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Table 12-5
from the client reaches Site 2, but Site 2 has no available services.
Table 12-5 HTTP Versus Non-HTTP Redirects
Site 2 Web switch
HTTP application
1a. Client DNS request reaches Site 2.
(built-in redirection)
Resources are unavailable at Site 2.
Site 2 sends a response to Client with Site 1's
virtual server IP address.
Non-HTTP application
2a. Client DNS request reaches Site 2.
(no redirection)
Resources are unavailable at Site 2.
Site 2 sends a request to Site 1 with Site 2's
proxy IP address as the source IP address and
the virtual server IP address of Site 1 as the des-
tination IP address.
How IP Proxy Works
Figure 12-4
cations being load balanced are HTTP and POP3. Any request that cannot be serviced locally
is sent to the peer site. HTTP requests are sent to the peer site using HTTP Redirect. Any other
application request will be sent to the peer site using the IP proxy feature.
Figure 12-4 POP3 Request Fulfilled via IP Proxy
212777-A, February 2002
explains the packet -flow process in detail. In this example, the initial DNS request
shows examples of two GSLB sites deployed in California and Denver. The appli-
Web OS 10.0 Application Guide
Site 1 Web switch
1b. Client resends request to Site 1.
Resources are available at Site 1.
Site 1 completes TCP three-way handshake with
client.
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.
Site 2 completes the three-way handshake with
Client.
Chapter 12: Global Server Load Balancing
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305
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