Collaboration and GridTechnologies

Geoffrey FoxProfessor of Computer Science, Informatics, Physics

Pervasive Technology Laboratories

Indiana University Bloomington IN 47401

gcf@indiana.edu

http://www.infomall.org

http://www.grid2002.org

What we can discuss Grid and Collaboration Tools and Architectures which

can address some difficulties encountered upto now in areas like distance education

Audio-Video conferencing addressing network difficulties and the integration of different approaches

Sharing material over the Internet• Shared display collaboration

Producing web pages using “re-usable” portlet architecture

Tools are in “alpha” release at moment• So they might be less reliable than unreliable tools they are

trying to improve

2/22/2001 JSUFall97Master http://www.npac.syr.edu

gcf@npac.syr.edu1

Programming for the WebProgramming for the WebGeneral IntroductionGeneral Introduction

Course at Jackson State University Spring98 Course at Jackson State University Spring98 and Fall 97and Fall 97

http://www.npac.syr.edu/users/gcf/jsufall97introNancy McCracken

Geoffrey Fox, Tom Scavo

Syracuse University NPAC

111 College PlaceSyracuse NY 13244 4100

3154432163

JSU

Syracuse

Teaching Jackson State Fall 97 to Fall 2001

Spring 2004: Course on “e-Science”/Grid

Distance Learning …..• Linking teachers to students remotely• Linking students/mentors to students/mentors for

collaboration at a distance on a project• Collaboration is sharing

– People (audio, video, text chat, instant messenger)– Web Pages– Other electronic resources (e.g. Word running on laptop)– Homework– Grades

• Asynchronous: I post a web page; you access it– I send email– Can recover from temporary network glitches

• Synchronous: I post an electronic document; you see what I post (in a second or two)– As I update, you get update– Very sensitive to network glitches

Problems from Tango and all Others Clients were unreliable – addressed by better windows and

moving collaboration from Browser to an application Networks were unreliable and firewalls are a problem

• Not a lot of progress with QoS at network level• Some QoS problems are due to different collaboration

streams interfering• Use application level QoS with highly robust managed

messaging Very hard to customize each application in “shared state event

model”• Offer shared display• Convert Applications to Web Services

Many different standards H323, SIP, Access Grid, T120 …• Unify as single XML standard

Inconvenient to customize user interfaces• Use portlet technology supporting desktop and PDA clients

Collaboration and Web Services Collaboration has

a) Mechanism to set up members (people, devices) of a “collaborative sessions”

b) Shared generic tools such as text chat, white boards, audio-video conferencing

c) Shared applications such as Web Pages, PowerPoint, Visualization, maps, (medical) instruments ….

b) and c) are “just shared objects” where objects could be Web Services but rarely are at moment

• We can port objects to Web Services and build a general approach for making Web services collaborative

a) is a “Service” which is set up in many different ways (H323 SIP JXTA are standards supported by multiple implementations) – we should make it a WS

Shared Event Collaboration All collaboration is about sharing events defining state changes

• Audio/Video conferencing shares events specifying in compressed form audio or video

• Shared display shares events corresponding to change in pixels of a frame buffer

• Instant Messengers share updates to text message streams

• Microsoft events for shared PowerPoint (file replicated between clients) as in Access Grid

Finite State Change NOT Finite State Machine architecture Using Web services allows one to expose updates of all kinds as

messages• “Event service” for collaboration is similar to Grid notification service and we

effectively define SDE’s (service data elements) in OGSI

Group (Session) communication service is needed for the delivery of the update events• Using Event Messaging middleware makes messaging universal

Global-MMCS 2.0 XGSP based MCU We are building an open source protocol independent Web

Service “MCU” which will scale to an arbitrary number of users and provide integrated thousands of simultaneous users collaboration services.

We will deploy it globally and hope to test with later this year. The function of A/V media server will be distributed using

NaradaBrokering architecture.• Media Servers mix and convert A/V streams

Open Global-MMCS MCU based on the following open source projects• openh323 is basis of H323 Gateway• NIST SIP stack is basis of SIP Gateway• NaradaBrokering is open source messaging from Indiana• Java Media Framework basis of Media Servers (needs

performance enhancement)

XGSP Web Service MCU Architecture

SIP H323 Access Grid Native XGSPAdmire

Gateways convert to uniform XGSP Messaging

High Performance (RTP)and XML/SOAP and ..

