Nortel Web OS 10.0, Application Manual

Page: 309 / 482

Web OS 10.0 Application Guide
Chapter 12: Global Server Load Balancing
n
309
212777-A, February 2002
Figure 12-5 illustrates GSLB proximity tables. The client sends a request to the DNS server,
which is forwarded to the master switch. The master switch looks through its proximity table
and returns the request to the DNS server with the virtual server IP address of the preferred
site. The DNS server sends a new request through the Internet and connects the client to the
preferred site.
Figure 12-5 GSLB Proximity Tables: How They Work
The following example illustrated in Figure 12-6 on page 310 shows how to add entries into a
GSLB proximity table. Two client networks, A and B, are configured in the proximity table on
the master switch at Site 4. Client A with a subnet address of 205.178.13.0 is configured with
static entries for preferred Sites 1 and 3. Client B, with a subnet address of 204.165.0.0, is con-
figured with static entries for preferred Sites 2 and 4.
1. CLIENT SENDS REQUEST
TO LOCAL DNS SERVER
2. DNS REQUEST
SENT TO MASTER
SWIT CH
DATABASE FIELDS
<IP ADDRESS> <NETMASK> <VIP>
3.MASTER
SWIT CH LOOKS AT
DATABASE AND RESPONDS
4.CLIENT REQUEST FORWARDED
TO NEAREST LOCATION