Re: Minimum Number of Streams in SCTP

Aditya,

SCTP can not make such a requirement because it is a general purpose  
transport
protocol not specific designed for M3UA.

So it is up to the upper layer to request setting up an association  
with the
appropriate number of streams and check if the requirements are  
fulfilled after
the association has been set up. If the upper layer needs more  
streams he
only can turn down the association. So if you run M3UA and want to  
send DATA
messages you need more than one stream. From
http://www.ietf.org/internet-drafts/draft-ietf-sigtran-rfc3332bis-06.txt

    1. DATA message MUST NOT be sent on stream 0.
    2. ASPSM, MGMT, RKM  classes SHOULD be sent on stream 0 (Other than
       BEAT, BEAT ACK and NTFY messages)
    3. SSNM, ASPTM classes and BEAT, BEAT ACK and NTFY messages can be
       sent on any stream.

Only if you do not want to send DATA messages one stream would be  
enough.

Best regards
Michael

On Aug 7, 2006, at 9:26 AM, Aditya wrote:

> What about the specific case of M3UA running over SCTP. M3UA does  
> not allow data messages to be sent over stream 0. However, there is  
> no mention in either RFC's (M3UA or SCTP) about the minimum number  
> of streams to be opened. My question was strictly for M3UA over  
> SCTP. The implementation I work on rejects associations with  
> streams less than 2. However,  I found no support for this  
> behaviour in the RFC.
>
> Ashish Soregaonkar <[email protected]> wrote: Is this not  
> an inconsistency among the UA's then? I dont see why M3UA should  
> not allow data transmission on stream '0', if the number of  
> negotiated streams is 1. If not then RFC 3332 should mention that  
> the number of streams to be used should always be >1.
>
> -Ashish
>
> On 8/5/06, Saurabh Jain <[email protected]> wrote:
> Hi Aditya,
> The statement that "DATA message cannot be sent on stream 0" is not  
> true for all UA's. For example
>
> M3UA 3332:
> 4.1.1 Receipt of Primitives from the M3UA-User
> DATA messages MUST be sent on an SCTP stream other than stream '0'.
>
> SUA 3868:
> 4.1.1.  Receipt of Primitives from SCCP
> DATA messages MUST be sent on an SCTP stream other than stream '0'  
> when there is more than one stream.
>
> Thus SUA does allow sending DATA on Stream 0, if there is only one  
> stream.
>
> rgds
> Saurabh
>
> On 8/5/06, Aditya < [email protected]> wrote:
> Does SCTP RFC specify the minimum no. of strems that must be  
> opened. If not, then what happens if there is only one stream  
> negoitated (i.e stream id 0). DATA message cannot be sent on stream  
> 0. This leads me to think that there must be atleast two streams.  
> Any references in the RFC, pls quote.
>
> Thanks in advance,
> Aditya
>
>
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