Network Working Group R. Hancock
Request for Comments: 4080 Siemens/RMR
Category: Informational G. Karagiannis
University of Twente/Ericsson
J. Loughney
Nokia
S. Van den Bosch
Alcatel
June 2005
Next Steps in Signaling (NSIS): Framework
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 (2005).
Abstract
The Next Steps in Signaling (NSIS) working group is considering
protocols for signaling information about a data flow along its path
in the network. The NSIS suite of protocols is envisioned to support
various signaling applications that need to install and/or manipulate
such state in the network. Based on existing work on signaling
requirements, this document proposes an architectural framework for
these signaling protocols.
This document provides a model for the network entities that take
part in such signaling, and for the relationship between signaling
and the rest of network operation. We decompose the overall
signaling protocol suite into a generic (lower) layer, with separate
upper layers for each specific signaling application.
Table of Contents
1. Introduction ....................................................3
1.1. Definition of the Signaling Problem ........................3
1.2. Scope and Structure of the NSIS Framework ..................3
2. Terminology .....................................................4
3. Overview of Signaling Scenarios and Protocol Structure ..........6
3.1. Fundamental Signaling Concepts .............................6
3.1.1. Simple Network and Signaling Topology ...............6
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RFC 4080 NSIS Framework June 2005
3.1.2. Path-Coupled and Path-Decoupled Signaling ...........7
3.1.3. Signaling to Hosts, Networks, and Proxies ...........8
3.1.4. Signaling Messages and Network Control State .......10
3.1.5. Data Flows and Sessions ............................10
3.2. Layer Model for the Protocol Suite ........................11
3.2.1. Layer Model Overview ...............................11
3.2.2. Layer Split Concept ................................12
3.2.3. Bypassing Intermediate Nodes .......................13
3.2.4. Core NSIS Transport Layer Functionality ............15
3.2.5. State Management Functionality .....................16
3.2.6. Path-Decoupled Operation ...........................17
3.3. Signaling Application Properties ..........................18
3.3.1. Sender/Receiver Orientation ........................18
3.3.2. Uni- and Bi-Directional Operation ..................19
3.3.3. Heterogeneous Operation ............................19
3.3.4. Aggregation ........................................20
3.3.5. Peer-Peer and End-End Relationships ................21
3.3.6. Acknowledgements and Notifications .................21
3.3.7. Security and Other AAA Issues ......................22
4. The NSIS Transport Layer Protocol ..............................23
4.1. Internal Protocol Components ..............................23
4.2. Addressing ................................................24
4.3. Classical Transport Functions .............................24
4.4. Lower Layer Interfaces ....................................26
4.5. Upper Layer Services ......................................27
4.6. Identity Elements .........................................28
4.6.1. Flow Identification ................................28
4.6.2. Session Identification .............................28
4.6.3. Signaling Application Identification ...............29
4.7. Security Properties .......................................30
5. Interactions with Other Protocols ..............................30
5.1. IP Routing Interactions ...................................30
5.1.1. Load Sharing and Policy-Based Forwarding ...........31
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