Media ServersFilters

Session ServerXGSP-based Control

NaradaBrokeringAll Messaging

Use Multiple Media servers to scale to many codecs and manyversions of audio/video mixing

NB Scales asdistributed

WebServices

NaradaBrokering

Polycom, Access Grid and RealVideo views of multiple streams using

A/V Web Service integrating SIP and H323

Features of A/V Conferencing Need a video camera – Polycom ViaVideo or Logicon Plantronics or similar echo-canceling microphone such

as Viavideo VRVS or GlobalMMCS does not need hardware

multicast• Messenging in GlobalMMCS very powerful• Software multicast will IMHO replace hardware multicast

Access Grid supports multiple video cameras but no special reason one needs four – depends on application

Web service will mosaic multiple streams into one• Allow Polycom to receive multiple streams

RealVideo for most reliability as 10 second buffer

NaradaBrokering

Minicomputer

Firewall

ComputerServer

PDA

Modem

Laptop computerWorkstationPeers

Peers

Audio/VideoConferencing Client

Audio/VideoConferencing Client

NaradaBrokering BrokerNetwork

BrokersONLYprocessmessages

Grid Messaging Substrate

Consumer Service

SOAP+HTTPRMI TCP/IPRTP ….

Messaging Substrate

Consumer Service

Standard client-serverstyle communication.

Substrate mediatedcommunication removestransport protocoldependence.

SOAP+HTTPRMI TCP/IPRTP ….

Any Protocols satisfying QoS

Messaging Substrate has “intelligence”, “any desired fault tolerance” “logging” etc.

“GridMPI” v. NaradaBrokering In parallel computing, MPI and PVM provided “all the features

one needed’ for inter-node messaging NB aims to play same role for the Grid but the requirements and

constraints are very different• NB is not MPI ported to a Grid/Globus environment

Typically MPI aiming at microsecond latency but for Grid, time scales are different• 100 millisecond quite normal network latency• 30 millisecond typical packet time sensitivity (this is one audio or video

frame) but even here can buffer 10-100 frames on client (conferencing to streaming)

• <1 millisecond is time for a Java server to “think” Jitter in latency (transit time through broker) due to routing,

processing (in NB) or packet loss recovery is important property Grids need and can use software supported message functions and

trade-offs between hardware and software routing different from parallel computing

NaradaBrokering Based on a network of cooperating broker nodes

• Cluster based architecture allows system to scale in size• Grid routing topologies are open research issue?

Originally designed to provide uniform software multicast to support real-time collaboration linked to publish-subscribe for asynchronous systems.

Perhaps better thought of as stream not message handler Now has several core functions

• Reliable order-preserving “Optimized” Message transport (based on performance measurement) in heterogeneous multi-link fashion with TCP, UDP, SSL, HTTP, and will add GridFTP

• General publish-subscribe including JMS & JXTA and support for RTP-based audio/video conferencing

• General software routing to avoid network problem• Distributed XML event selection using XPATH metaphor• QoS, Security profiles for sent and received messages• Interface with reliable storage for persistent events

Laudable Features of NaradaBrokering Is open source http://www.naradabrokering.org available now;

major new release for SC03 Will have end-point “plug-in” as well as standalone brokers

• end-point is service or user-interface machine Will have a discovery service to find nearest brokers Does tunnel through most firewalls without requiring ports to be

opened Links to NWS (Network Weather Service) style performance

estimation systems Supports JXTA (peer-to-peer network), JMS (Java Message

Service) and more powerful native mode Transit time < 1 millisecond per broker Will have setup and broker network administration module

NaradaBrokering Naturally Supports Filtering of events (streams) to support different end-point

requirements (e.g,. PDA versus desktop, slow lines, different A/V codecs)

Virtualization of addressing, routing, interfaces (OGSI versus pure Web services for example)

Federation and Mediation of multiple instances of Grid services as illustrated by • Composition of Gridlets into full Grids (Gridlets are single computers in

P2P case)

• JXTA with peer-group forming a Gridlet

Monitoring of messages for Service management and general autonomic functions

Fault tolerant data transport Virtual Private Grid with fine-grain Security model

Performance Test : GlobalMMCS1.0 We conducted extensive performance tests on audio and video

servers. Video:

• The test shows that our video server is capable of supporting 100-300 clients if there is only one video sender.

