The Advisory Attribute

                                                       David Kessens
                ____________________________________________________




                               The Advisory Attribute



                                   David Kessens
                                      RIPE NCC
                                 Document: ripe-131

                                Obsoletes: ripe-130
                                 Updates: ripe-181


    Scope

                This  document  describes  the advisory attribute of
                the route object.


    Description

                Some autonomous systems may  benefit  from  specific
                private  information  stored in the routing registry
                on a per route basis.  The advisory attribute of the
                route  and  aut-num objects enables this.  It simply
                provides a mechanism by which the  maintainer  of  a
                route  or  autonomous  system object can register an
                arbitrary text string intended for the operator of a
                specific  'target'  AS.  The syntax and semantics of
                the text string are defined by the operator  of  the
                'target'  AS  concerned  and are beyond the scope of
                this document.

                The advisory attribute of a route object applies  to
                the  specific  route.   The advisory attribute of an
                aut-num object is intended to apply  as  default  to
                all  routes  originated  by the autonomous system in
                question, providing a shorthand notation if the same
                advisory  applies  to  most  or all such routes.  If
                both are present the advisory attribute of  a  route
                object  takes precedence over the advisory attribute
                of the aut-num object.  As with all  advisories  the
                specific semantics are defined by the 'target' AS.

                It  is recommended to limit the use of advisories as
                much as possible and to  use  the  standard  routing
                registry  instead.  It should be considered that the
                use of this attribute requires additional effort  by
                the  maintainers  of  the  objects concerned.  It is
                important to establish their motivation to  register
                and maintain this information properly.
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                ripe-130.txt                                  Page 1
                                              The Advisory Attribute

                                                       David Kessens
                ____________________________________________________

    Definition


                advisory:
                     Advises a  specific  'target'  AS  to  use  the
                     information  that is defined in this attribute.


                     Format:
                          <ASnnnn> <AS specific information>


                          The AS specific  information  is  intended
                          for  use by ASnnnn, the 'target' AS, only.
                          The syntax of the AS specific  information
                          is  defined by ASnnnn and beyond the scope
                          of this document.  It can be  obtained  by
                          contacting  the administrative contacts of
                          ASnnnn which can be found  in  the  corre-
                          sponding aut-num object.

                     Status: optional, multiple lines allowed


    Acknowledgements

                This document is based on a draft by Dale Johnson of
                MERIT.  Adding advisories  to  aut-num  objects  was
                suggested by Christian Panigl of ACOnet.
























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                ripe-130.txt                                  Page 2