Collaboration and Web Services

Collaboration and Web Services
UIUC October PTLIU Laboratory for Community Grids Geoffrey Fox Computer Science, Informatics, Physics Indiana University, Bloomington IN 47404 (Technology Officer, Anabas Corporation, San Jose) 9/19/2018 uri="

Some Basic Observations/Goals
Technology Support for e-learning is one motivation Need Synchronous and Asynchronous Resource Sharing Can provide universal access using synchronous collaboration technology Grids manage and share asynchronous resources in a rather centralized fashion Peer-to-peer networks are “just like” Grids with different implementations of services like registration and look-up Web Services interact with messages Everything (including applications like PowerPoint will be a WS?) Computers are fast and getting faster. One can afford many strategies that used to be unrealistic All messages can be publish/subscribe Software message routing XML will be used for most interesting data and meta-data One will store/consider data and meta-data separately but often use same technology to manage both of them. 9/19/2018 uri="

uri="http://www.naradabrokering.org" email="gcf@indiana.edu"
Deductions The system consists of a sea of message-based Services Services inject and extract messages whose transport and manipulation is support by a logically distinct sea of brokers/routers They support adaptive routing, filtering, workflow … They separate logical and actual transport These form a federated XML database and support asynchronous collaboration These process real-time messages in about a millisecond and support synchronous collaboration Basic Unit of information (including events and messages) is a bunch of XML using URI’s to link to other XML or to “other technology capabilities” – Fortran programs, video files, telescopes … This XML includes service meta-data, user profiles, H323 done right, your homework grades, update of framebuffer in shared display etc. 9/19/2018 uri="

So what are we doing I? We need to be UIUC to do all of this and I can only do a few scattered projects based on this model We have designed and built a messaging infrastructure NaradaBrokering embodying some of these ideas We have shown interoperability between JXTA (Sun’s P2P environment), Java Message Service (JMS) and NaradaBrokering We have deployed a classic (Placeware, Interwise, WebEx) synchronous collaboration environment (Garnet) using JMS or Narada (uses Anabas technology) We have illustrated filtering/universal access by linking PDA’s to desktop collaboration We have prototyped audio-video conferencing as a web service We are repackaging collaborative SVG as a Web service to illustrate (explore) how wonderful it will be when all applications are Collaborative Web services 9/19/2018 uri="

So what are we doing II? but won’t mention again
We are building a toolkit to allow any application to be made a Web service (this only manipulates metadata) Aimed at support of classic Grid applications running on a backend supercomputer A Computing Portal We are building Jetspeed portlets of various types – including collaborative We have some XML news group technology which uses news group interface to support management and browsing of multiple XML information nuggets (instances) of general Schema Wizard generates interfaces to define nuggets JSP wizard layout and browsing specification defined by annotating Schema 9/19/2018 uri="

Classic Grid Architecture
Resources Database Database Content Access Composition Middle Tier Brokers Service Providers Netsolve Security Collaboration Computing Middle Tier becomes Web Services Clients Users and Devices 9/19/2018 uri="

Different Web Service Organizations
Everything is a resource (distributed object) implemented as a Web Service, whether it be: back end supercomputers and a petabyte dataset Microsoft PowerPoint and this file Web Services communicate by messages ….. Web Services are “just distributed objects” with focus on (particular) XML specified input and output messages Grids and Peer to Peer (P2P) networks can be integrated by building both in terms of Web Services with different (or in fact sometimes the same) implementations of core services such as registration, discovery, life-cycle, collaboration and event or message transport ….. Gives a Peer-to-Peer Grid Roughly but not completely consistent with OGSA Consistent with “rule”: build everything as a Web service 9/19/2018 uri="

Peer to Peer Grid Peers Peers A democratic organization
Database Database Peers Service Facing Web Service Interfaces Event/ Message Brokers Peer to Peer Grid Peers User Facing Web Service Interfaces A democratic organization Peer to Peer Grid 9/19/2018 uri="

Education as a Web Service
“Learning Object” XML standards already exist from IMS/ADL – need to update architecture Web Services for virtual university include: Registration Performance (grading) Authoring of Curriculum Online laboratories for real and virtual instruments Homework submission Quizzes of various types (multiple choice, random parameters) Assessment data access and analysis Synchronous Delivery of Curricula including Audio/Video Conferencing and other synchronous collaborative tools as Web Services Scheduling of courses and mentoring sessions Asynchronous access, data-mining and knowledge discovery Learning Plan agents to guide students and teachers 9/19/2018 uri="

