GSS2.0 with CNR supports GSLB (Global server load balancing) of MX
records.
Here are the details
Each query is processed as follows, depending upon its type:
*A Queries- The GSS processes these queries and responds if it finds a
reply for the query. If it fails to find a reply, it queries the CNR
subsystem for a reply. The CNR reply is then forwarded to the D-Proxy.
*All other Queries- These queries are forwarded to the CNR subsystem.
The response from the CNR subsystem is forwarded back to the D-Proxy. If
the response contains A records in the Additional Section, the GSS may
perform its own query processing and modify the Additional Section of
the Response to provide a load-balanced A records in the Additional
Section.
More information available at:
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http://www.cisco.com/en/US/products/hw/contnetw/ps4162/products_configuration_guide_chapter09186a00807e0a33.html
Section: Using the GSS as a DNS Appliance
