Alteon Application Switch Operating System Application Guide
Global Server Load Balancing
Document ID: RDWR-ALOS-V2900_AG1302
707
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GSLB is easy to deploy, manage, and scale. Alteon configuration is straightforward. There are no
complex system topologies involving routers, protocols, and so on.
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Flexible design options are provided.
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All IP protocols are supported.
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Supports IPv4, IPv6, and mixed IP version environments.
How GSLB Works
A GSLB device performs or initiates a global server selection to direct client traffic to the best server
for a given domain during the initial client connection.
GSLB is based on the Domain Name System (DNS) and proximity by source IP address. In the
example in
Figure 119 - DNS Resolution with GSLB, page 707
, a client is using a Web browser to
view the Web site for the Example Corporation at “www.example.com”. The Example Corporation
has two Web sites: one in San Jose and one in Denver, each with identical content and available
services. Both Web sites have an Alteon configured for GSLB, with domain name set to
“www.gslb.example.com.” These devices are also configured as the Authoritative Name Servers for
“www.example.com.” On the company master DNS server, the configuration is to delegate
“www.example.com” to “www.gslb.example.com”.
Figure 119: DNS Resolution with GSLB
The DNS resolution for this GSLB configuration is as follows:
1. The client Web browser requests the "www.example.com" IP address from the local DNS.
2. The client's DNS asks its upstream DNS, which in turn asks the next, and so on, until the
address is resolved.
Eventually, the request reaches an upstream DNS server that has the IP address information
available or the request reaches one of the Example, Inc. DNS servers.
