Nortel Networks WEB OS 212777 User Manual
Page 315
Web OS 10.0 Application Guide
Chapter 13: Firewall Load Balancing
n
315
212777-A, February 2002
Alteon Web switches support the following methods of FWLB:
n
Basic FWLB for simple networks
This method uses a combination of static routes and redirection filters and is usually
employed in smaller networks.
A Web switch filter on the dirty-side splits incoming traffic into streams headed for differ-
ent firewalls. To ensure persistence of session traffic through the same firewall, distribu-
tion is based on a mathematical hash of the IP source and destination addresses.
For more information about basic FWLB, see
n
Four-Subnet FWLB for larger networks
Although similar to basic FWLB, the four-subnet method is more often deployed in larger
networks that require high-availability solutions. This method adds Virtual Router Redun-
dancy Protocol (VRRP) to the configuration.
Just as with the basic method, four-subnet FWLB uses the
hash
metric to distribute fire-
wall traffic and maintain persistence.
“Four-Subnet FWLB” on page 326
Each method is described in more detail in the following sections.