2-12Configuring Option 184 Parameters for the Client with Voice ServiceOption 184 is a reserved option, and the information it carries can be customized. You can define foursub-options for this option after enabling the DHCP server. Thus, besides obtaining an IP address, theDHCP client with voice services can obtain voice related parameters from the DHCP address pool.Basic conceptThe four sub-options of Option 184 mainly carry information about voice. The following lists thesub-options and the carried information:z Sub-option 1: IP address of the network call processor (NCP-IP).z Sub-option 2: IP address of the alternate server (AS-IP).z Sub-option 3: Voice VLAN configuration.z Sub-option 4: Fail-over call routing.Meanings of the sub-options for Option 184Table 2-1 Meanings of the sub-options for Option 184Sub-option Feature Function NoteNCP-IP(sub-option 1)The NCP-IPsub-option carries theIP address of thenetwork call processor(NCP).The IP address of theNCP server carried bysub-option 1 of Option184 is intended foridentifying the serverserving as the networkcall controller and theserver used forapplicationdownloading.When used in Option184, this sub-optionmust be the firstsub-option, that is,sub-option 1AS-IP(sub-option 2)The AS-IP sub-optioncarries the IP addressof the alternate server(AS).The alternate NCPserver identified bysub-option 2 of Option184 acts as the backupof the NCP server. TheNCP server specifiedby this option is usedonly when the IPaddress carried by theNCP-IP sub-option isunreachable or invalid.The AS-IP sub-optiontakes effect only whensub-option 1 (that is,the NCP-IPsub-option) is definedVoice VLANConfiguration(sub-option 3)The voice VLANconfigurationsub-option carries theID of the voice VLANand the flag indicatingwhether the voiceVLAN identificationfunction is enabled.The sub-option 3 ofOption 184 comprisestwo parts:z One part carries theflag indicatingwhether the voiceVLAN identificationfunction is enabled.z The other partcarries the ID of thevoice VLAN.z A flag value of 0indicates that thevoice VLANidentificationfunction is notenabled, in whichcase theinformation carriedby the VLAN ID partwill be neglected.z A flag value of 1indicates that thevoice VLANidentificationfunction is enabled.
