Web OS 10.0 Application Guide
426 Chapter 16: Persistence 212777-A, February 2002
Cookie Properties
Cookies are configured on the Web switch by defining the following properties:
nCookie names of up to 20 bytes
nThe offset of the cookie value within the cookie string
For security, the real cookie value can be embedded somewhere within a longer string.
The offset directs the Web switch to the starting point of the real cookie value within the
longer cookie string.
nLength of the cookie value
This defines the number of bytes to extract for the cookie value within a longer cookie
string.
nWhether to find the cookie value in the HTTP header (the default) or the URL
nCookie values of up to 64 bytes for hashing
Hashing on cookie values is used only with the passive cookie mode (“Passive Cookie
Mode” on page 428), using a temporary cookie. The switch mathematically calculates the
cookie value using a hash algorithm to determine which real server should receive the
request.
nAn asterisk (*) in cookie names for wildcards
For example, Cookie name = ASPsession*
Client Browsers that Do Not Accept Cookies
Under normal conditions, most browsers are configured to accept cookies. However, if a client
browser is not configured to accept cookies, you must use hash as the load-balancing metric
to maintain session persistence.
With cookie-based persistence enabled, session persistence for browsers that do not accept
cookies will be based on the source IP address. However, individual client requests coming
from a proxy firewall will appear to be coming from the same source IP address. Therefore, the
requests will be directed to a single server, resulting in traffic being concentrated on a single
real server instead of load balanced across the available real servers.