Network Architecture for

Virtual Network Appliances

Tadashi Okoshi

89831191, slash@mag.keio.ac.jp

Hideyuki Tokuda LaboratoryDigital Media Infrastructure Software Project

Research Abstract

Application Layer Network (ALN) Focuses on the home appliances network Approach in the application layer of network

Provides… Communication transparency

through heterogeneous network architectures

Communication continuity across relocation of hosts and applications

Application

App(a)App(a) App(b)App(b)

HeterogeneousHosts and Networks

App(b)App(b)Relocation

Heterogeneous Communication

MobileCommunication

Contents 1.Background

Network Appliance VNA

2.Network Architecture for VNA Characteristics & Issues

3.ALN Architecture Application Layer Approach Architecture Design Detail of Mobile Communication

4.Evaluation 5.Conclusion and Future Work

1.Research Background:Network Appliance

Network Appliance Appliance with the functionalities of

collaborative behavior through its network connectivity.

Factors Small-size and powerful processor Wired/wireless network technologies

Network Appliances

Cellular Phonewith Internet Connectivity

Digital Camerawith Network Connectivity

Digital Video CameraWith A/V Network Connection

Microwavewith Network Connectivity

© Cannon

© NTT DoCoMo

© Sony © Sharp

Piconet(Embedded Wireless)

IrDA(Infrared)

Ethernet(LAN)

USB(PC Devices)

IEEE1394(A/V Devices)

WaveLAN(Wireless LAN)

Example Host with Multiple Network Interfaces

Ethernet(LAN)

USB(PC Devices)

IrDA(Infrared)

IEEE1394(A/V Devices)

© Sony

Combinational use ofthe numerous appliances

on the network

Network

1.Research Background:Virtual Network Appliance (VNA)

Achieves combinational use based on functional components of the appliances

Combination is abstracted as Virtual Network Appliance (VNA)

Ex. “Virtual VCR” VNA Audio/Video data play-back

Room(A) Room(B)

Room(C)

“Virutal VCR” VNA

Data ReaderData Reader

Video PlayerVideo Player

Audio PlayerAudio Player

2.Research Focus:Network for VNA Architecture

(1) Characteristics Heterogeneity of connecting hosts Heterogeneity of network

architectures Mobility

(2) Issues

22 ℃

36 ℃

Digital A/V Network (e.g. IEEE1394)

Embedded Wireless Network (e.g. Piconet)

LAN (e.g. Ethernet)

Sensor Network(e.g. RS-232C)

Bluetooth

IrDA

IEEE1394

USB, IrDA, IEEE1394, Ethernet

Mobile Hosts and Equipments

Network (A)

Network (B)

MobileHost(A)

Host(B)

Host(A)

B

Relocation(User)

A

App(b)

App(a)

BB

App(c)

A

Relocation(Host)

MobileHost(A)

A

App(b)

App(a)

Relocation(Application)

App(a)

2.Research Focus:Network Architecture for VNA (1) Characteristics (2) Issues

Applications’… Communication transparency

through the coexisting multiple network architectures

Communication continuity across the relocation of hosts and applications

3.Proposed System:Application Layer Network (ALN) Network architecture built on the

transport layer Goal

Communication Transparency Communication Continuity

Functionalities Heterogeneous Communication Mobile Communication

Exploits “Application Layer Approach”

SessionLayer

ApplicationLayer

PresentationLayer

ApplicationLayer

Physical

Datalink

Network

Transport

Layer 5

Layer 6

Layer 7

ISO OSI Reference Model The Internet (TCP/IP) Model

TCP/UDP/IP

EthernetIEEE802.3

WirelessIEEE802.11

IEEE1394 IrDA

Etc…

Application Layer Network (ALN)

Application

Layers

Features of Application Layer Approach

Communication transparency Applicability for diverse Layer1-4 networks

by Zero-Modification for Layer1-4 protocols

⇒ Characteristic: Heterogeneity of networks Simplified and Minimized Mechanisms

by using functionalities of Layer1-4 protocols

⇒ Characteristic: Heterogeneity of hosts (Especially for those with limited capability i.e., PDAs, Home appliances)

