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Description: Request For Comments

You can download source copies of the file as follows:

draft-bidulock-sigtran-isua-04.txt in text format. in ps format.
draft-bidulock-sigtran-isua-04.pdf in pdf format.

Listed below is the contents of file draft-bidulock-sigtran-isua-04.txt.

Network Working Group                                     Brian Bidulock
INTERNET-DRAFT                                       OpenSS7 Corporation
Intended status: PROPOSED STANDARD                      February 3, 2007

Expires in August 2007

                     SS7 ISUP-User Adaptation Layer

Status of this Memo

    By submitting this Internet-Draft, each author represents that any
  applicable patent or other IPR claims of which he or she is aware have
  been or will be disclosed, and any of which he or she becomes aware
  will be disclosed, in accordance with Section 6 of BCP 79.

    Internet-Drafts are working documents of the Internet Engineering
  Task Force (IETF), its areas, and its working groups.  Note that other
  groups may also distribute working documents as Internet-Drafts.

    Internet-Drafts are draft documents valid for a maximum of six
  months and may be updated, replaced, or obsoleted by other documents
  at any time.  It is inappropriate to use Internet-Drafts as reference
  material or to cite them other than as "work in progress".

    The list of current Internet-Drafts can be accessed at

    The list of Internet-Draft Shadow Directories can be accessed at

    This Internet-Draft will expire in August 2007.


    Copyright (C) The IETF Trust (2007).


    This document defines a protocol for the transport of any SS7 ISUP-
  User signalling (e.g, Call Control) over IP using the Stream Control
  Transport Protocol [SCTP].  The protocol should be modular and
  symmetric, to allow it to work in diverse architectures, such as a
  Signalling Gateway and IP Signalling End-point architecture.  Protocol
  elements are added to allow seamless operation between peers in the
  SS7 and IP domains.

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Internet Draft       SS7 ISUP-User Adaptation Layer     February 3, 2007


    A complete table of contents, list of illustrations, list of tables
  and document change history appear at the end of this document.

1.  Introduction

    This draft defines a protocol for the transport of SS7 ISUP [Q.761],
  [T1.113] Users (i.e, Call Control) signalling messages over IP using
  the Stream Control Transmission Protocol (SCTP) [SCTP].  This protocol
  would be used between a Signalling Gateway (SG) and Signalling End-
  point located in an IP network.  Additionally, the protocol can be
  used to transport SS7 ISUP users between two signalling end-points
  located within an IP network.

1.1.  Scope

    There is on-going integration of SCN networks and IP networks.
  Network service providers are designing all IP architectures that
  include support for SS7 signalling protocols.  IP provides an
  effective way to transport user data and for operators to expand their
  networks and build new services.  In these networks, there is a need
  for interworking between the SS7 and IP domains [RFC2719].

    This document details the delivery of Call Control messages over IP
  between two signalling end-points.  Consideration is given for the
  transport from an SS7 Signalling Gateway (SG) to an IP signalling node
  (such as an IP-resident Database) as described in the Framework
  Architecture for Signalling Transport [RFC2719] This protocol can also
  support transport of Call Control messages between two end-points
  wholly contained within and IP network.

  The delivery mechanism addresses the following criteria:

   + Support for transfer of ISUP messages (Call Control)
   + Support for the seamless operation of Call Control protocol peers.
   + Support for the management of SCTP transport associations between
     an SG and one ore more IP-based signalling nodes.
   + Support for distributed IP-based signalling nodes.
   + Support for the asynchronous reporting of status changes to

1.2.  Abbreviations and Terminology

1.2.1.  Abbreviations

      ANSI -- American National Standards Institute.
      API  -- Application Programming Interface.
      AS   -- Application Server.
      ASP  -- Application Server Process.

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Internet Draft       SS7 ISUP-User Adaptation Layer     February 3, 2007

      BLA  -- Blocking Acknowledgement.
      BLO  -- Blocking Request.
      CA   -- Certificate Authority.
      CC   -- Call Control.
      CCR  -- Continuity Check Request.
      CGBA -- Circuit Group Blocking Acknowledgement.
      CGB  -- Circuit Group Blocking Request.
      CGUA -- Circuit Group Unblocking Acknowledgement.
      CGU  -- Circuit Group Unblocking Request.
      CMF  -- Circuit Mapping Function.
      COT  -- Continuity Test.
      CP   -- Call Processing.
      CQM  -- Circuit Group Query Request.
      CQR  -- Circuit Group Query Response.
      CTP  -- Common Transport Protocol.
      ETSI -- European Telecommunication Standards Institute.
      GRS  -- Group Reset.
      HLR  -- Home Location Register.
      IANA -- Internet Assigned Numbers Authority.
      IETF -- Internet Engineering Task Force.
      IP   -- Internet Protocol.
      IPSP -- IP Signalling Point.
      ISDN -- Integrated Services Digital Network.
      ISO  -- International Standards Organization.
      ISUA -- SS7 ISUP-User Adaptation Layer.
      ISUP -- ISDN User Part.
      ITU  -- International Telecommunications Union.
      L1   -- Layer 1.
      LM   -- Layer Management.
      LPA  -- Loop Back Acknowledgement.
      MGC  -- Media Gateway Controller.
      MTP2 -- MTP Level 2.
      MTP3 -- MTP Level 3.
      MTP  -- Message Transfer Part.
      NA   -- Network Appearance.
      NIF  -- Network Interworking Function.
      PSTN -- Public Switched Telephone Network.
      RC   -- Routing Context.
      RFC  -- Request For Comments.
      RK   -- Routing Key.
      RKM  -- Routing Key Management.
      RSC  -- Reset Circuit.
      SCN  -- Switch Circuit Network.
      SCP  -- Service Control Point.
      SCTP -- Stream Control Transmission Protocol.
      SG   -- Signalling Gateway.
      SGP  -- Signalling Gateway Process.
      SS7  -- Signalling System No. 7.
      SSP  -- Service Switching Point.
      STP  -- Signalling Transfer Point.
      TLI  -- Transport Layer Interface.
      TLS  -- Transport Layer Security.

B. Bidulock                    Version 0.4                        Page 3

Internet Draft       SS7 ISUP-User Adaptation Layer     February 3, 2007

      TLV  -- Tag-Length-Value.
      UBA  -- Unblocking Acknowledgement.
      UBL  -- Unblocking Request.
      VPN  -- Virtual Private Network.
      XTI  -- X/Open Transport Interface.

1.2.2.  Terminology

  Application Server (AS) - a logical entity serving a specific Routing
      Key.  An example of an Application Server is a virtual database
      element handling all HLR or SCP transactions for a particular SS7
      Signalling Point.  The AS contains a set of one or more unique
      Application Server Processes, of which one or more is normally
      actively processing traffic.  There is a one-to-one relationship
      between an Application Server and a Routing Key.

  Application Server Process (ASP) - a process instance of an
      Application Server.  An Application Server Process serves as an
      active, backup, load-share or broadcast process of an Application
      Server (e.g, part of a distributed signalling node or database
      element).  Examples of ASPs are MGCs, IP SCPs, or IP HLRs.  An ASP
      contains an SCTP end-point and may be configured to process
      traffic within more that one Application Server.

  Association - refers to an SCTP association [SCTP].  The association
      provides the transport for the delivery of ISUP protocol data
      units and ISUA layer peer messages.

  Call Control - The layer above the ISDN User Part in the SS7 protocol
      stack that exchanges primitives with the ISUP provider.  Call
      Control has two major functional blocks: Call Processing and
      Circuit Supervision.  Unlike other