boston fulfillment servers' logs. MSAP is enabled at the CLI
with the following command:
config policygroup service
server
port < > msap [enable]
RICH Expressions (not available on the SA7200)
Layer 7 RICH_HTTP service configurations use rich expressions to
assign particular classes of URLs to particular servers for fulfillment.
RICH expressions are used, for example, to distinguish content
requested by clients performing online transactions, from content
typically requested by casual browsers. In this way, users performing
online transactions are given higher priority access to server
resources (and better response times) than other users.
B os ton S an Diego
S A8220 #1
with MS AP
E nabled
S A8220 #2
with MS AP
Dis abled
Client S erver 1
B os ton S an Diego
S A8220 #1
with MS AP
E nabled
S A8220 #1
with MS AP
E nabled
S A8220 #2
with MS AP
Dis abled
S A8220 #2
with MS AP
Dis abled
Client Client S erver 1 S erver 1