how to get options in bound state

[David W. Hankins]

On Sun, Feb 18, 2007 at 03:13:37PM +0530, tajinder.pal at wipro.com wrote:
> I am curious to know how a dhcp client obtains any optional parameter
> from server when it is in bound state. What will be message type for
> that? will it be DHCPREQUEST or DHCPINFORM.

If I understand you correctly, you have a client that has BOUND to
a lease, but has added a code to its parameter request list.

If it were me, I would use an early DHCPREQUEST as if in RENEWING
state.  Clients are allowed to renew early, and many do so for
example when link states fluctuate (although they typically choose
REBINDING state so that they can reach any local DHCP servers).

The only thing to be sure of (that I can think of), is that whatever
input you use to enter renew early - you make certain that it doesn't
double-trigger if it's entered while a RENEW is already in progress.

The reason is that DHCPREQUEST is the most expensive message a
DHCP server can be made to process - it requires updating permanent
storage.  So as few as you can comfortably allow.


If the client did not get its address via DHCP, then it would use
a DHCPINFORM.  It's less important to limit the rate (this is very
cheap for servers to process), but probably still a good idea.


You might want to ask questions like this, regarding the protocol
and implementation, on either the dhcp-hackers mailing list, or
the DHC WG mailing list (dhcwg at ietf.org).

-- 
David W. Hankins	"If you don't do it right the first time,
Software Engineer		you'll just have to do it again."
Internet Systems Consortium, Inc.	-- Jack T. Hankins