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.
Copyright Notice
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.
Table of Contents
1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Terms and Definitions . . . . . . . . . . . . . . . . . . 2
2. IEPREP Topologies. . . . . . . . . . . . . . . . . . . . . . 2
2.1 Topology "IP Bridging" . . . . . . . . . . . . . . . . . 3
2.2 Topology "IP at the Start". . . . . . . . . . . . . . . . 3
2.3 Topology "IP at the End". . . . . . . . . . . . . . . . . 4
2.4 Topology "End-to-End IP". . . . . . . . . . . . . . . . . 4
3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Author's Address. . . . . . . . . . . . . . . . . . . . . . . 5
8. Full Copyright Statement. . . . . . . . . . . . . . . . . . . 6
Polk Informational [Page 1]RFC 3523 IEPREP April 2003
1. Introduction
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).
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 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. 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"
Polk Informational [Page 2]RFC 3523 IEPREP April 2003
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 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"
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"
Polk Informational [Page 3]RFC 3523 IEPREP April 2003
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"
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"
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.
Polk Informational [Page 4]RFC 3523 IEPREP April 2003
3. Security Considerations
This document merely suggests a common naming convention within
IEPREP WG discussions, therefore there are no special security
considerations.
4. IANA Considerations
There are no IANA considerations within this document.
5. Acknowledgements
To Scott Bradner, Kimberly King and Mike Pierce for their comments
and suggestions.
6. References
There are no references at the present time.
7. Author's Address
James M. Polk
Cisco Systems
2200 East President George Bush Turnpike
Richardson, Texas 75082 USA
EMail: jmpolk@cisco.com
Polk Informational [Page 5]
RFC 3523 IEPREP April 2003
8. Full Copyright Statement
Copyright (C) The Internet Society (2003). 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
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kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
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English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Polk Informational [Page 6]
