Alcatel-Lucent 6850-48 网络指南
DHCP Relay Implementation
Configuring DHCP Relay
page 31-10
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
To delete an IP address, use the no form of the
this syntax will be deleted. If an IP address is not specified with this syntax, then all IP helper addresses
are deleted. The following command deletes a helper address for IP address 125.255.17.11:
are deleted. The following command deletes a helper address for IP address 125.255.17.11:
-> ip helper no address 125.255.17.11
The following command deletes all IP helper addresses:
-> ip helper no address
Configuring BOOTP/DHCP Relay Parameters
Once the IP address of the DHCP server(s) is defined and the DHCP Relay is configured for either Global
DHCP request or Per-VLAN DHCP request, you can set the following optional parameter values to
configure BOOTP relay.
DHCP request or Per-VLAN DHCP request, you can set the following optional parameter values to
configure BOOTP relay.
• The forward delay time.
• The hop count.
• The relay forwarding option.
The only parameter that is required for BOOTP relay is the IP address to the DHCP server or to the next
hop to the DHCP server. The default values can be accepted for forward delay, hop count, and relay
forwarding option.
hop to the DHCP server. The default values can be accepted for forward delay, hop count, and relay
forwarding option.
Alternately the relay function may be provided by an external router connected to the switch; in this case,
the relay would be configured on the external router.
the relay would be configured on the external router.
Setting the Forward Delay
Forward Delay is a time period that gives the local server a chance to respond to a client before the relay
forwards it further out in the network.
forwards it further out in the network.
The UDP packet that the client sends contains the elapsed boot time. This is the amount of time, measured
in seconds, since the client last booted. DHCP Relay will not process the packet unless the client’s elapsed
boot time value is equal to or greater than the configured value of the forward delay time. If a packet
contains an elapsed boot time value that is less than the specified forward delay time value, DHCP Relay
discards the packet.
in seconds, since the client last booted. DHCP Relay will not process the packet unless the client’s elapsed
boot time value is equal to or greater than the configured value of the forward delay time. If a packet
contains an elapsed boot time value that is less than the specified forward delay time value, DHCP Relay
discards the packet.
The forward delay time value applies to all defined IP helper addresses. The following command sets the
forward delay value of 10 seconds:
forward delay value of 10 seconds:
-> ip helper forward delay 10
The range for the forward delay time value is 0 to 65535 seconds.