• Video Server Machine : 1.2GHz Intel Pentium III dual CPU, 1GB MEM, RedHat Linux 7.3

Audio: • Our tests show that audio server can support 5 concurrent

sessions (250 participants in total) without any packet droppings. • Audio Server Machine: 2.5GHz Pentium 4 CPU, 512MB memory,

Windows XP machine Scale with logarithmic Broker network

0

10

20

30

40

50

60

0 200 400 600 800 1000 1200 1400 1600 1800 2000

De

lay

(Mill

ise

con

ds)

Packet Number

Average delays per packet for 50 video-clients NaradaBrokering Avg=2.23 ms, JMF Avg=3.08 ms

NaradaBrokering-RTP JMF-RTP

0

1

2

3

4

5

6

7

8

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Jitte

r (

Mill

ise

con

ds)

Packet Number

Average jitter (std. dev) for 50 video clients.

NaradaBrokering Avg=0.95 ms, JMF Avg=1.10 ms

NaradaBrokering-RTP JMF-RTP

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Jitt

er

(M

illis

eco

nd

s)

Packet Number

900 audio clientsNaradaBrokering-RTP

JMF-RTP

Commercial Collaboration

Systems

Placeware

WebEx

Centra Anabas

Robust Web Service Model However hard we work, there will be disconnects and problems Typically difficulty is client and client/server network So we are designing a backup with a web page version of

collaborative page – shared display, text chat etc.• And using instant messenger as backup control function

Have this working (roughly) for Shared PowerPoint but need to extend to other functions

SynchronizationServer (NB)

BackupWeb Service

Fancy Collaboration Backup HTMLInstant Messenger

Collaboration

Application Web Service Model Anabas provides shared display (frame-buffer) as this

works for all applications Shared event is how Tango used to it and this is Access

Grid PowerPoint model• Share events like “New Slide” or “New File”

Our strategy is to convert applications to Web Services and use these to produce shared event• Using NaradaBrokering as system to share events

Have implemented for Scalable Vector Graphics (SVG) and PowerPoint (partially as Microsoft makes hard)

Will extend to OpenOffice if pratical

Web Service Model for Application Development

User Interface

Raw (UI) Events

Logic of Application

Semantic Events

Data

User FacingPorts

Resource Facing Ports

Events as Messages

Rendering as Messages

View

Control

Model

MessagingSystem

Interrupts in traditional monolithic applications become“real messages” not directly method callsNatural for collaboration and universal access

Application as a Web serviceApplication as a Web service

Participating Client

RenderingRendering

User Interface

W3C DOM Events

From Master

FromCollaborationAs a WS

Events

Application as a Web serviceApplication as a Web service

Master Client

RenderingRendering

User Interface

W3C DOM Events

To Collaborative Clients

FromCollaborationAs a WS

Events

Control flow for collaborative SVG clients

Figure 3 Control flow for collaborative SVG clients

Collaborative SVG As A Web Service

NaradaBrokering

SVGBrowser

SVGBrowser

SVGBrowser

SVGBrowser

Identical Programs receiving identical eventsToken determines if browser is moving, waiting for opponent or an observer

SIMD Collaboration

SVGViewer

SVGViewer

SVGViewer

SVGViewer

SVG Model (DOM)

NaradaBrokering

Shared Output portSIMD CollaborativeWeb Service

Non Web ServiceImplementation

NaradaBrokering

MIMD Collaboration

SVGViewer

SVGViewer

SVGViewer

SVGViewer

NaradaBrokering

Shared Input portMIMD CollaborativeWeb Service

SVG Model

SVG Model

SVG Model

SVG Model

NaradaBrokering

PowerPoint as a Sort of Web Service

MasterClient

ConnectableObject

Sink

NaradaBrokering Message Service

User1

1

User2

Usern

PPT as a Web Service

As in Access Grid CollaborativeClient

Holds meta-data(sample of high level semanticevents) like slide number and title

Integration of PDA, Cell phone and Desktop Grid Access

Portals and Web Services Web Services allow us to build a component model (see

CCA) for resources. Each resource naturally has a user interface (which

might be customized for user) Web Service <--> Portlet Natural to use a component model for portal building

displayed web page from collection of portlets• So can customize each portlet and customize which portlets

you want Apache Jetspeed seems good open source technology

supporting this model • Being used by NCSA and DoD HPCMO

WSRP Structure of a Portlet Each Web Service naturally has a user interface specified as “just another

port” This gives each Web Service a Portlet view specified (in XML as always) by

WSRP (Web services for Remote Portals) So component model for resources “automatically” gives a component model

for user interfaces• When you build your application, you define portlet at same time

