Brocade Communications Systems ServerIron ADX 12.4.00 - Manual (Page 68)

56 ServerIron ADX Global Server Load Balancing Guide
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Secure GSLB
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The <ip-addr> specifies the address of the cache entry. This is not necessarily the address of a
remote site. The address you specify here is combined with the prefix length to result in a network
prefix (network portion of an IP address). The prefix length can be from 1-31.
NOTE
The prefix length 0 is not applicable to this feature and is ignored by the software.
You can enter more than one prefix on the same command line. Separate each prefix with a space.
You can configure up to 250 static prefixes on a ServerIron ADX.
The command in this example configures an entry for address 61.1.1.1 with a prefix of 20 bits.
(Due to the prefix length, the value actually stored in the cache is 61.1.0.0.20.) When the GSLB
ServerIron ADX receives RTT information for an address within the specified prefix, the GSLB
ServerIron ADX stores the information in the static prefix entry configured above, instead of
creating a dynamic entry.
Enabling default geographic location
The use-default-location command enables you to ensure that the geographic policy metric is used
to load balance client requests even if the client prefix cache maintained by the GSLB ServerIron
ADX is full.
By default, the GSLB ServerIron ADX ignores the default location of new client requests if its client
prefix cache if full. Whenever the GSLB ServerIron ADX cannot create a new entry in the client
prefix cache because it has already exceeded the limit, it ignores the geographic policy metric and
falls to the next metric in the GSLB policy.
If the use-default-location command is configured for either the global GSLB policy or the host-level
GSLB policy, the ServerIron ADX uses the default location of the client and the geographic policy
metric when determining how to distribute the client’s request.
To ensure that the geographic policy metric is used, enter commands such as the following:
ServerIronADX(config)# gslb policy

ServerIronADX(config-gslb-policy)# use-default-location
The default location of the client corresponds to the default location configured on the GSLB
controller. If no default location is configured on the GSLB controller, then n-america is assigned by
default. For more information, see
“Specifying GSLB controller locations” on page 21
Secure GSLB
Secure GSLB uses industry standard algorithms and mechanisms to authenticate and encrypt
Global Server Load Balancing (GSLB) protocol communication between the GSLB controller and
site ServerIron ADXs.
GSLB controllers and site ServerIron ADXs communicate and exchange information using the GSLB
protocol. This protocol comprises a set of messages for exchanging information, and each message
type has a unique format.
Secure GSLB communication provides the following benefits: