The Model for Net and App Interaction
draft-atarashi-netappmodel-02

Abstract

This document describes the model for application and network interaction in reaction to Application Area Architecture Workshop held on February 11 and 12, 2008. There is not completed mechanism for collaboration between application and network yet even though a solution is required. The model proposed in this document is designed without a layer violation.

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Table of Contents

1.  Introduction
    1.1.  Motivation
    1.2.  Problems
    1.3.  Requirements notation
2.  Adding Building Block
3.  Network and Application Interaction
4.  Security Considerations
5.  Normative References
§  Authors' Addresses

1.  Introduction

This document describes the model for application and network interaction in reaction to Application Area Architecture Workshop held on February 11 and 12, 2008. There is not completed mechanism for collaboration between application and network yet even though a solution is required. The model proposed in this document is designed without a layer violation.

1.1.  Motivation

From the application point of view, application users want to use network resources (ex. bandwidth, response time) and new network functions (ex. QoS, VLAN) flexibly. Applications and services have requirements for network behavior depending on the functions provided by the application. For example, a streaming service requires high bandwidth and low delay network, database transactions need no packet-loss network but don't need high bandwidth.
From the network point of view, it is useful for operation to know the application behavior. If they can know the requirement from application, it may be possible to prepare the responded environment. It was impossible to change the configurations on demand, but NETCONF can be change the configuration flexibly.
Now, it is ready to design the application common architecture, because the components are all together.

1.2.  Problems

One of the reasons that the collaboration is difficult is that we don't share a common architecture and terminology. There is a gap between application requirements and network functions. Application requirements and behavior are defined by service level, but network functions are implemented by routing and low level configurations. When we have a requirement for network behavior, we have to configure routers using CLI (Command Line Interface). It is hard because we have to master router configuration. And it is impossible that configuration changes automatically and frequently.
We need an interface to collaborate between the applications and the network. IMO, the interface is defined not API-like function, but also model-like description. For example,

- Application service model

- Network function model

These kinds of models may be higher level concept than API. As a application user for the NETCONF, the guideline is need to use and combine the application technologies and protocols.

1.3.  Requirements notation

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.).

2.  Adding Building Block

At the Application Area Architecture Workshop, we agreed to add the application *semantic* layer which is really what users are interested in, and this is different even from the application *protocol* layer. For example, "jabber" is in the Semantic Layer, "xmpp" is in the Protocol Layer.

     Layer              examples

+-----------------+    +----------+
| Semantic Layer  |    | jabber   |
+-----------------+    +----------+
| Protocol Layer  |    |  xmpp    |
+-----------------+    +----------+
| Transport Layer |    | TCP/SCTP |
+-----------------+    +----------+
| Internet Layer  |    | IP/IPv6  |
+-----------------+    +----------+
| Datalink Layer  |    | VLAN     |
+-----------------+    +----------+
| Physical Layer  |    | Ethernet |
+-----------------+    +----------+

3.  Network and Application Interaction

In order to implement to interact with application and network, *Management function* is needed outside the layer. Each layer is managed by the management function. The requirements from the Semantic Layer are conveyed to the management function to implement in the other layer. For example, a "closed network" is requested from the application, an VLAN is implemented in the Datalink Layer.

+-----------------+    +------------+
| Semantic Layer  |<-->|            |
+-----------------+    |            |
| Protocol Layer  |<-->|            |
+-----------------+    |            |
| Transport Layer |<-->|            |
+-----------------+    | management |
| Internet Layer  |<-->|            |
+-----------------+    |            |
| Datalink Layer  |<-->|            |
+-----------------+    |            |
| Physical Layer  |<-->|            |
+-----------------+    +------------+

Management function consists of Management Block and APIs to collaborate with each layer and application, network devices. Management block is application or management scenario suite. Applications make requirement to Management Block through the API, Network devices are configured by Management Block through the API.

+-----------------+    +---+-------------+---+
| Semantic Layer  |<-->|   |             |   |
+-----------------+    |   |             |   |requirements
| Protocol Layer  |<-->|   |             |   |<-----> Applications
+-----------------+    |   |             |   |
| Transport Layer |<-->| A |             | A |
+-----------------+    | P |  Management | P |configuration
| Internet Layer  |<-->| I |   Block     | I |<-----> Network Devices
+-----------------+    |   |             |   |
| Datalink Layer  |<-->|   |             |   |
+-----------------+    |   |             |   |
| Physical Layer  |<-->|   |             |   |
+-----------------+    +---+-------------+---+

The Management block consists of scenarios that is a sequence of procedure in order to implement the requirements. The implementation depend on the scenario rely on the network and system environments.

It is important to define "data model" for primitive network functions in corresponding to requirements. These requirements are composed based on the function data model. The network devices are configured when scenario involved the network devices and resources.

4.  Security Considerations

TBD

5. Normative References

Authors' Addresses