Application Configuration Access Protocol

1
Application Configuration Access Protocol

• Praveen S Thangavelu
• Nov-12-2003
• Advisor Dr Chung-E-Wang
• Department of Computer Science, CSUS

2
Motivation and Agenda

• Opportunity to study, design and implement a real
  life internet protocol
• Solution to client mobility
• Understanding RFC specifications
• Agenda
• Overview
• Protocol Framework
• ACAP Commands
• Design Issues Methodology, scope clients
• Major functionality
• Problems
• Results and Future enhancements

3
Overview

• Companion protocol to IMAP
• IMAP vs. ACAP
• History IMSP and ACAP
• Directory Service??
• Application of ACAP and Example
• ACAP Usage for Mobile User
• Example Clients
• EUDORA ACAP enabled

4
Data Model and Design Goals

• ACAP Data Model
• Datasets, entries and attributes
• Tree of entries
• Rules with which clients access datasets are
  specified in dataset classes
• Pre-defined attributes
• Design Goals
• Access Configuration/Preferences remotely
• Emphasis on client simplicity
• Easily manageable Dataset Inheritance
• Clients with intermittent access- slow clients
  modtime attribute
• Operated well with Large clients

5
Protocol Framework

• Link Level
• Assumes reliable data stream (TCP/Port 674)
• Client Server connection
• Text based line oriented protocol
• Commands and responses
• Client command
• Server data
• Server completion results
• Tagged response command continuation request
• Operational Considerations
• Data transferred comply with underlying transport
  window size
• Multiple commands

6
Server States

• Connection
• ACAP greeting
• Rejected Connection
• Bye Greeting
• Successful Authenticate
• Logout
• Logout command
• Server shutdown
• Connection closed

7
Protocol Elements

• Datasets
• Entries, attributes
• Response code
• OK, BAD, NO
• Access Control Lists
• Namespaces
• Functionality
• Communication
• Dataset definition
• Parsing system

8
Implementation Issues

• Communication Subsystem
• Multiple clients
• In memory representation of data
• ACAP Command Parsing
• Some Server Response codes Modified
• Datasets
• CREATE, READ, STORE
• Compatibility with real time mail clients
• Other mail clients pine

9
Some Sample Results

• Client ltestablishes connectiongt
• Server ACAP (IMPLEMENTATION "Plugged In ACAP
  Server v1.03") (CONTEXTLIMIT "150") (SASL
  "CRAM-MD5" "KERBEROS_V4")
• Client GH45 STORE ("/addressbook/user/praveen"
• "Contact.Name" "Praveen" "Contact.Email"
  
• "praveen_at_ecs.csus.com")
• Server GH45 OK "STORE completed"
• Client GH46 LOGOUT
• Server BYE "See ya later"
• Server GH46 OK "LOGOUT completed
• Planning to store configuration Information for
  Pine or ELM

10
Future Enhancements

• Server Replication/ Mirroring
• Extending per user data to group of users
• Scope Extension
• Complex Search Queries
• Authorization using ACL
• Include contexts per session
• Extension to Web based clients like squirrel mail