Collaboration and Web Services
Collaboration has Mechanism to set up members (people, devices) of a “collaborative sessions” Shared generic tools such as text chat, white boards, audio-video conferencing Shared applications such as Web Pages, PowerPoint, Visualization 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 can make it a WS quite easily 9/19/2018 uri="

Web Service Architecture for Audio Video Conferencing
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XGSP: Introduction Registration Method Session Command Query Session Channel Binding Method Collaboration as a WS Registration Method registration server with its alias name and current location Session Command Method Membership Control Commands, Session Control Commands Query Method discover various properties about the system Session Channel Binding Method (Specific to A/V) bind the RTP channels of a client into the media server 9/19/2018 uri="

XGSP: Example <SessionDes> <SessionName> PervasiveTech Seminar </SessionName> <SessionID> </SessionID> <SessionCreator> </SessionCreator> <SessionInfo> this is a meeting on the XGSP </SessionInfo> <SessionPlace> Lobby Room </SessionPlace> <SessionTime> <StartTime> (EastTime) 10:00AM </StartTime> <EndTime> (EastTime) 12:00AM </EndTime> </SessionTime> <SessionURI> </SessionURI> <SessionParticipants> <Participant> </Participant> <Participant> </Participant> <Participant> </Participant> </SessionParticipants> <ContactInfo> </ContactInfo> </SessionDes> 9/19/2018 uri="

Linking Clients and Servers
Current Implementation Polycom (H323) Access Grid Integration Future Project Link Proprietary MCU’s Illustrated for SIP (HearMe) and Access Grid 9/19/2018 uri="

Current Status XGSP Specification stable Demo prototype of Polycom (H323), Access Grid, Shared Display clients H323 Gateway based on openh323 JMF (Java Media Framework) used for Media Server XGSP used Internally between audio, video and session control services Codec negotiation supported (No XGSP clients yet) Narada UDP Communication has been successfully tested XGSP MCU (Control) User Interface 9/19/2018 uri="

H323 Client (Polycom) in XGSP Session
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Comparison with other approaches
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Possible A/V Web Service Futures
Productize Narada Integration – needs more testing of Narada multi-protocol interface Will this defeat firewalls that currently spoil my lectures? Session Control Server can be used to define collaborative sessions for other shared applications Text chat etc. Shared SVG, StarOffice, Internet Explorer, Word etc. (using “.net” event interface) Integrate with JXTA interface using Narada-JXTA link Add RealMedia (Windows Media) SIP (VOIP) and native XGSP clients Integrate at server (MCU) level for Polycom, AccessGrid, VOIP – this is Federation 9/19/2018 uri="

Personal View of Collaborative Systems
Originally (at Syracuse) built a collaborative environment Tango and used for online lectures and training sessions from (2001 updated system) Functionality fine but browser interface and network produced instability Hard to build custom collaborative applications Newer simpler (Garnet) system addresses these issues although network issues still being addressed Use of XML meta-data and building Education or e-learning as a set of Web Services gives interoperability Use of Grid (as from IBM) and peer-to-peer technology will give improved infrastructure (still quite primitive) 9/19/2018 uri="

Courses at Jackson State
Taught using Tango/Garnet since fall 97 over Internet twice a week from Syracuse/FSU/Indiana Course material same style as online material for in-university classes Curricula, Homework, Grading, Facilities done by “me” Students get JSU NOT Syracuse/Indiana Credit “Trivial” in that learning model identical to that in traditional courses – just changed interaction mode Jackson State major MSI (Minority Serving) University with many computer science graduates Do not compete with base courses but offer addon courses with “leading edge” material (Web Technology, modern scientific computing) which give JSU (under)graduates skills that are important in their career Fall 99 Semester CPS640 offered to 40 students in 5 distant places and separately 40 at Syracuse 9/19/2018 uri="

Lessons from Past “True” Shared Event flexible but too much work for most cases Shared Display – nearly always works Shared Export – SVG PDF HTML X3D etc. can be re-used Integrate synchronous and asynchronous collaboration Do not build into browser as not a reliable or standard virtual machine Build around uniform publish-subscribe style XML Event Model supporting archiving, customization, filtering – apply to all collaboration modes Later we realized need to integrate with Peer to Peer and Web Services (straightforward as XML event model fits these architectures) 9/19/2018 uri="

