OpenCAPWAP : An open source CAPWAP implementation for the management and configuration of

WiFi hot-spots

김준호2015.08.10

Mobile Convergence LAB,Department of Computer Engineering,

Kyung Hee University.

1. About paper & terms

2. CAPWAP protocol

3. CAPWAP Implementation

4. Experiment

5. Q&A

Contents

Internet Engineering Task Force

Computer Networks- The International Journal of Computer and Telecommunications Networking

Computer Networks 53 (2009) 217-230

M. Bernaschi, F. Cacace, G.Iannello, M. Vellucci, L. Vollero*

Rome, Italy

About paper & terms

1. CAPWAP – Control And Provisioning of Wireless Access Points

2. AC – Access Controller

3. WTP – Wireless Termination Points

4. STA – STAtion

=> A device that contains an interface to a wireless medium

About paper & terms

1. The Number of AP up

2. Hard to Management, configuration and control

3. Want to Simplifying functionalities and Centralizing functions

CAPWAP protocol - Background

1. Centralize authentication and policy enforcement functions for a

wireless network.

2. Move processing away from the WTPs, leaving there only time crit-

ical functions.

3. Provide a generic encapsulation and transport mechanism.

IETF – CAPWAP WG(Working Group)’s goal

Enabling an AC to manage and control a collection of

possibly heterogeneous WTPs.

CAPWAP protocol

1. Using UDP, DTLS(Datagram Transport Layer Security)

2. Using request/response paradigm(supplement UDP)

3. CAPWPA data messages & CAPWAP control messages

4. Quality of Service message

CAPWAP protocol

CAPWAP protocol - QoS

CAPWAP implementation - FSM

CAPWAP implementation - FSM

CAPWAP implementation - FSM

CAPWAP implementation - FSM

CAPWAP implementation - FSM

CAPWAP implementation - FSM

CAPWAP implementation - AC

Modularity & Efficiency

CAPWAP implementation - WTP

Always 3 threads

Experiment

1. Delay check

2. Frequency Planning

3. Load Balancing

4. WMM Parameters Adaptation

Experiment – Testbed

1. One AC & Five WTPs

2. HP tc4200 tablet PC1. Pentium M 1.73GHz processor

2. Linux Ubuntu OS, kernel version 2.6.15-26-386

3. WTP1. Wireless PCI NIC, a NETGEAR GW511T using an Atheros chip, capable of work-

ing in master mode

4. NIC1. Support subset of the IEEE 802.11e

Experiment – Delay check

Average delay

Flood case

Experiment – Frequency Planning

RANDOM – Each

WTP uses a channel

randomly chosen

CLOSEST – Con-

sider the activities of

neighbors WTPs,

use as the channel

orthogonal to those

of the two closest

WTPs

Experiment – Load Balancing

Nmax – Maximum number of STAs associated to a single WTP

FIXED – Fixed power

level

LOAD BALANCING

– WTP can enable

three possible power

level.

Experiment – WMM Parameters Adaptation

delay -> Down-link delay

Two down-link TCP

flows & One up-link

UDP flows

50s -> Start saturated

BE traffic

Q&A

Thank you so much