Features of Application Layer Approach

Communication continuity Achieve {Virtual Circuit, Datagram}

communication continuityby using Layer-4 transport protocols

Friendliness with applicationapplicable for mobile applications and agents ⇒ characteristics: Mobility

Applicability for diverse Layer1-4 networksby Zero-Modification for Layer1-4 protocols(Continuity across the heterogeneous networks)

⇒ characteristics: Heterogeneity of networks

Features of Application Layer Approach

High Portability Zero modification for Layer1-4

protocols Implementation with code

segmentation Platform Independent Subsystem Platform dependent Subsystem

Architecture & Functionalities

2 Layers in ALN HCL

- Communication Transparency- Provides comm. transport which is independent of layer1-4.

MCL- Communication Continuity- Provides comm. interface which is continuous across the relocation of communication endpoint.

ALNALN

HeterogeneousCommunication Layer (HCL)

Layer1 ～ 4

Applications

…Heterogeneous Network Architectures

Network(a)

Mobile Communication Layer (MCL)

Network(b)

Network(c)

…

Ap

plica

tion

La

yer

Architecture and Functionalities

2 Layers in ALN HCL

- Communication Transparency- Provides comm. transport which is independent of layer1-4.- Application can communicate without being aware of the heterogeneous layer1- 4 networks.

MCL

ALNALN

HeterogeneousCommunication Layer (HCL)

Layer1 ～ 4

Applications

…Heterogeneous Network Architectures

Network(a)

Mobile Communication Layer (MCL)

Network(b)

Network(c)

…

Ap

plica

tion

La

yer

Architecture and Functionalities

ALNALN

HeterogeneousCommunication Layer (HCL)

Layer1 ～ 4

Applications

…Heterogeneous Network Architectures

Network(a)

Mobile Communication Layer (MCL)

Network(b)

Network(c)

…

Ap

plica

tion

La

yer

2 Layers in ALN HCL MCL

- Communication Continuity- Provides comm. transport which is continuous across the relocation of communication endpoint.- Application can communicate continuously after the relocation.

ALN-Heterogeneous Communication Layer (HCL)

IrLAP

IrLMP

IrTTP

IrDA TCP/IP IEEE1394

Application

ALN-HCL

IrLAP

IrLMP

IrTTP

Ethernet

IP

TCP/UDP

Ethernet

IP

TCP/UDP

Datalink

1394

1394 Trans

Datalink

1394

1394 Trans

Host(1) Host(2) Host(3) Host(4)

L4

L3

L2

L1

L5

PalmPalm

Communication between Applications

Communication Endpoint Identifier

Routing/Connection Redirecting

Interface for Applications

Host Addressing

HCL Design (1) Host Addressing

ALN-HostAddress for each host Allocated by hand Ex. “VAIO-Server-Dad”

Communication Endpoint ID (ALN-HostAddress, ALN-PortName) Port guarantees uniqueness inside a host Ex. (“VAIO-Server-Dad”, “VODServer”)

Routing Interface to Applications

HCL Design (2)

Routing Reactive routing protocols for Ad-hoc

Network Interface to Applications

Virtual Circuit Datagram

ALN-Mobile Communication Layer (MCL)

IrDA TCP/IP IEEE1394

ALN-HCL

Host(1) Host(2) Host(3) Host(4)

L5

L4

L1

PalmPalm

Communication between Applications

ALN-MCL

…

BBAA A’A’

Relocation

Connection Switching

Guarantee of Byte Stream Consistency

Interface for Applications

MCL Design & Mechanisms Connection Switch

Dynamic Socket Switching (DSS) Byte Stream Consistency Support

For Virtual Circuit Communication Retainment Application Layer Window (ALW) Retransmit of the data in ALW after the relocation

Interface for Applications MobileSocket interface Applications can use one persistent

