Alcatel-Lucent 6850-48 Reference Guide

Port Mobility Commands

page 20-6

OmniSwitch CLI Reference Guide

Defines a DHCP port rule for an existing VLAN. If a DHCP frame is received on a mobile port that 
matches the port specified in the rule, the mobile port is temporarily assigned to the rule’s VLAN.

vlan vid dhcp port slot/port

vlan vid no dhcp port slot/port

VLAN ID number (1–4094).

The slot number for the module and the physical mobile port number on 
that module (e.g., 3/1 specifies port 1 on slot 3). To enter multiple slots 
and ports in a single command, use a hyphen to specify a range of ports 
(e.g., 3/1-16) and a space to specify multiple slots (e.g., 3/1-16 5/10-20 
8/2-9).

N/A

OmniSwitch 6400, 6850, 6855, 9000, 9000E

• Use the no form of this command to delete a DHCP port rule from the specified VLAN.

• Port mobility software checks for and processes DHCP traffic first on an active mobile port. When a 

mobile port receives a DHCP frame that matches a DHCP rule, the port is temporarily assigned to the 
VLAN long enough to forward the DHCP requests within the VLAN broadcast domain. The source 
MAC address of the DHCP frame, however, is not learned for that VLAN port association.

• Once a DHCP device has obtained an IP address, its non-DHCP traffic must match other VLAN rules 

within the same VLAN for the device to remain a member of that VLAN. If this match occurs, then the 
frame source is learned in the matching rule VLAN.

• DHCP rules are most often used in combination with IP network address rules. A DHCP client has an 

IP address of all zeros (0.0.0.0) until it receives an IP address from a DHCP server, so it would not 
match any IP network address rules. 

• Binding rules, MAC address rules, and protocol rules also capture DHCP client traffic. The exception 

to this is binding rules that specify an IP address as part of the rule, similar to IP network address rule 
definitions.

• Rules are only assigned to existing VLANs. Use the vlan command to create a new VLAN.