AT+i Programmer's Manual - SE Spezial-Electronic AG
AT+i Programmer's Manual - SE Spezial-Electronic AG
AT+i Programmer's Manual - SE Spezial-Electronic AG
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
17 DHCP Client<br />
DHCP Client<br />
A DHCP client component in iChip in LAN mode supports IP and server name<br />
acquisition from a standard DHCP Server. The iChip device attempts to contact and<br />
acquire server names from a DHCP server if and when its DIP (Default IP) parameter<br />
contains the special value 0.0.0.0.<br />
When the DHCP acquisition procedure is successful, the iChip‘s IPA (IP Address)<br />
parameter contains the assigned IP address retrieved from the DHCP server. In addition,<br />
server names relevant to iChip parameters are retrieved from the DHCP server, if and<br />
only if they contain empty values at power-up (see table below). Parameters that contain<br />
non-empty values retain those values. In addition, DNS values retrieved from the DHCP<br />
server are retained as additional alternative DNS addresses when DNSn contain userdefined<br />
values.<br />
Parameter Name Function Empty Value<br />
IPG Gateway 0.0.0.0<br />
SNET Subnet Mask 0.0.0.0<br />
DNS1 Primary Domain Name Server 0.0.0.0<br />
DNS2 Secondary Domain Name Server 0.0.0.0<br />
SMTP Email Send Server ‗‘ (Empty String)<br />
POP3 Email Receive Server ‗‘ (Empty String)<br />
Table 17-1: Server Names Acquired from DHCP Server<br />
All values acquired from the DHCP server are not retained as nonvolatile values. New<br />
values shall be acquired during the next DHCP session, which will be activated during<br />
the next iChip power-up, following a soft or hard reset or after the DHCP lease expires.<br />
The DHCP client has two associated points in time when the DHCP server is contacted<br />
for additional negotiations. At T1 (usually after half the original lease period), iChip<br />
attempts to renew the lease period. If the renewal procedure fails, at T2 (usually after 7/8<br />
the original lease period) iChip attempts to re-negotiate the lease. If the procedures at T1<br />
and T2 fail and the lease expires, iChip continuously tries to locate a DHCP server for renegotiation.<br />
When this is the case, iChip stores 0.0.0.0 in the IPA parameter and cannot<br />
communicate on the LAN until a DHCP server is found and IP and server names are<br />
acquired.<br />
<strong>AT+i</strong> Programmer‘s <strong>Manual</strong> Version 8.21 17-1
Change language