NSIS Working Group Tricci So Internet Draft Caspian Networks Expiration Date: Sept 2002 NSIS Scope Recommendations Draft-so-nsis-scope-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract The intent of this draft is to recommend the scope of the work for the NSIS working group so that the team can focus on the key work signaling issues that need to be resolved and to develop the solutions promptly. Conventions Used In This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this document are to be interpreted as described in RFC-2119. So Expires September 2002 [Page 1] Internet Draft draft-so-nsis-scope.txt September 2002 Table Of Contents 1. Motivations....................................................3 2. Modified SIP Network Architecture..............................4 3. Concepts of Bearer Control Signaling vs. Call Control Signaling5 4. Rationales.....................................................5 5. Security Considerations........................................5 6. Recommendation.................................................5 7. IANA Consideration.............................................6 8. References.....................................................6 9. Authors' Addresses.............................................6 So Expires September 2002 [Page 2] Internet Draft draft-so-nsis-scope.txt September 2002 1. Motivations As indicated in the current working group charter, the objective of the NSIS work is to develop a simplified solution to signal QoS requirements for variety types of multimedia services over the Internet. At the moment, the discussions so far seem to look into all aspects of the signaling issues that were encountered in the network. In addition, there is no specific network model that can be referred by the NSIS working group to focus on the signaling requirements discussion at different network levels. Hence, this draft brings forward a network model that was derived from the Session Initiation Protocol (SIP) [RFC 2543] network architecture so that the NSIS working group can use it as the base to identify the scope of the working area and to build the consensus on the requirements as well as the solutions. However, it is not the objective of this draft to propose the following network model as the NSIS signaling reference model. The intents of this draft are: - to identify the two main streams of control signaling in a telecommunication network to support multi-media services - i.e. call control signaling and bearer control signaling. - to recommend the focus on the bearer control signaling by the NSIS WG since it is more related to use of the Internet as the transport medium to support the requested QoS transport characteristic, and leave the call control signaling to other consortium to tackle since it is more related to the network services and policy control. So Expires September 2002 [Page 3] Internet Draft draft-so-nsis-scope.txt September 2002 2. Modified SIP Network Architecture The following describes the network model that is derived from the SIP network architecture that depicts the separation of the call control signaling from the bearer control signaling to support multi-media services. --------------- ----------------- | Application | | Application | | Services |<-SIP-> | Services | | | | | --------------- ----------------- ^ ^ ^ | | | | SIP SIP Call | | Control v v Signaling ------------ ------------ | | Media | | Media | | | Gateway | <-SIP-T-> | Gateway | | |Controller| |Controller| | ------------ ------------ | e.g. ^ ^ ^ ^ e.g | SS7 / | e.g. e.g. | \ MGCP | ---------- | MGCP H.248 | --------- | |PSTN or | | | | IAD | | | PLMN | | | --------- | ---------- | | v *************** v ***************** v ******************** ---------- ---------- - | Media | ---------- | Media | -\ ---/ | Gateway| <- e.g. -> |Gateway | \-----\ / | | RSVP, RTP, | | | | ---------- Diffserv ---------- | | | | <------- Bear Control ------> | | Signaling | \ / \ / ----------------------------------------------- Private and/or Public IP Network where: Diffserv - Differentiated Services IAD - Integrated Access Devices MGCP - Media Gateway Control Protocol PLMN - Public Land Mobile Network PSTN - Public Switching Trunking Network RSVP - Resource ReSerVation Protocol RTP - Realtime Transport Protocol SIP - Session Initiation Protocol SS7 - Signaling System 7 So Expires September 2002 [Page 4] Internet Draft draft-so-nsis-scope.txt September 2002 3. Concepts of Bearer Control Signaling vs. Call Control Signaling The purpose of Bearer Control Signaling is to communicate QoS information to the transport network so that the network can make the necessary arrangements and provide to the requesting application a bearer channel/path with the described transport characteristic. Bearer control signaling does not necessarily traverse the transport network end-to-end uninterrupted, but at certain intermediary nodes is elevated and interpreted. These intermediate nodes need therefore to understand the signaling content and make the necessary actions in response to it. The Call Control signaling could logically be modeled after the manner of an end-to-end application layer protocol specifically tailored for the service at hand. For example, SS7 in PSTN is geared towards providing voice grade services on demand and providing policy control. The span of the call control signaling is likely end-to-end. 4. Rationales Although there is a strong desire from the service providers to consolidate their networks to support multi-media services, their main intent is to converge the transport infrastructure and not the services infrastructure. It is because different types of services require different platforms to manage the services, e.g. SS7 IN services for PSTN, of which those infrastructure takes years to build and to mature. It is extremely economical for the service providers to be able to migrate their multi-media traffic from the multi-services network onto the Internet along with their data traffic. It also open the opportunity for the service providers to offer new services for the emerging new application, e.g. wireless applications and DSL etc. Hence, it is important for the NSIS to develop a generic bearer control signaling mechanism to specify certain transport characteristic to establish the bearer to carry multimedia traffic. 5. Security Considerations N/A 6. Recommendation The intent of this draft is to identify the scope of the NSIS working group on the simplified signaling design to provide QoS support for multimedia services over Internet. So Expires September 2002 [Page 5] Internet Draft draft-so-nsis-scope.txt September 2002 It is important for the NSIS working group to focus on the bearer control aspect of the signaling design so that the Internet can be used to provide high quality transport of the multimedia traffic. 7. IANA Consideration N/A 8. References IETF RFC [Sig-Arch] Menelaos K. Perdikeas, Iakovos S. Venieris, "Signaling and Service Integration between Internet and PSTN" [RFC2543] M. Handley, H.Schulzrinne, E. Schooler, J. Rosenberg, "Session Initiation Protocol", RFC 2543, March 1999. 9. Authors' Addresses Tricci So Caspian Networks 170 Baytech Drive San Jose, CA, USA 95134 Email: tso@caspiannetworks.com So Expires September 2002 [Page 6]