Hashed cookie persistence – Extreme Networks Px Series User Manual

Page 66

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6-8

Px Series Application Switch Installation and Configuration Guide

# Additional information may be useful during debugging

print start_html('Cookie Tester');

if (!$ExistingHostCookie) {

print "No cookie named $SLBCookie existed<br>\n";

print "It was set to the local host address of $HostIPAddr<br>\n";

}

elsif ($ExistingHostCookie ne $HostIPAddr) {

print "The cookie named $SLBCookie was set for host

$ExistingHostCookie<br>\n";

print "It was reset to the local host address of $HostIPAddr<br>\n";

}

else {

print "The cookie named $SLBCookie was correctly set to

$ExistingHostCookie<br>\n";

print "No action was taken<br>\n";

}

print end_html;

Hashed Cookie Persistence

Using hashed cookie persistence, unique information about the client is placed in the
cookie. When the application switch examines the cookie, it performs a mathematical
hash of the unique contents of the cookie. The mathematical hash operation always
renders the same numeric value for the cookie. In other words, a given cookie is always
forwarded to the same server until the size of the server pool changes.

Figure 6-3 illustrates hashed cookie persistence.

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