DHCP信息 The client sends a request to the DHCP server: either to request more information than the server sent with the original DHCPACK; or to repeat data for a particular application - for example, browsers use DHCP Inform to obtain web proxy settings via WPAD. Such queries do not cause the DHCP server to refresh the IP expiry time in its database.
DHCP释放 The client sends a request to the DHCP server to release the DHCP and the client unconfigures its IP address. As clients usually do not know when users may unplug them from the network, the protocol does not mandate the sending of DHCP Release.
客户配置参数 A DHCP server can provide optional configuration parameters to the client. RFC 2132 describes the available DHCP options defined by Internet Assigned Numbers Authority (IANA) - DHCP and BOOTP PARAMETERS.
Options DHCP Option 60 is an option for specifying the Vendor Class Identifier. Within the DHCP there is default route. Option60 is the Vendor ID. Based on this option, you can make special decisions on the CPE to treat the STB. The biggest benefit with using DHCP option 60 is that you do not need to define a port to be bridge or router. Bridging is based on the MAC address of the option 60 so a switch could be connected to the SE567 and have both PC&＃39;&＃39;s and STB&＃39;&＃39;s on a single interface. Option 60 can be used by DHCP clients to identify the vendor and functionality of a DHCP client. The information is a variable length string of characters or octets which has a meaning specified by the vendor of the DHCP client. One method that a DHCP client can communicate that it is using a certain type of hardware or firmware, is to set a value in its DHCP requests called the Vendor Class Identifier (VCI) (Option 60). This method has a DHCP server differentiate between the two kinds of CMs and process the requests from the two types of modems appropriately. Some types of set-top boxes also set the VCI (Option 60) to inform the DHCP server about the hardware type and functionality of the device. The value that this option is set to gives the DHCP server a hint about any required extra information that this client needs in a DHCP response.