MobileSocket connection even after the relocation of communication endpoint

EstablishedEstablishedImplicitlySuspendedImplicitly

SuspendedExplicitly

SuspendedExplicitly

Suspended

ClosedClosedConnected to Server (DSS-EstablishmentPhase(Client) )

Connected from Client (DSS-EstablishmentPhase(Server) )

Lost IP address

Get IP address (Reconnect to CH, DSS-

ImplicitResume Phase)

Reconnected from MH(DSS-ImplicitResume Phase)

Called suspend()suspend() (send SUSPEND_SIGNAL, DSS-ExplicitSuspend Phase)

Called resume()resume() (Reconnect to CH, DSS- ExplicitResume Phase)

reconnected from MH(DSS-ExplicitResume Phase)

received SUSPEND_SIGNAL (DSS-ExplicitSuspend Phase)

DataSocket broken-pipe

Reconnected from MH(DSS-ImplicitResume Phase)

Called close()close()(close connection)

Called close()close()or timedout

(close connection)

Called close()close()(close connection)

Called close()close()(close connection)

Called close()close()or timedout

(close connection)

Normal Transitions for CHNormal Transitions for MH

Normal Transitions for ClientNormal Transitions for Server

Transition trigger(action)

START POINTSTART POINT

StateState

ClientClient ServerServerDataDataSocketSocket

ControlControlSocketSocket

connectconnect accept()accept()

ControlSocket port, AuthenticationSEED1

accept()accept()connect()

ACK

AuthenticationSEED1

DS

S-E

sta

blis

hm

ent

Ph

as

e

RedirectionRedirectionServSocketServSocket

RedirectionServer port, Next_SEED

Data

ALW ACK

DataDataSocketSocket

ControlControlSocketSocket

RedirectionRedirectionServSocketServSocket

CreateCreateSocketSocket

CreateCreateSocketSocket

CreateCreateSocketSocket

CreateCreateSocketSocket

ControlSocket

connect() accept()

ACK, ControlSocket port, AuthenticationSEED3

accept()connect()

ACK

AuthenticationSEED3

DS

S-I

mp

licit

Re

su

me

Ph

as

eRedirectionServSocket → DataSocket

RedirectionServer port, Next_SEED

DataSocket

ControlSocket

RedirectionServSocket

NewRedirectionServSocket

Next_SEED

unlock

READ_COUNTER

unACKed Data retransmit

～ disconnected ～lose IP

get IP

CreateSocket

CreateSocket

CreateSocket

CreateSocket

ControlSocket

connect() accept()

ACK, ControlSocket port, AuthenticationSEED3

accept()connect()

ACK

AuthenticationSEED3

DS

S-I

mp

licit

Re

su

me

Ph

as

eRedirectionServSocket → DataSocket

RedirectionServer port, Next_SEED

DataSocket

ControlSocket

RedirectionServSocket

Mobile HostMobile Host Correspondent HostCorrespondent HostNewRedirectionServSocket

Next_SEED

unlockunlock

READ_COUNTER

unACKed Data retransmit

～ disconnected ～lose IPlose IP

get IPget IP

CreateSocket

CreateSocket

CreateSocket

CreateSocket

Prototype Implementation ALN-HCL

Platform: Linux-2.2.13 Language: C Network: TCP/IP, IrDA, Serial+Mux Server & Library

ALN-MCL Language: Java1.1 Jp.ac.keio.sfc.ht.mobilesocket Class

Library MobileSocket (TCP Mobile Socket) MobileDatagramSocket (UDP Mobile Socket)

Client SocketServerSocket

L1-4 Interfaces (Library)

Main Thread

Route Manager

Routing Table

ALN-Port Manager

Port Table

Internal Server th.

Internal Server Child th.s

Networks

Route Exchanger th.

Connection RedirectorParent th.

