The Dhcp Negotiation Process - Nokia ESB26 User Manual

19.
The No IP Error Scenario
The above behavior of the DHCP client assumes that it has successfully received an IP
address from the DHCP server. If, however, the IP address has not been received, the DHCP
client will keep re-sending the request at predefined time intervals until it eventually manages
to negotiate an IP address. (For the exact behavior of the DHCP client and managing its
retransmission timeout, refer to Changing the DHCPDISCOVER Messages Retransmission
Timeout chapter.)
NOTES
1. The DHCP client is toggled on/off with the (no) ip address dhcp command.
2. You can choose whether to save the downloaded configuration to the non-volatile
memory. This is managed with the dhcp-client save-config command.
For details on these commands, refer to Configuring the DHCP Client chapter.
The entrire startup process is schematically presented in Figure 19-2. It uses asterisks (*), to
indicate the following:
*
**
****

The DHCP Negotiation Process

As shown in Table 19-1, the parameter negotiation starts with a DHCPDISCOVER broadcast
message from the client seeking a DHCP server. The DHCP Server responds with a
DHCPOFFER unicast message offering configuration parameters (such as an IP address, a
MAC address, a domain name, and a lease for the IP address) to the client. The client returns
a DHCPREQUEST broadcast message requesting the offered IP address from the DHCP
Server. The DHCP Server responds with a DHCPACK unicast message confirming that the IP
address has been allocated to the client.
Figure 19-1 Obtaining an IP Address from a DHCP Server
MN700004 Rev 01
DHCP Client
This configuration is saved to the non-volatile memory;
File consistency is tested by a check-sum algorithm;
This means that there is no startup configuration file.
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