Coyote Point Systems Equalizer GX Series, Administration Manual

Page: 120 / 866

Load Balancing & Networking
Source Selection
As a load balancing device Equalizer may change the source address in a packet, the destination
address in a packet, or both, before sending a packet on to the next-hop gateway. In doing so, it
will perform source address selection to determine the appropriate source address to use when a
packet is sent out on the network.
Equalizer is frequently required to choose from a number of possible source addresses when
sending packets. An example is when it sends a probe to a server behind it. Some servers will be
on a network that is local to Equalizer, and so it will chose its IP address on the appropriate VLAN
to use as the source address in a probe packet. If the server is not located on a network that is
local to Equalizer, then Equalizer will consult the source address selection table to choose a source
address, and route the packet according to the information in the source routing table.
Refer to
"Load Balancing & Networking"
on page 89for a detailed discussion of VLANs and
configuration with Equalizer.
The figure below shows the general flow of a packet through Equalizer, demonstrating the various
check points and destination selection techniques that are used. In
"Source Routing Scenarios"
on
page 121 practical scenarios are presented in “Road Map” style to demonstrate the routing
selection used.
120 Copyright © 2014 Coyote Point Systems, A Subsidiary of Fortinet, Inc.