Foundry Networks FESX User Manual

Configuring IP
December 2005 © Foundry Networks, Inc. 16 - 55
Figure 16.7 DHCP requests in a network with DHCP Assist operating on a FastIron
When the stamped DHCP discovery packet is then received at the router, it is forwarded to the DHCP server. The
DHCP server then extracts the gateway address from each request and assigns an available IP address within the
corresponding IP sub-net (Figure 16.8). The IP address is then forwarded back to the workstation that originated
the request.
NOTE: The DHCP relay function of the connecting router needs to be turned on.
Server
Server
DHCP
Server
207.95.7.6
Host 1
200.95.6.x
Host 2
192.95.5.x
Sub-net 1
Host 3 Host 4
Router
202.95.1.x
Sub-net 3
Sub-net 2
Step 1:
DHCP IP address requests
for Hosts 1,2,3 and 4 in
Sub-nets 1, 2, 3 and 4
202.95.5.x
Sub-net 4
192.95.5.1
200.95.6.1
202.95.1.1
202.95.5.1
Step 2:
FastIron stamps each DHCP request
with the gateway address of the
corresponding subnet of the
receiving port.
Gateway addresses:
Step 3:
Router forwards the DHCP request to the
server without touching the gateway
address inserted in the packet by the switch
Interface 2
Interface 8
Interface 14
FESX
Hub

Foundry Networks FESX Specifications

General

Brand	Foundry Networks
Model	FESX
Category	Switch
Language	English