Network Working Group J. Polk Request for Comments: 3523 Cisco Systems Category: Informational April 2003
Internet Emergency Preparedness (IEPREP) Telephony Topology Terminology
Status of this Memo
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
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Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This document defines the topology naming conventions that are to be used in reference to Internet Emergency Preparedness (IEPREP) phone calls. These naming conventions should be used to focus the IEPREP Working Group during discussions and when writing requirements, gap analysis and other solutions documents.
This document defines the topology naming conventions that are to be used in reference to IEPREP phone calls. These naming conventions should be used to focus the IEPREP Working Group (WG) 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 Quality of Service (QOS) mechanisms (Diffserv, RSVP, NSIS, etc).
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.
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.
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 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 | | | | | | | | | +----+ | | +----+ | -----------+ +--------------+ +-----------
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"
Although shown as one large IP cloud here, the Internet is composed of a series of loosely connected IP domains. An End-to-End IP call will likely traverse a number of these domains and/or multiple network providers, which may impact the call.
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