Subject: [Capwap] JOIN-to-DISCOVERY vs JOIN-to-RESET transitions

From: "Filippo Giordano" <[email-masked]>
Date: Fri, 18 Aug 2006 17:07:42 +0200

Hello,
I'm a student. I'm studing Telecommunication engineering in Palermo.
I have read the CAPWAP protocol Specification, draft 02.
It's not clear for me the difference between the causes that generates the state transitions JOIN-to-DISCOVERY and those that generates the JOIN-to-RESET.
Both transitions occur when the WTP WaitJoin Timer expires. So, what transition it will occur when the WTP WaitJoin Timer expires if the WTP is in the JOIN state?
Moreover, maybe I'm in error, but I don't agree the AC Descriptor Message Element to be of 18 bytes. Please, there is someone who can explain to me why these 18 bytes?
The Radio Administrative State Message element, too, is 3 bytes of length and not 2 as the draft reports.
Thanks ahead of time.

Filippo Giordano

_________________________________________________________________
To unsubscribe or modify your subscription options, please visit:
http://lists.frascone.com/mailman/listinfo/capwap

Archives: http://lists.frascone.com/pipermail/capwap

---

From: Scott G Kelly <[email-masked]>
Date: Sat, 19 Aug 2006 09:34:30 -0700

Hi Filippo,

Filippo Giordano wrote:
> It's not clear for me the difference between the causes that generates 
> the state transitions JOIN-to-DISCOVERY and those that generates the 
> JOIN-to-RESET.
> Both transitions occur when the WTP WaitJoin Timer expires. So, what 
> transition it will occur when the WTP WaitJoin Timer expires if the WTP 
> is in the JOIN state?

In the current state diagram, JOIN is a meta-state that encompasses the 
DTLS handshake along with a joinreq/joinrsp exchange that occurs once 
the handshake is complete and the DTLS session is established. There has 
been some discussion of modifying this in the next rev of the draft, but 
  here's the answer to your question with respect to the 02 draft's 
state machine: The first thing the WTP does upon entering this state is 
send a DTLS ClientHello message. If the AC does not respond to this 
message, no "session" has been established, so rather than going into 
RESET, the WTP simply returns to DISCOVERY.

I think we'll see state machine clarifications in the 03 draft revision.

Scott