[Dibbler] Question about Conform message

Tomasz Mrugalski thomson at klub.com.pl
Wed May 23 15:31:58 CEST 2007


On Wed, 23 May 2007 somebody known as Hideshi.Enokihara at jp.yokogawa.com wrote:

> I have a simple question.
> Do you have any plans to support sending Confirm message from a dibbler
> clinet?
Unfortunately, CONFIRM message will not be supported in a near future. 
Theere are several reasons:

1. CONFIRM must be sent every time link is switched (802.11 handover, 
Ethernet replugged, etc.). I don't know how to detect such point of 
attachement changes. What's more, there has to be defined uniform 
mechanism, so similar approach will be possibile on all platforms, 
including Windows.

2. CONFIRM could also be sent after recovery from a crash (power outage, 
system or dibbler crash etc). So to make this work, client would have to 
detect if its previous instance had shutdown properly or not. (Well, it's 
not that hard, it would have to investigate client-AddrMgr.xml only) and 
then send CONFIRM.

3. I believe scenario 2 is not very useful, bucause the same effect can be 
achieved with clever server logic. Starting from 0.6.0 release, 
if the dibbler-server has already exisisting binding for a client and 
receives REQUEST (i.e. client after crash sends new REQUEST), it will send 
this already bound address, not the new one. That operation has changed 
since previous versions.

So here is your answer. I'm afraid that is not what you'd like to hear.
I will implement support for CONFIRM eventually, but it's one of the last 
entries on my TODO list.

On the other hand, if your company needs this feature, we can work 
something out. I could provide assistance if you want to implement this on 
your own. There are also other ways possible.

Best regards,
-- 
Tomasz Mrugalski,              | "I think there is a world market for     |
thomson(at)klub(dot)com(dot)pl |  about five computers."                  |
                                |     Thomas J. Watson (Chairman, IBM) 1943|


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