User Guide

TD-W8968 300Mbps Wireless N USB ADSL2+ Modem Router User Guide

Figure 4-13

¾ Obtain an IP address automatically: Select this option, the modem router will be able to

obtain IP network information dynamically from a DHCP server provided by your ISP.

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Note:

1) The response message from a DHCP server typically contains a number of configuration

parameters (DHCP options) for the modem router. The DHCP options include IP network

information, and also the vendor-specific options. In some cases, the modem router is

implemented to perform user-defined operations (as shown below). You can implement your

own treatment of all such options.

2) If the modem router is functioning as a DHCP client, it must identify itself in option 61

(client-identifier) in every DHCP message. DUID/IAID is portion of option 61.

• Option 60 Vendor ID: The option code 60 used to identify Vendor class.

• Option 61 IAID: IAID (Identity Association ID) assigns an Identity Association ID to

individual interfaces. In cases where the device is functioning with a single DHCP client

identity, it must use value 1 for IAID for all DHCP interactions. In cases where the device

is functioning with multiple DHCP client identities, the values of IAID have to start at 1 for

the first identity and be incremented for each subsequent identity. For example, the

device may use IAID value 1 for the first physical interface and value 2 for the second.

Alternatively, the device may use IAID value 1 for the virtual circuit corresponding to the

first connection object in the data model and value 2 for the second connection object in

the data model.

• Option 61 DUID: Specifies the name of the interface whose link-layer address the server

is to use as its DUID (DHCP Unique Identifier). You must enter a value for this parameter

or the server will not start. When the server starts, the DUID is written to the system log.

• Option 125: The option 125 allows DHCP server to be pre-configured with policy for

handling classes of devices in a certain way without requiring DHCP server to be able to

parse the unique format used in client-identifier option.

¾ Use the following Static IP address: If you are provided with a static IP/gateway Address,

please select this option, and then enter the WAN IP Address, WAN Subnet Mask and WAN

gateway IP Address manually.