Re: [Sigtran] [M3UA] IPSP receiving ASP ACTIVE Ack

[Santhana <santhana at huawei.com>]

Hi Brian
	Then for unsolicited "ASP ACTIVE Ack" message are the following
responses ok in SE mode.

=====================================
PRESENT STATE	ACTION
=====================================
ACTIVE		No Action
INACTIVE		Send ERROR "Unexpected"
=====================================

Regards
Santhanakrishnan


-----Original Message-----
From: Brian F. G. Bidulock [mailto:bidulock at openss7.org] 
Sent: Friday, July 10, 2009 12:30 PM
To: Santhana
Cc: sigtran at ietf.org
Subject: Re: [Sigtran] [M3UA] IPSP receiving ASP ACTIVE Ack

Santhana,

That sentence says that when you receive an ASP Active Ack that you
_MAY_ set the _PEER_ state to active, not the receiving ASP's _OWN_
state.

Now, true, in SE mode they are the same thing, but in DE mode they
are not.  For SE mode, there is no point in sending an unsolicited
ASP Active Ack because the AS can be activated simply using the ASP
Active.

Nevertheless, the normal reponse of ASPs to unsolicited messages is
to note the state and return the state to the management requested
state.  That is, an ASP or IPSP receiving an unsolicited ASP Acitve
Ack in the (DE peer) inactive state, would note that the peer believes
that the AS is active and then take the actions necessary to return
the state to the management desired state: i.e., issue an ASP Inactive
for the RC.  So, in practical terms, one cannot use the ASP Active
Ack message in an unsolicited way to activate the peer.

The reason for the response to what might appear to be an unsolicited
ASP Active Ack message is the procedure permitting retransmission of
the ASP Active (even though SCTP is reliable).  This means that
several identical ASP Active messages may appear at the peer and be
responded to with multiple ASP Activ Ack messages.

--brian

Santhana wrote:                            (Fri, 10 Jul 2009 10:14:52)
> 
>    Hi Brian
> 
>          The second sentence(quoted) in this para. I broke the two
>    sentences before interpretation as the first sentence describes IPSP
>    and the second sentence describes ASP.
> 
> 
>    It is from M3UA RFC 4666 In section 4.3.4.3.1
> 
>            Either of the IPSPs can initiate communication.  When an IPSP
> 
>       receives an ASP Active, it should mark the peer as ASP-ACTIVE and
> 
>       return an ASP Active Ack message.  "An ASP receiving an ASP Active
>    Ack
> 
>       message may mark the peer as ASP-Active, if it is not already in
>    the
> 
>       ASP-ACTIVE state."
> 
>     
> 
>    My Question applies for an ASP(and inturn IPSP) receiving an ACTIVE
>    ACK.
> 
>     
> 
>    Regards
> 
>    Santhanakrishnan
> 
> 
>    -----Original Message-----
>    From: Brian F. G. Bidulock [mailto:bidulock at openss7.org]
>    Sent: Thursday, July 09, 2009 6:00 PM
>    To: Santhana
>    Cc: sigtran at ietf.org
>    Subject: Re: [Sigtran] [M3UA] IPSP receiving ASP ACTIVE Ack
> 
> 
>    Santhana,
> 
> 
>    Santhana wrote:                            (Thu, 09 Jul 2009 17:09:25)
> 
>    >                The M3UA RFC says when an IPSP(in INACTIVE STATE)
>    receives
> 
>    >    an ASP ACTIVE Ack, it has to change the state to ACTIVE. Is this
> 
>    >    applicable even when the IPSP has not sent the ASP ACTIVE before
>    also.
> 
> 
>    Where does it say that?
> 
> 
>    --brian
> 
> 
>    --
> 
>    Brian F. G. Bidulock
> 
>    bidulock at openss7.org
> 
>    http://www.openss7.org/

-- 
Brian F. G. Bidulock
bidulock at openss7.org
http://www.openss7.org/