Avaya Media Gateway G250, Administration Manual

Page: 515 / 840

Configuring DHCP server
Issue 5 June 2008 515
Typical DHCP server application
In the typical application shown in Figure 37 , the G250/G350 is configured as a local DHCP
server and router for IP phones and PCs in the branch office. The remote DHCP server
allocates IP addresses for headquarters users. In case of WAN failure, the local DHCP server
can still allocate IP addresses in the branch offices. If there is a local ICC or LSP, calls can still
be made. If there is no ICC or LSP to control calls, the DHCP server can allocate IP addresses
to all devices, but, since no calls can be made, the IP address allocation effectively applies to
PCs only.
Figure 37: G250/G350 as server and router
The branch DHCP server does not depend on the headquarters’ DHCP server. There is no
backup mechanism between the servers. The branch DHCP server operates continually
regardless of the status of the centralized DHCP server or the WAN link.
By default, the DHCP server is inactive. Before activating DHCP server, you configure DHCP
pools to define ranges of IP addresses and other network configuration information to be
assigned to clients. Create a minimum of two dynamic pools: at least one pool for data devices
(PCs) and at least one pool for voice devices (IP phones). The G250/G350 also supports
reservation pools, which map hardware addresses/client identifiers to specific IP addresses.
Reservation pools may be required for security issues or VPN appliances.
Overlap between pools is not allowed. You cannot configure a reservation pool on an
IP address that falls within the range of another pool.