Browse Prior Art Database

Criteria for Evaluating Network Access Server Protocols (RFC3169) Disclosure Number: IPCOM000005374D
Original Publication Date: 2001-Sep-01
Included in the Prior Art Database: 2001-Sep-17
Document File: 18 page(s) / 35K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. Beadles: AUTHOR [+1]


This document defines requirements for protocols used by Network Access Servers (NAS).

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 9% of the total text.

Network Working Group M. Beadles Request for Comments: 3169 SmartPipes, Inc. Category: Informational D. Mitton Nortel Networks

September 2001

Criteria for Evaluating Network Access Server Protocols

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 (2001). All Rights Reserved.


This document defines requirements for protocols used by Network Access Servers (NAS).

1. Requirements language

In this document, the key words "MAY", "MUST, "MUST NOT", "optional", "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as described in [KEYWORDS].

2. Introduction

This document defines requirements for protocols used by Network Access Servers (NAS). Protocols used by NAS's may be divided into four spaces: Access protocols, Network protocols, AAA protocols, and Device Management protocols. The primary focus of this document is on AAA protocols.

The reference model of a NAS used by this document, and the analysis of the functions of a NAS which led to the development of these requirements, may be found in [NAS-MODEL].

3. Access Protocol Requirements

There are three basic types of access protocols used by NAS's. First are the traditional telephony-based access protocols, which interface to the NAS via a modem or terminal adapter or similar device. These protocols typically support asynchronous or synchronous PPP [PPP]

Beadles Mitton Informational [Page 1]

RFC 3169 Criteria for Evaluating NAS Protocols September 2001

carried over a telephony protocol. Second are broadband pseudo- telephony access protocols, which are carried over xDSL or cable modems, for example. These protocols typically support an encapsulation method such as PPP over Ethernet [PPPOE]. Finally are the virtual access protocols used by NAS's that terminate tunnels. One example of this type of protocol is L2TP [L2TP].

It is a central assumption of the NAS model used here that a NAS accepts multiple point-to-point links via one of the above access protocols. Therefore, at a minimum, any NAS access protocol MUST be able to carry PPP. The exception to this requirement is for NAS's that support legacy text login methods such as telnet [TELNET], rlogin, or LAT. Only these access protocols are exempt from the requirement to support PPP.

4. Network Protocol Requirements

The network protocols supported by a NAS depend entirely on the kind of network to which a NAS is providing access. This document does not impose any additional requirements on network protocols beyond the protocol specifications themselves. For example, if a NAS that serves a routed network includes internet routing functionality, then that NAS must adhere to [ROUTING-REQUIREMENTS], ...