ConnectionRedirectorChild th.Connection Redirectors

ClientApplication

ServerApplication

ConnectionServer th.s

L1-4 (unix_serial) Multiplexer

L1-4 (unix_ip) L1-4 (linux_irda) L1-4 (internal_unix)

Socket(AF_INET) Socket(AF_IRDA) Device File

TCP/IP

Ethernet

IrTTP/LMP/LAP

IrPHY

Com Port

Serial

Socket(AF_UNIX)

IPC

ALN-HCL-Server Application

libHCL

ALN Transport Interface

Kern

el

User

Level

ALN-MCL Implementation User-level library implementation in Java Compatible with standard Java1.1 Socket

API Additional methods for explicit connection

redirection: suspend() and resume() Mobility notification event:

MobilityEvent Applicable to mobile applications

MobileSocket library itself can migrate with applications with Java Object Serialization mechanism

MobileSocketfor Mobile Applications

“Serializable” MobileSocket classfor Mobile Applications and Agents

AppBAppB

Host-B

Host-A

AppAAppA

AppA’ObjectSerialization

MSockA (SocketX)

MSockA (SocketY)

Host-C

4.Evaluations

Comparisons with related works based on other approaches (1) Communication

transparency (2) Communication continuity

Related Approaches

Application Layer

Transport Layer

Network Layer

Datalink Layer

Physical LayerL1

L2

L3

L4

L5 ALN, Proxies, GIOP

IP-Masquerade

NAT, IP over x

CommunicationTransparency

CommunicationContinuity

ALN, MSOCKS

TCP-R

Mobile IP

Comparisons

(1) Communication Transparency

ALN-HCL IP ApproachComm.Transparency Heterogeneous Network Applicable Applicable Scalability limited globalMechanism Code Size small large Portability high low Adoption for New net. easy difficult

Further Functionality Internet Access possible originalProcessing at Intermediate Hosts suitable not suitable

Comparisons

(1) Communication Continuity

MobileIP TCP-R MSOCKS MCLComm.Continuity Virtual Circuit Comm. Limited OK Limited OK Datagram Comm. OK OK OK OK

Implementation Layer3 Layer4 Layer5 Layer5

Modification for necessary necessary necessary unnecessaryLayer1-4 Protocols

Optional Software HA, FA - Proxy -

Mobile Application No No No YesSupport

5.Conclusion Network environment for VNA

Heterogeneity of hosts and networks Mobility

ALN provides Communication transparency Communication continuity for applications

Application layer approach Applicability for heterogeneous hosts and

networks Enables both virtual circuit and datagram

communication continuity Simplified and minimized implementation Effective for mobile applications or agents

Future Work

Communication transparency Optimization of Implementation QoS-aware transport for applications Application layer functionalities at the

intermediate hosts (i.e., Accounting, Active processing)

Communication continuity Disconnected operation

with application-side customization

Publications Okoshi, T., Tobe, Y. and Tokuda, H.: MobileSocket: Library based

Continuous Operation Support for Java Applications, 第 2 回プログラミングおよび応用のシステムに関するワークショップ (SPA‘99), 日本ソフトウエア科学会 (1999).

Okoshi, T., Mochizuki, M., Tobe, Y. and Tokuda, H.: MobileSocket: Toward Continuous Operation for Java Applications, In Proceedings of IEEE 8th International Conference on Computer Communications and Networks (ICCCN), IEEE Communication Society, pp. 50-57 (1999).

Okoshi, T., Mochizuki, M., Tobe, Y. and Tokuda, H.: MobileSocket: Session Layer Continuous Operation Support for Java Applications, 情報処理学会論文誌 , Vol.40, No.6, pp.2573-2584 (2000).

大越匡 , 中澤仁 , 田村陽介 , 望月祐洋 , 戸辺義人 , 西尾信彦 , 徳田英幸 : VNA ：仮想情報家電の実現へ向けて , 第 59 回情報処理学会全国大会 (1999).

中澤仁 , 大越匡 , 望月祐洋 , 徳田英幸 : VNA 構築用ライブラリの設計と実装 , 第 59 回情報処理学会全国大会 (1999).