Re: Loadsharing based on SLS in SUA

amrita.garg,

Yes, but sequence control does not have a one to one mapping to SLS: it
has a many to one mapping.

--brian

[email protected] wrote:                                   (Thu, 15 Dec 2005 15:04:01)
> 
>    Hi,
> 
> 
>    Since  SLS  parameter  is  not  available  in  SUA layer, and Sequence
>    Control  has  a one to one mapping with SLS,  is Sequence control used
>    for "loadsharing based on SLS" in SUA.
> 
> 
> 
>    From RFC Q.714
> 
>    In  protocol  class  1, the features of class 0 are complemented by an
>    additional feature (i.e. the
> 
>    sequence   control  parameter  contained  in  the  N-UNITDATA  request
>    primitive) which allows the
> 
>    higher  layer  to  indicate  to  the SCCP that a given stream of NSDUs
>    shall be delivered in-sequence.
> 
>    The  Signalling  Link  Selection  (SLS)  parameter in the MTP-TRANSFER
>    request primitive is chosen
> 
>    by  the  originating  SCCP  based on the value of the sequence control
>    parameter. The SLS shall be
> 
>    identical  for  a  stream  of  NSDUs  with  the  same sequence control
>    parameter. The MTP then encodes
> 
>    the  Signalling Link Selection (SLS) field in the routing label of MTP
>    messages relating to such
> 
>    NSDUs,  so that their sequence is, under normal conditions, maintained
>    by the MTP and SCCP. With
> 
>    the  above  constraints,  the SCCP and MTP together ensure in-sequence
>    delivery to the user. Thus,
> 
>    this protocol class corresponds to an enhanced connectionless service,
>    where an additional
> 
>    in-sequence delivery feature is included.
> 
> 
>    From RFC 3868
> 
>    The field is coded with the value of the sequence control parameter
> 
>    associated with a group of messages and are chosen so as to ensure
> 
>    proper loadsharing of message groups over SLS values while ensuring
> 
>    that sequence control values within message groups have the sequence
> 
>    control value coded with the same value as the initial message of the
> 
>    message group.
> 
> 
>    Regards
> 
>    Amrita Garg

> _______________________________________________
> Sigtran mailing list
> [email protected]
> https://www1.ietf.org/mailman/listinfo/sigtran


-- 
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/