Re: Multiple SCTP associations

Tolga, Ilie,
thank you for your valuable replies on the subject!

Please let me know, if I misinterpreted your answers.

1.
As far as I understand it, an SCTP endpoint, to say it strictly, may have 
only one SCTP association; and a signaling process may use multiple SCTP 
endpoints (and hence multiple SCTP associations) for communication with 
different signaling processes of one AS/SG.

2.
Multiple SCTP associations between the same two signaling processes, while 
not prohibited, will require reinterpretation of SCTP-to-ULP events (to keep 
communication status and ASP states consistent across multiple SCTP 
associations), such as NETWORK STATUS CHANGE, COMMUNICATION UP/LOST/ERROR, 
RESTART and SHUTDOWN COMPLETE events (RFC2960).


Regards,
Sergey Mikhailov.



----- Original Message ----- 
From: "Tolga Asveren" <[email protected]>
To: <[email protected]>
Sent: Tuesday, January 10, 2006 7:33 PM
Subject: RE: [Sigtran] Multiple SCTP associations


> Sergey,
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]On Behalf
> Of
> Sergey Mikhailov
> Sent: Tuesday, January 10, 2006 11:39 AM
> To: SIGTRAN
> Subject: [Sigtran] Multiple SCTP associations
>
>
> Hi,
>
> It seems that multiple SCTP associations established between the same two
> signaling processes are not [explicitly] prohibited.
>
> 1.
> Is it legal for a signaling process to establish more than one SCTP
> association to the same AS/SG where these multiple associations are served
> by different signaling processes?
> [TOLGA]Yes, this is how host redundancy is achieved (I assume you talk
> about
> M3UA/SUA). There are multiple ASPs serving an AS, and multiple SGPs in a
> SG,
> and there is a SCTP association between each SGP/ASP pair -well, obviously
> it is not mandatory-.
>
> 2.
> Is it legal for a signaling process to establish more than one SCTP
> association to the same signaling process at the remote side?
>
> (I feel that the 2nd case may be reasonable only when the remote side does
> not support multi-homed SCTP endpoints.)
> [TOLGA]Multiple SCTP assocaitions between two etities will have problems
> with ASP state machine if you follow it strictly considering the state
> transitions associated with events from SCTP. This is easy to overcome
> with
> a some reasonable reinterpretation. OTOH, multiple SCTP associations won't
> be a replacement for SCTP multihoming support because SCTP multihoming
> provided network/NIC redundancy without loss/missequencing of messages.
>
> Regards,
> Sergey Mikhailov.
>
>
>
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