H3C Technologies H3C S12500 Series Switches - Manual (Page 46)

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Figure 25 Sub-option 9 in Private padding format
4. Standard padding format
{
Sub-option 1—Contains the VLAN ID of the interface that received the client's request, module
(subcard number of the receiving port on a centralized device or slot number of the receiving
port on a distributed device) and port (port number of the receiving port). The value of the
sub-option type is 1, and the value of the circuit ID type is 0.
Figure 26 Sub-option 1 in standard padding format
{
Sub-option 2—Contains the MAC address of the DHCP relay agent interface or the MAC
address of the DHCP snooping device that received the client's request. The value of the
sub-option type is 2, and that of the remote ID type is 0. It has the same format as sub-option 2
in normal padding format. See Figure 21 .
Option 184
Option 184 is a reserved option, and parameters in the option can be defined as needed. The switch
supports Option 184 carrying 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 serves as the network
calling control source and provides program downloads.
• Sub-option 2—IP address of the backup network calling processor that DHCP clients will contact
when the primary one is unreachable.
• Sub-option 3—Voice VLAN ID and the result whether DHCP clients take this ID as the voice VLAN
or not.
• Sub-option 4—Failover route that specifies the destination IP address and the called number (SIP
users use such IP addresses and numbers to communicate with each other) that a SIP user uses to
reach another SIP user when both the primary and backup calling processors are unreachable.
NOTE:
For Option 184, you must define sub-option 1 to make other sub-options take effect.
Protocols and standards
• RFC 2131, Dynamic Host Configuration Protocol