User Facing Ports for Web Service
Content Provider WSDL Web Service F I U O R Portal Aggregate WS-User Facing Fragments Render Other WS User Facing Ports Other WS Resource or Service-facing Ports User-facing Ports 9/19/2018 uri="

Collaboration: Shared Display
Sharing can be done at any point on “object” or Web Service pipeline Shared Web Service Shared Display Shared Event Shared Export Object Object’ Object’’ Object Display Object Viewer Master Shared Display shares framebuffer with events corresponding to changed pixels in master client. Event (Message) Service Object Display As long as pipeline uses messages, easy to make collaborative Windows framebuffers and in fact most applications do NOT expose a message based update interface Object Display 9/19/2018 uri="

Event (Message) Service
Shared Input Port (Replicated WS) Collaboration Collaboration as a WS Set up Session with XGSP Web Service F I U O R WS Display WS Viewer Master Web Service F I U O R WS Display WS Viewer Event (Message) Service Other Participants Web Service F I U O R WS Display WS Viewer 9/19/2018 uri="

Event (Message) Service
Shared Output Port Collaboration Collaboration as a WS Set up Session with XGSP Web Service Message Interceptor Master Application or Content source WSDL Web Service F I U O R WS Display WS Viewer WS Viewer WS Display Text Chat Whiteboard Multiple masters Event (Message) Service Other Participants WS Viewer WS Display 9/19/2018 uri="

Role of Event/Message Brokers
We will use events and messages interchangeably An event is a time stamped message Our systems are built from clients, servers and “event brokers” These are logical functions – a given computer can have one or more of these functions In P2P networks, computers typically multifunction; in Grids one tends to have separate function computers Event Brokers “just” provide message/event services; servers provide traditional distributed object services as Web services There are functionalities that only depend on event itself and perhaps the data format; they do not depend on details of application and can be shared among several applications NaradaBrokering is designed to provide these functionalities MPI provided such functionalities for all parallel computing 9/19/2018 uri="

NaradaBrokering implements an Event Service
Web Service 1 (Virtual) Queue Web Service 2 Destination Source Matching Filter Routing workflow WSDL Ports Broker Filter is mapping to PDA or slow communication channel (universal access) – see our PDA adaptor Workflow implements message process Routing illustrated by JXTA and includes firewall Destination-Source matching illustrated by JMS using Publish-Subscribe mechanism These use Security model (being designed) based on WS-Sec 9/19/2018 uri="

Engineering Issues Addressed by Event / Messaging Service
Application level Quality of Service – give audio highest priority Tunnel through firewalls Filter messages to slow (collaborative or real time) clients Hardware multicast is erratically implemented (Event service can dynamically use software multicast) Scaling of software multicast Elegant implementation of Collaboration in a Groove Networks (done better) style Integrate synchronous and asynchronous collaboration 9/19/2018 uri="

Features of Event Service I
MPI nowadays aims at a microsecond latency The Event Web Service aims at a millisecond (computer) latency Typical distributed system travel times are many milliseconds (to seconds for Geosynchronous satellites) Different performance/functionality trade-off Messages are not sent directly from P to S but rather from P to Broker B and from Broker B to subscriber S Actually a network of brokers Synchronous systems: B acts as a real-time router/filterer Messages can be archived and software multicast Asynchronous systems: B acts as an XML database and workflow engine Subscription is in each case, roughly equivalent to a (XML) database query 9/19/2018 uri="

Features of Event Service II
In principle Message brokering can be virtual and compiled away in the same way that WSDL ports can be bound in real time to optimal transport mechanism All Web Services are specified in XML but can be implemented quite differently Audio Video Conferencing sessions could be negotiated using SOAP (raw XML) messages and agree to use certain video codecs transmitted by UDP/RTP Separate logical User Channel and its protocol from “actual ports/protocols” which are Transport Channels Use Performance Service to map user requirements into transport e.g. audio user channel requests UDP from A to B but we use TCP/IP on port 80 from A to N1 (through nasty firewall) and UDP from N1 to B (say on Internet2) There is a collection of XML Schema – call it GXOS – specifying event service and requirements of message streams and their endpoints 9/19/2018 uri="

