Default Configurations - Nortel BCM50 Configuration Manual

478 Chapter 65 DHCP overview
For example, the BCM LAN IP address, S1 and S2 IP address were all set to 47.166.50.80. When
the BCM LAN IP address is changed to a static IP address 47.166.50.114, the S1 and S2 IP
addresses also change to 46.166.50.114. If the S1 or S2 IP addresses was set manually and is
different from the BCM customer LAN address, these addresses will not be updated.
DHCP server on BCM50a and BCM50e
The BCM50a and BCM50e include a router with a DHCP server. By default, this DHCP server
will provide a dynamic IP address to the BCM Customer LAN. The embedded router will
recognize the MAC address of the BCM and reserve an IP address (192.168.1.2 is the default
address).
When the BCM requests a dynamic IP address, the embedded router sends the reserved IP address,
and disables the DHCP server on the BCM.
The embedded router supplies DHCP information as well as the vendor information for IP sets. If
the reserved IP address for the BCM matches the S1 or S2 address and is changed, the VoIP
information changes as well. If the S1 or S2 IP address have been set manually and are different
from the BCM address, these addresses are not updated.
For example, a system has a BCM LAN IP address of 47.166.50.108, an S1 IP address of
47.50.22.34, and an S2 IP address of 47.166.50.108. If the BCM LAN IP address is changed, the
S2 IP address changes as well, because it had matched the BCM LAN IP address. The S1 IP
address does not change, because it had been set manually.
Whenever the BCM LAN IP address changes, the IP sets eventually detect this and reset
themselves if they are using DHCP. If they are manually configured, then each set must be
re-configured to point to the new BCM IP address. They will get the new VoIP information from
the embedded router, which provides them with the new IP address for the BCM.

Default configurations

The DHCP component is designed with an automatic configuration that should work in most
environments.
If the BCM includes a router, the router is by default the DHCP Server.
The core module is by default a DHCP client. It attempts to obtain its IP address over DHCP.
The core module DHCP Server setting is by default set to 'automatic'. The result of the DHCP
client's request determines the functionality of the DHCP Server.
If it is successful in obtaining an IP address, the BCM turns on its DHCP Server to supply
addresses to IP sets only. It will ignore DHCP requests from other IP devices, allowing those
requests to be handled by the other DHCP Server on the network.
If it is unsuccessful in obtaining an IP address, the BCM turns off its DHCP client, and turns on its
DHCP Server to supply addresses to all devices that request IP addresses.
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