Application orContent source

WSDL

Web Service

S

R

W

P

Application as a WSGeneral Application Ports Interface with other Web Services

User Face ofWeb ServiceWSRP Ports define WS as a Portlet

PortalUser ProfileAggregate

UI Fragments

Client

WSRP isWeb Services for Remote Portals1st Meeting OASIS March 18 2002

WSDisplay

WSViewer

WS Display

WS Viewer

Event(Message)

Service

Master

WSDisplay

WS Viewer

Web Service MessageInterceptor

Collaboration as a WSSet up Session with XGSP

Application orContent source

WSDL

Web Service

F

I

U

O

F

I

R

O

Shared Output Port Collaboration

OtherParticipants

Text ChatWhiteboardMultiplemasters

WSDisplay

WSViewer

WS Display

WS ViewerEvent

(Message)Service

Master

WSDisplay

WS Viewer

Collaboration as a WSSet up Session with XGSP

WebServic

e

F

I

U

O

F

I

R

O

Shared Input Port (Replicated WS) Collaboration

OtherParticipants

WebServic

e

F

I

U

O

F

I

R

O

WebServic

e

F

I

U

O

F

I

R

O

Collage of Portals

Earthquakes – NASAFusion – DoEComputing Info – DoDPublications -- CGL

Web Services as a Portlet• Each Web Service naturally has a

user interface specified as “just another port” – Customizable for universal access

• This gives each Web Service a Portlet view specified (in XML as always) by WSRP (Web services for Remote Portals)

• So component model for resources “automatically” gives a component model for user interfaces– When you build your

application, you define portletat same time

Application orContent source

WSDL

Web Service

S

R

W

P

Application as a WSGeneral Application PortsInterface with other WebServices

User Face ofWeb ServiceWSRP Ports define WS as a Portlet

Web Services have other ports (Grid Service) to be OGSI compliant

Online Knowledge Center built from Portlets

• Web Services provide a component model for the middleware (see large “common component architecture” effort in Dept. of Energy)

• Should match each WSDL component with a corresponding user interface component

• Thus one “must use” a component model for the portal with again an XML specification (portalML) of portal component

A set of UIComponents

PortletPortlet PortletPortlet PortletPortlet PortletPortlet

XMLRSS, OCS, or otherLocal or remote

HTMLLocal files

JSP or VMLocal templates

WebPageRemote HTML

PortletPortlet

PortletsUser implementedusing Portal API

Portlets

Data

PortletController PortletController

Screen Manager

HTML

PSML

PortletControl

ECS

JSP template

ECS ECS ECS ECS

ECS ECS ECS

ECS Root to HTML

ECS

Turbine ServletJetspeedArchitecture

Portlets and Portal Stacks

• User interfaces to Portal services (Code Submission, Job Monitoring, File Management for Host X) are all managed as portlets.

• Users, administrators can customize their portal interfaces to just precisely the services they want. Core Grid Services

User facing Web Service Ports

Application Grid Web Services

Aggregation Portals(Jetspeed)

Messa

ge S

ecu

rity, In

form

atio

n

Serv

ices

IU and OGCE Portal ArchitectureC

lient

s (P

ure

HT

ML,

Jav

a A

pple

t ..

)

Agg

rega

tion

and

Ren

derin

g

JetspeedInternalServices

Portlet Class:IFramePortlet

Portlet Class:VelocityPortlet

Portlet Class:JspPortlet

Portlet Class:WebForm

Gateway(IU)

Web/Gridservice

Web/Gridservice

Web/Gridservice

Computing

Data Stores

Instruments

GridPortTexas

(Java)COG Kit

Clients Portal Portlets Libraries Services Resources

LocalPortlets

Remoteor ProxyPortlets

EmphasisLargely taken

from other projects

(Jetspeed)

Hierarchical arrangement

Jetspeed Computing Portal: Choose Portlets

4 available portletslinking to Web ServicesI choose two

Choose Portlet Layout

Choose 1-column Layout

Original 2-column Layout

Lists user files on selected host, noahsark.File operations include

Upload, download, Copy, rename, crossload

Tabs indicate availableportlet interfaces.

File management

Sample page with several portlets:

proxy credential manager,submission, monitoring

Provide information about application

andhost parameters

Select applicationto edit

Administer Grid Portal