Alteon Application Switch Operating System Application Guide
Global Server Load Balancing
Document ID: RDWR-ALOS-V2900_AG1302
753
Configuring GSLB with Proxy IP for Non-HTTP Redirects
Typically, client requests for HTTP applications are redirected to the location with the best response
and least load for the requested content. The HTTP protocol has a built-in redirection function that
allows requests to be redirected to an alternate site. However, if a client requests a non-HTTP
application such as FTP, POP3, or SMTP, then the lack of a redirection functionality in these
applications requires that a proxy IP address be configured on the client port. The client port
initiates a redirect only if resources are unavailable at the first site.
Note:
This feature should be used as the method of last resort for GSLB implementations in
topologies where the remote servers are usually virtual server IP addresses in other Alteons.
Figure 126 - HTTP and Non-HTTP Redirects, page 754
illustrates the packet-flow of HTTP and non-
HTTP redirects in a GSLB environment. The following table explains the HTTP or non-HTTP request
from the client when it reaches Site 2, but Site 2 has no available services.
Table 64: HTTP versus Non-HTTP Redirects
Application Type
Site 2 Alteon
Site 1 Alteon
HTTP application (built-in
redirection)
1a—The client HTTP request
reaches Site 2. Resources are
unavailable at Site 2. Site 2 sends
an HTTP redirect to a client with
Site 1’s virtual server IP address.
2a—The client resends the
request to Site 1. Resources are
available at Site 1.
Non-HTTP application (no
redirection)
1b—The client non-HTTP request
reaches Site 2. Resources are
unavailable at Site 2. Site 2 sends
a request to Site 1 with Site 2’s
proxy address as the source IP
address and the virtual server IP
address of Site 1 as the destination
IP address.
2b—Site 1 processes the client
proxy IP request. Resources are
available at Site 1. Site 1 returns
request to proxy IP port on Site 2.