Features of Event Service III
The event service is naturally implemented as a dynamic distributed network Required for fault tolerance and performance Implies a corresponding dynamic distributed XML database A new classroom joins my online lecture A broker is created to handle students – multicast locally my messages to classroom; handle with high performance local messages between students Company X sets up a firewall The event service sets up brokers either side of firewall to optimize transport through the firewall Note all message based applications use same message service Web services imply ALL applications are (possibly virtual) message based 9/19/2018 uri="

Single Server P2P Illusion
Traditional Collaboration Architecture e.g. commercial WebEx Data base Collaboration Server 9/19/2018 uri="

Narada Broker Network (P2P) Community For message/events service Broker Broker (P2P) Community Resource Broker Broker Broker Data base (P2P) Community Software multicast Broker (P2P) Community 9/19/2018 uri="

NaradaBrokering and JMS (Java Message Service)
Low Rate; Small Messages (commercial JMS) 9/19/2018 uri="

NaradaBrokering and JXTA
Narada-JXTA provides JXTA guaranteed long distance delivery Request/Response Present if targeted at Particular peer Narada JXTA Event 9/19/2018 uri="

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NaradaBrokering Communication
Applications interface to NaradaBrokering through UserChannels. UserChannels are implemented as TransportChannels which are made up of Links UserChannels have publish/subscribe semantics Links implement a single conventional “data” protocol supported by a SOAP administrative channel Easily adding new transport protocols within the Framework. Negotiating the best available communication protocol Link implementations can incorporate their own handshaking protocols for setting up of the communication channel. Different links can have different underlying transport implementations Implementations in the next release will include support for TCP,UDP, Multicast, SSL, HTTP, HTTPS. Support communication through proxies such as iPlanet, Netscape Support for communication through firewalls such as Microsoft ISA. NaradaBrokering brokers and Links can be instantiated dynamically Support communication between two application end points across firewall & proxy boundaries. 9/19/2018 uri="

User “XML Database” 9/19/2018 uri="

Narada Performance Web Service
Performance measurements are used by Links in Reconfiguring Connectivity between nodes Deciding underlying transport protocol Determining possible filtering TransportChannel uses “performance heuristic” to define links and their protocols Factors measured include Transit delays, bandwidth, Jitter, Receiving rates. Performance measurements are Spaced out at increasing intervals for healthy channels. Factors selectively measured for unhealthy channels. No repeated measurements of bandwidth for example. Injected into Narada network as XML events Administrative Interface 9/19/2018 uri="

Narada Link Firewall Architecture
Control Channel (TCP) Specifics tunnel destination, parameters. [ SOAP port 80 ] Config Specifics default tunnel destination, parameters. Non-Firewall Proxy CTL SSL Tunnel Server Proxy UDP TCP SSL Tunnel Client Proxy SSL Lib API TCP UDP Firewall Proxy Fake SSL Impl. JSSE Impl. WinINET Impl. Proxy Detection API Required for MS Authentication support. Text Config WinINET Detection Required for Proxy location detection Narada Link Firewall Architecture 9/19/2018 uri="

Start UDP Works Stream Media Types Connection Complete Doesn’t Work Start TCP Works Reliable Data Stream Doesn’t Work Windows ? WinINET Try SSL first then HTTP Works NaradaBrokering Link Transport Firewall Heuristic Doesn’t Work Try SSL Over HTTPS Proxy Does HTTPS Proxy Exist Works Yes Doesn’t Work Try HTTP Over HTTP Proxy Does HTTP Proxy Exist Works Yes Doesn’t Work “Fake” SSL Over Direct Try SSL Over Direct Try HTTP Direct Works Doesn’t Work Doesn’t Work Works 9/19/2018 uri="

Roles of NaradaBrokering
Originally to provide uniform software multicast to support real-time collaboration linked to publish-subscribe for asynchronous Until recently used JMS “instead” but have replaced by NB as we can control features (bugs) in implemenation Now has three major core functions Message transport (based on performance) in multi-link fashion General publish-subscribe including JMS&JXTA Federation of multiple instances (just starting) of Grid services 9/19/2018 uri="

Federation of Services
If you have a service – Notification (as with Grid or JXTA advertisements), Search, Scheduling, Audio-Video conferencing …. With a standard which client and server components Then can build a “server” that services all clients Alternatively can hierarchically consider collection of existing Server-client domains IBM or Globus OGSA islands Sun Grid Engine Schedulers Polycom/Access Grid A/V sessions Enterprise Search Engines Federation links islands together JXTA Search has XML specified federation approach – will try to include and generalize as a NaradaBrokering federation framework DoD High Level Architecture HLA does this for simulation NB Hub 9/19/2018 uri="

