ServerIron ADX Global Server Load Balancing Guide 41
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Configuring GSLB protocol parameters 1
•The number of eligible IP addresses to be evaluated by the weighted IP metric and their
weights
•The weight assigned to the IP address
If an IP address has a relative weight of zero, or if it does not have a weight assigned to it, the IP
address is not selected as the best IP address for a client.
If two or more IP addresses have the same relative weight, or if all of the IP addresses have a
relative weight of zero, all of the IP addresses with the same relative weight are passed on to the
next step in the GSLB algorithm, where the process of selecting the best IP address continues.
Configuring weighted IP metrics
To configure weighted IP metrics, complete the following tasks.
1. Enable the weighted IP metric.
2. Assign weights to the IP addresses.
For example, to enable the weighted IP metric, add the zone gslb.com, add the host www within the
gslb.com zone, and assig n a weight of 50 to the IP address 1.1.1.80, enter commands such as the
following:
SLB-ServerIronADX(config-gslb-policy)# weighted-ip
SLB-ServerIronADX(config-gslb-policy)# gslb dns zone gslb.com
SLB-ServerIronADX(config-gslb-dns-gslb.com)# host www http
SLB-ServerIronADX(config-gslb-dns-gslb.com)# host www ip-weight 1.1.1.80 50
Syntax: [no] weighted-ip
Syntax: [no] gslb dns zone <name>
For <name>, enter up to 32 cha racters
Syntax: [no] host-info <host-name> <host-application> | <tcp/udp-portnum>
The <host-name> parameter specifies the host name. You do not need to enter the entire fully
qualified host name. Enter only the host portion of the name. For example, if the fully qualified host
name is www.gslb.com, do no enter the entire name. Enter only "www". The rest of the name is
already specified by the gslb dns zone command.
The <host-application> parameter specifies the host application for which you want to create an IP
list. Specify one of the following:
•ftp: the well-known name for port 21. (Ports 20 and 21 both are FTP ports but on the
ServerIron ADX, the name “ftp” corresponds to port 21.)
•tftp: the well-known name for port 69
•http: the well-known name for port 80
•imap4: the well-known name for port 143
•ldap: the well-known name for port 389
•nntp: the well-known name for port 119
•pop3: the well-known name for port 110
•smtp: the well-known name for port 25
•telnet: the well-known name for port 23
The <tcp/udp-portnum> parameter specifies a TCP/UDP port number instead of a well-known port.
Syntax: host-info www ip-weight <IP address> <weight>