Dhcp Server Planning - Avaya Communication Server 1000 Installation And Commissioning Manual

Planning

DHCP server planning

The handset IP-related parameters can be configured manually or through a DHCP server
(RFC 1541 and RFC 1533). Any DHCP server can be used, but it must support the following
capabilities.
• Provide Client IP address
• DHCP Option 1—Subnet Mask
• DHCP Option 3—Default Gateway
• DHCP Option 60—Class Identifier. The wireless handsets use the Class Identifier of
Nortel-221x-A or Nortel-61xx-A. The DHCP server can use the string in the Class Identifier
to uniquely identify a wireless handset.
• DHCP Option 66. This can be used to specify the address of the TFTP Server. If this
option is not configured, the wireless handset looks at the Next server Boot server (siaddr)
Option for the address of the TFTP Server* Vendor Specific Option 43, 128, 144, 157,
191, or 251. Only one of these options is required. The DHCP server encodes the Server 1
information using the same format as the IP Phone 2004. If the Server 2 information is
also present in the option, it is ignored.
• DHCP Option 151. This option contains the IP address of the WLAN IP Telephony
Manager 2245. If Option 151 is not configured, the wireless handset performs a DNS
lookup of the name SLNKSVP2, if Options 6 (DNS Server) and 15 (Domain Name) are
configured.
• DHCP Option 152. If an optional WLAN Application Gateway 2246 is used in the system,
its IP address can be specified with this option.
Each wireless handset effectively uses two IP addresses in the wireless subnet: one for the
physical wireless handset and a second alias IP address that is used on the WLAN IP
Telephony Manager 2245. When allocating addresses in a subnet scope on the DHCP server, a
contiguous block of IP addresses as large as the number of wireless handsets supported must
be marked as unavailable for distribution for other uses by the DHCP server.
When multiple WLANs are connected to a single Wireless Security Switch (WSS), the DHCP
server can require specific configuration modifications. For a specific WSS that is used for
special DHCP configuration requirements, see the WSS documentation.
The WLAN handsets support numerous DHCP extensions for assigning various configuration
options. The WLAN handsets supply a vendor class identifier string, which in this case is
Nortel-221x-A and Nortel-61xx-A. The WLAN handsets do not accept these options from the
DHCP server encapsulated in a 43 Vendor Type option (which is the normal way vendor
classes work). Consequently, you do not define these options as part of a vendor class on the
DHCP server. Instead, you define them as new options that are assigned using the native code
numbers that you give them.
46 Avaya WLAN IP Telephony Installation and Commissioning November 2010