Narada/JMS and Collaboration
Collaboration involves sharing resources and synchronous collaboration involves coordinating a common view of a resource between multiple clients Typically one client is “in charge” and others get initial and updated resource from this “master” Specification of initial state of resource and its change are “just XML events” and we (Anabas and Indiana) have used first JMS and now NaradaBrokering to implement the transport of update events between collaborating clients Update events include: text you type into text chat or Instant Messenger URL defining shared browser Change in framebuffer for (most flexible) shared display Microsoft events for shared PowerPoint (file replicated between clients) 9/19/2018 uri="

Commercial Collaboration Systems
Centra Anabas WebEx PlaceWare 9/19/2018 uri="

Filtering Service As (real-time) collaboration uses publish-subscribe, we can and in fact must map/filter “object renderings” or updates to them differently for each class of client In distance education, needed for example to Cope with mix of Internet2 and dial-up clients (the student who overslept and is at home) Allow PDA’s (Personal Digital Assistants) and desktops to be in same session To allow Blind users to select the purely audio version of some content Mapping in event service enables universal access Note clients’ subscription to publish/subscribe service includes “user profile” 9/19/2018 uri="

Collaborative PDA Extendable to more general universal access Can implement filter either as an insertion in message stream or in batch mode where a Service subscribes to event stream (one collaborative application or “sharedlet”), filters it and reposts to a different stream We developed first case with a special adaptor that is essentially a NaradaBrokering node that Has added filters controlled by client profile Has stripped down special purpose link protocol HHMS (Hand held message service) optimized for PDA Currently implemented as MyProfessor for Windows CE iPAQ Working on Palm OS Cell-PDA combination Have implemented shared display, SVG, Text chat, Instant Messenger (using Jabber) 9/19/2018 uri="

PDA Collaboration Event Filter
Pass Through Shared Display GMS = JMS or Narada Lightweight Narada Hand Held Link Protocol 9/19/2018 uri="

Collaborative SVG 9/19/2018 uri="

Sharing Applications Very few applications are written as Web services Rather they integrate Rendering and Control These need to be separated for Easy Collaborative model Use on devices with limited rendering or for users requesting custom rendering Note important standards like W3C DOM do not separate “NaradaBrokering” Trap User Events Inject User Events Pre Web Service Shared Event Collaboration Control IE Word etc. Rendering 9/19/2018 uri="

Architecture of Collaborative SVG Application as a WebService
content server SVG Document Rendering Engine {JMS, NB} Client Controlling Event Session manager New/Updated Content SVG portlet Portlet A Portlet B Event Service {NaradaBrokering…} Chosen Rendering & Update Jetspeed Portlet Control Portlet Controller Turbine Screen Controlling Event New/Updated Content Setup HTTP request HTML content HTTP request HTML/WML content Controlling Event Communication Adaptor for PDAs New/Updated Content HHMS HTTP Client HTTP Client HHMS {JMS, NB} Client HHMS Client Minimum collaborative environment Minimum collaborative environment 9/19/2018 uri=" PDA user Desktop user

Select Collaborative SVG Portlet : HTML
for Desktop environment 9/19/2018 uri="

Collaborative content viewer for Users
Input URL of SVG document Browse Ready-to-use image from SVG content WS Catch user’s collaborative events from viewer 9/19/2018 uri="

Customized User-Facing Ports
User Profile Application or Content source WSDL Web Service F I U O R Render Portal (Aggregator) Selector Filter Control Channel Customized View Selection View (NaradaBrokering) Event Service Customized User-Facing Ports As used in Universal Access 9/19/2018 uri="

Different Models for Rendering
Current Collaborative SVG leaves Batik SVG browser largely unchanged but wrapped as a Web Service User sees a simple (say JPEG) rendering Very convenient for annotations etc. Alternatively take Batik source and split into two Control and Render/Catch User actions Build messaging interface between them and only wrap control Minimal Client Control Transform Transform DAT CTL CTL CTL DTX DTX DTX ….. ….. ….. DTX DTX DTX FPCL FPCL PPCL MCL DTX User Portlet Content Each of these is some sort of DOM All transformations must be “invertible” whether DOM “semantic” (Interpretable by CTL) or not (position of mouse click etc.) 9/19/2018 uri="

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