H3C Technologies H3C SecPath F1000-E - Manual (Page 39)

7
Figure 8 Sub-option 1 in normal padding format
Sub-option type (0x01)
0 7 15
Length (0x06) Circuit ID type (0x00) Length (0x04)
23 31
VLAN ID Interface number
• Sub-option 2: Padded with the MAC address of the DHCP relay agent interface that received the
client’s request. The following figure gives its format. The value of the sub-option type is 2, and that
of the remote ID type is 0.
Figure 9 Sub-option 2 in normal padding format
2. Verbose padding format
The padding contents for sub-options in the verbose padding format are as follows:
• Sub-option 1: Padded with the user-specified access node identifier (ID of the device that adds
Option 82 in DHCP messages), and the type, number, and VLAN ID of the interface that received
the client’s request. Its format is shown in Figure 10 .
Figure 10 Sub-option 1 in verbose padding format
NOTE:
In Figure 10 , except that the VLAN ID field has a fixed length of 2 bytes, all the other padding contents of
sub-option 1 are length variable.
• Sub-option 2: Padded with the MAC address of the DHCP relay agent interface that received the
client’s request. It has the same format as that in normal padding format, as shown in
Figure 9 .
Option 184
Option 184 is a reserved option, and parameters in the option can be defined as needed. The device
supports Option 184 carrying the voice related parameters, so a DHCP client with voice functions can
get an IP address along with specified voice parameters from the DHCP server.
Option 184 involves the following sub-options:
• Sub-option 1: IP address of the primary network calling processor, which is a server serving as the
network calling control source and providing program downloads.
• Sub-option 2: IP address of the backup network calling processor that DHCP clients will contact
when the primary one is unreachable or invalid.
• Sub-option 3: Voice VLAN ID and the result whether DHCP clients take this ID as the voice VLAN or
not.