Ip Dhcp Snooping Information Option Circuit-Id; Table 96: Option 82 Information - Edge-Core ECS4810-12M Layer 2 Management Manual

This command specifies DHCP Option 82 circuit-id suboption information.
ip dhcp snooping
Use the no form to disable this feature.
information option
circuit-id
S
D
VLAN-Unit-Port
C
Interface Configuration (Ethernet, Port Channel)
C
◆
◆
YNTAX
ip dhcp snooping information option circuit-id string string
no dhcp snooping information option circuit-id
string - An arbitrary string inserted into the circuit identifier field.
(Range: 1-32 characters)
S
EFAULT ETTING
M
OMMAND ODE
U
OMMAND SAGE
DHCP provides a relay mechanism for sending information about the
switch and its DHCP clients to the DHCP server. DHCP Option 82 allows
compatible DHCP servers to use the information when assigning IP
addresses, to set other services or policies for clients. For more
information of this process, refer to the Command Usage section under
the ip dhcp snooping information option
Option 82 information generated by the switch is based on TR-101
syntax as shown below:

Table 96: Option 82 information

82 3-69 1
opt82 opt-len sub-opt1 string-len
The circuit identifier used by this switch starts at sub-option1 and goes
to the end of the R-124 string. The R-124 string includes the following
information:
sub-type - Distinguishes different types of circuit IDs.
■
sub-length - Length of the circuit ID type
■
access node identifier - ASCII string. Default is the MAC address of
■
the switch's CPU. This field is set by the
information option
eth - The second field is the fixed string "eth"
■
slot - The slot represents the stack unit for this system.
■
port - The port which received the DHCP request. If the packet
■
arrives over a trunk, the value is the ifIndex of the trunk.
vlan - Tag of the VLAN which received the DHCP request.
■
Note that the sub-type and sub-length fields can be enabled or
disabled using the
– 895 –
C 25
HAPTER
command.
1-67 x1 x2
ip dhcp snooping
command,
ip dhcp snooping information option
| General Security Measures
DHCP Snooping
x3 x4 x5 x63
R-124 string
command.