Figure 6-11 Layer 4 Dns Load Balancing - Nortel Web OS Switch Software Application Manual

Domain Name Server (DNS) Load Balancing
In previous releases of Web OS, DNS load balancing was based on virtual server IP address
and virtual port (VPORT) only. In Web OS 10.0 however, DNS load balancing allows you to
choose the service based on the two forms of DNS queries: UDP and TCP. This enables the
switch to send TCP DNS queries to one group of real servers and UDP DNS queries to another
group of real servers. The requests are then load balanced among the real servers in that group.
Figure 6-11
Client

Figure 6-11 Layer 4 DNS Load Balancing

N
OTE
IP address.
212777-A, February 2002
shows four real servers load balancing UDP and TCP queries between two groups.
Internet
–
You can configure both UDP and TCP DNS queries for the same virtual server
Group 1
UDP
health udpdns
vip 20.20.20.20
Web Switch
Group 2
TCP
health dns
Chapter 6: Server Load Balancing
Web OS 10.0 Application Guide
Real servers
10.10.10.20
20
10.10.10.21
21
Real servers
22
26
10.10.10.22
10.10.10.26
n
151