Cisco IE-4000 Software Configuration Manual page 396

Configuring DHCP
Information About Configuring DHCP
— Length of the remote-ID type
In the port field of the circuit-ID suboption, the port numbers start at 3.
for the remote-ID suboption and the circuit-ID suboption when the default suboption configuration is used. The switch
uses the packet formats when you globally enable DHCP snooping and enter the ip dhcp snooping information option
global configuration command.
Figure 61 Suboption Packet Formats
Circuit ID Suboption Frame Format
Suboption
type
1 byte
Remote ID Suboption Frame Format
Suboption
type
1 byte
on page 393 shows the packet formats for user-configured remote-ID and circuit-ID suboptions The switch uses these
packet formats when DHCP snooping is globally enabled and when the ip dhcp snooping information option format
remote-id global configuration command and the ip dhcp snooping vlan information option format-type circuit-id
string interface configuration command are entered.
The values for these fields in the packets change from the default values when you configure the remote-ID and circuit-ID
suboptions:

Circuit-ID suboption fields
— The circuit-ID type is 1.
— The length values are variable, depending on the length of the string that you configure.

Remote-ID suboption fields
— The remote-ID type is 1.
— The length values are variable, depending on the length of the string that you configure.
Circuit
ID type
Length Length
1 6 0 4
1 byte 1 byte 1 byte
Remote
ID type
Length Length
2 8 0 6
1 byte 1 byte 1 byte
Figure 61 on page 392
VLAN Module Port
2 bytes 1 byte 1 byte
MAC address
6 bytes
392
shows the packet formats