Internet Engineering Task Force James M. Polk Internet Draft Cisco Systems Expiration: April 10th, 2003 File: draft-polk-ieprep-scenarios-01.txt IEPREP Topology Scenarios October 10th, 2002 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 This memo conveys simplistically the likely topological scenarios that may be encountered in reference to IEPREP phone calls. These scenarios should be used to focus the IEPREP Working Group during discussions and when writing requirements, gap analysis and other solutions documents. Polk IEPREP Topology Scenarios Page 1 Internet Draft draft-polk-ieprep-scenarios-01.txt Oct 10th, 2002 Table of Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Changes from -00 version . . . . . . . . . . . . . . . . . . . . . 2 1.3 Terms and Definitions . . . . . . . . . . . . . . . . . . . . . . 3 2.0 IEPREP Topologies . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1 Topology A "IP Bridging" . . . . . . . . . . . . . . . . . . . . . 3 2.2 Topology B "IP at the Start" . . . . . . . . . . . . . . . . . . . 4 2.3 Topology C "IP at the End" . . . . . . . . . . . . . . . . . . . . 4 2.4 Topology D "End-to-End IP" . . . . . . . . . . . . . . . . . . . . 5 3.0 Security Considerations . . . . . . . . . . . . . . . . . . . . . . 5 4.0 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . . . 5 5.0 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.0 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.0 Authors Information . . . . . . . . . . . . . . . . . . . . . . . . 5 1.0 Introduction This memo conveys simplistically the likely topological scenarios that may be encountered in reference to IEPREP phone calls. These scenarios should be used to focus the IEPREP Working Group during discussions and when writing requirements, gap analysis and other solutions documents. There has been much confusion on the IEPREP list as well as within each meeting about the topologies IEPREP is considering. Hopefully this document will give each reader and author a reference set of named architectures. This memo attempts to be agnostic with regard to IP signaling or control protocols (SIP, MEGACO, etc), as well as any underlying QOS mechanisms (Diffserv, RSVP, NSIS, etc). 1.1 Motivation Simply put, to get everyone referencing the same (named) topologies in order to have useful and less confusing dialog to further this working group's efforts. 1.2 Changes from -00 version This version greatly reduces the text of the overall document by removing all discussion of requirements and authentication & authorization. This is not a requirements document (therefore shouldn't state any), and the A&A text/discussion for each of the topologies, though necessary within the Polk IEPREP Topology Scenarios Page 2 Internet Draft draft-polk-ieprep-scenarios-01.txt Oct 10th, 2002 WG, has been moved to another "ieprep-topology-implications" document. 1.3 Terms and Definitions The following acronyms need to be exploded for clarity: CSN = Circuit Switched Network GW = Gateway (CSN to IP, or IP to CSN) 2.0 IEPREP Topologies There are 4 often mentioned, but very little documented topologies discussed within this WG's efforts so far. The following subsections name and describe each of the topologies. The 4 topologies are (quickly): Topology "IP Bridging" Topology "IP at the Start" Topology "IP at the End" Topology "End-to-End IP" 2.1 Topology "IP Bridging" This topology is sometimes known as "IP in the Middle" of two CSNs. In this topology, a CSN phone of any type initiates (dials) a call (session) to another CSN phone with an IP core between the two CSNs. This topology should simplistically look like this: Circuit Internet Circuit Switched IP or IP Switched Network Ingress IP Segment Egress Network -----------+ +--------------+ +----------- | +----+ | IP | +----+ | CSN | | | | | | | | CSN Phone ------->| GW |----------------------->| GW |-------->Phone | | | | | | | | | +----+ | | +----+ | -----------+ +--------------+ +----------- Figure 1. Topology "IP Bridging" Polk IEPREP Topology Scenarios Page 3 Internet Draft draft-polk-ieprep-scenarios-01.txt Oct 10th, 2002 2.2 Topology "IP at the Start" This topology has the initiating party placing (dialing) the call from an IP Phone (PDA or computer), and the called party residing in the CSN. Internet Circuit or CSN Switched IP Segment Ingress Network -------------------+ +--------------- | +----+ | IP | | | | CSN Phone ------------------>| GW |--------> Phone | | | | | +----+ | -------------------+ +--------------- Figure 2. Topology "IP at the Start" One key aspect of this topology is where the intelligence is for any prioritization of call/session handling. Initially, it cannot be assumed that the CSN Ingress GW is ETS or priority-aware. 2.3 Topology "IP at the End" This topology has the calling party placing the call from a CSN phone, and the called party being in an IP network. Circuit Internet Switched CSN or Network Egress IP Segment -------------------+ +--------------- | +----+ | CSN | | | | IP Phone ------------------>| GW |--------> Phone | | | | | +----+ | -------------------+ +--------------- Figure 3. Topology "IP at the End" Polk IEPREP Topology Scenarios Page 4 Internet Draft draft-polk-ieprep-scenarios-01.txt Oct 10th, 2002 2.4 Topology "End-to-End IP" This topology has no circuit switched sections in the call path. Internet or IP Network +-----------------------------------------+ | | +---------+ +-----------+ | | | IP IP | | Phone --------------------------------------------> Phone | | | +---------+ +-----------+ | | +-----------------------------------------+ Figure 4. Topology "End to End IP" 3.0 Security Considerations This document merely suggests a common naming convention within IEPREP WG discussions, therefore there are no special security considerations. 4.0 IANA Considerations There are no IANA considerations within this document 5.0 Acknowledgements To Scott Bradner and to Kimberly King for their comments and suggestions 6.0 References none at this moment 7.0 Authors Information James M. Polk Cisco Systems 2200 East President George Bush Turnpike Richardson, Texas 75082 USA jmpolk@cisco.com Polk IEPREP Topology Scenarios Page 5 Internet Draft draft-polk-ieprep-scenarios-01.txt Oct 10th, 2002 "Copyright (C) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. 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The Expiration date for this Internet Draft is: April 10th, 2003 Polk IEPREP Topology Scenarios Page 6