During the configuration discovery stage, the DHCP server receives the DHCP DISCOVER message and replies with a DHCP OFFER message that contains an IP address assigned to the network interface. Table: DHCP OFFER Message Options describes the options included in the DHCP OFFER. If any of the required options are not included, the packet may be dropped and not processed.
Option |
Name |
Description |
Required |
|---|---|---|---|
yiaddr |
Client Ip-Address |
The network interface IP address For network consistency, it is recommended that this IP address be a fixed IP address, not assigned randomly from a DHCP server IP pool |
Yes |
1 |
Subnet Mask |
The network interface subnet mask |
Yes |
3 |
Router |
The network interface default gateway Only the first router is used – all others are ignored |
No |
12 |
Host Name |
The network interface hostname |
No |
51 |
Lease Time |
The least time, validated as infinite |
Yes |
54 |
Server Address |
Identifies the DHCP server |
No |
67 |
Bootfile Name |
Contains the ADP instructions or a URL to an ADP instructions file |
No |
DHCP OFFER messages are not dropped if they contain a yiaddr that does not match the local configured subnets on the DHCP relay interface. This applies only to regular IES and VPRN interfaces with no lease-populate configured on the DHCP relay interface.
Option 67 contains further configuration information in the form of keyword text files interpreted by ADP as instructions and executed during the Configuration and Test phases. For basic reachability, option 67 is not mandatory; however, it can be used to send the system IP address of a newly discovered node, making it possible to communicate with the NSP NFM-P and complete ADP.
If a system IP address is made available with the DHCP OFFER and a template configuration file is also executed using the load-cfg keyword, then the system IP address specified in the template configuration file is used instead of the one in the DHCP OFFER.
Table: ADP Instructions describes the keywords used in ADP instructions. A DHCP offer message can contain a maximum of 15 instructions in either the Bootfile Name option, or in an external file referenced by the include keyword. If more than 15 instructions are included, ADP fails to complete and the system generates an error message in the ADP log.
Keyword |
Description |
Format |
|---|---|---|
sys-addr |
Specifies the system interface IP address and the system base routing instance subnet |
sys-addr 10.10.10.1/32 |
sys-name |
Specifies the chassis name |
sys-name SITE43_7705 |
sys-loc |
Specifies the chassis location |
sys-loc 600_MARCH_ROAD |
load-cfg |
Specifies the URL of a template configuration file to load into the router's runtime configuration |
load-cfg ftp://.....@.../7705.cfg |
test-ip |
Specifies an IP address that must be successfully pinged before committing configuration and declaring ADP a success |
test-ip 192.20.2.30 |
include |
Specifies the URL of a file containing additional ADP instructions |
include ftp://.....@.../7705.tmp |
Any BOF keyword |
Interpreted as instructions to update the specified field in the BOF |
As per BOF |