Avaya 1230 - Multiple DHCP Servers

DHCP Option Description
Router Option 3
Domain Name Server 6 Accepts the first two DNS addresses.
Domain Name 15
Broadcast Address 28 This is the broadcast address of the subnet. The IP
Deskphone automatically calculates the broadcast
address if it is not provided.
Vendor Specific Option 43
DHCP Renewal Time 58
DHCP Rebinding Time 59
TFTP Server Name 66 Two forms of the server name are supported. If a
dotted-decimal IP address is returned, it is assumed
to point to a TFTP server. A full URL can also be
provided to specify a protocol and FQDN.
Old Site Specific Options 128, 131, 144, 157,
188, 191, 205, 219,
223
Options are supported, but not recommended for new
installations. These options are reclaimed according
to RFC 3942.
Site Specific Options 224, 227, 230, 232,
235, 238, 241, 244,
247, 249, 251, 254
New site specific options which are recommended to
be used.
The Vendor (43) or site specific options allows a vendor-encapsulated or site-specific option (or
both) to transport the “Nortel-SIP-Phone-B” option string with auto-provisioning parameters to the IP
Deskphone. The administrator must use one of the site-specific or vendor-encapsulated option
codes; the method used depends on the DHCP server's capabilities and what options are already in
use for other vendor devices.
Multiple DHCP Servers
It is possible that two or more DHCP servers can respond to the DHCP Discover message. When
the IP Deskphone sends a Discover message, it waits for 1 second to collect all the responses. If
there is more than one response, the IP Deskphone selects the response with the longest lease
time. If the lease time is identical, the first response is selected.
Configure the DHCP server to support SIP IP Deskphone
class identifier
After the DHCP server is configured to recognize the IP Deskphone with SIP Software as a unique
IP Deskphone, the DHCP server can treat the IP Deskphone differently than other DHCP
Multiple DHCP Servers
March 2015 SIP Software for Avaya 1200 Series IP Deskphones-Administration 105
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