Riverstone Networks WICT1-12 - Manual (Page 504)

22-6 Riverstone Networks RS Switch Router User Guide Release 8.0
Load Balancing Web Hosting Configuration
Checking Servers and Applications
The RS automatically performs the following types of verification for the attached load balancing servers/applications:
• Verifies the state of the server by sending a ping to the server at 5-second intervals. If the RS does
not receive a reply from a server after four ping requests, the server is considered to be “down.”
• Checks that an application session on the server can be established by doing a simple TCP handshake
with the application on the configured physical port of the server at 15-second intervals. If the RS
does not receive a reply from the application after four tries, the application is considered to be
“down.”
You can change the intervals at which pings or handshakes are attempted and the number of times that the RS retries
the ping or handshake before considering the server or application to be “down.” You can change these parameters for
all servers in a load balancing group or for specific servers.
The following example modifies the defaults for the pings from the RS to the “mktgroup” server group:
The following example sets the time between handshakes at port 80:
In addition, the RS can also check the status of any attached Domain Name Servers (DNS) servers and RADIUS
servers. To verify the state of a DNS server, the RS sends a lookup request for a host name. The RS then checks the
response of the DNS server for the specified IP address and host-name. The following example sets the IP address and
host name:
The RS verifies the status of a RADIUS server by sending it queries and verifying the response it receives. You define
the user name, password, and MD5 encryption key that the RS will include in its queries. You can specify invalid
values for the user name and password. A positive response to a query with valid values or a negative response to a
query with invalid values indicates that the RADIUS server is “up.” The following example sets the values for the
query to the RADIUS server:
rs(config)# load-balance set group-options mktgroup ping-tries 3 ping-int 10
rs(config)# load-balance set server-options 135.142.179.14 app-int 8 port 80
rs(config)# load-balance set group-options mktgroup dns-host-ip 135.142.179.10
dns-host-name www-fast
rs(config)# load-balance set group-options mktgroup radius-username radiusserv
radius-password a1b2c3e4f5 radius-md5 abcdegh