Presentation on theme: "Access Grid Update Robert Olson Argonne National Laboratory SURA/ViDe 5 th Annual Digital Video Workshop."— Presentation transcript:
Access Grid Update Robert Olson Argonne National Laboratory SURA/ViDe 5 th Annual Digital Video Workshop
Abstract In the years since we released the first Access Grid specifications and software, we have learned a great deal about how one might use this technology to enhance collaboration. With the 2.0 release of the AG software, we apply this knowledge to produce a system that is much more capable of enhancing collaboration between groups of people and the tools they use. In this talk I discuss what is new with the AG 2.0 software release and how its capabilities may be applied.
The Access Grid The Access Grid projects focus is to enable groups of people to interact with Grid resources and to use the Grid technology to support group to group collaboration at a distance Supporting distributed research collaborations Distributed Lectures and seminars Remote participation in design and development Virtual site visits and team meetings Complex distributed grid based applications Long term collaborative workflows
Access Grid – The Novel Ideas Peer-to-peer Virtual Venues servers to enable worldwide, secure virtual communities through the use of high-end collaboration environments Collaborative work sharing beyond simple application sharing Integration of high-end visualization environments into collaborative spaces Methods of asynchronous collaboration: capture, synchronization, record, playback and annotation of collaborative experiences.
HW Components of an AG Node Display Computer Video Capture Computer Audio Capture Computer Mixer Echo Canceller Network RGB Video NTSC Video Analog Audio Digital Video Digital Audio Shared App, Control Computer RS232 Serial
Access Grid Project Goals Enable Group-to-Group Interaction and Collaboration Connecting People and Teams via the Grid Improve the User Experience: Go Beyond Teleconferencing Provide a Sense of Presence Support Natural Interaction Modalities Use Quality but Affordable Digital IP Based Audio/video Leverage IP Open Source Tools Enable Complex Multisite Visual and Collaborative Experiences Integrate With High-end Visualization Environments ActiveMural, Powerwall, CAVE Family, Workbenches Build on Integrated Grid Services Architecture Develop New Tools Specifically Support Group Collaboration
Our Approach Attack Research Questions in the context of real world experience Build up a critical mass of groups using the AG Platform Involve multiple groups in trying new ideas and evaluation Build Working Infrastructure as well as Prototype Software Argonne has five working AG nodes under development New Software is used weekly/Daily as part of standard nanocruises Involve multiple groups in deployment, use and research Active collaborations with over a dozen groups working on AG technology Release software early and often (use open source model) Contribute to the Community Code base
Group-to-Group Interaction is Different Large-scale scientific and technical collaborations often involve multiple teams working together Group-to-group interactions are more complex than than individual-to-individual interactions The Access Grid project is aimed at exploring and supporting this more complex set of requirements and functions The Access Grid will integrate and leverage desktop tools as needed
Some Access Grid Active Research Issues Scalable wide area communication Evolution of multicast related techniques, and time shifting issues Scoping of resources and persistence Value of spatial metaphors, security models Virtual Venues, synchronous and asynchronous models Improving sense of presence and point of view Wide Field Video, Tiled Video, High-resolution video codecs Network monitoring and bandwidth management Beacons and network flow engine Role of Back-channel communications Text channels and private audio Recording and playback of multistream media
What is the Access Grid? Virtual Venues Places where users collaborate Network Services Advanced Middleware Virtual Venues Client User Software Nodes Shared Nodes Administratively scoped set of resources Resources Provide capabilities Personal Nodes User scoped set of Resources Users collaborate by sharing: Data Applications Resources
Access Grid Architecture
Virtual Venues What is a Virtual Venue? A Virtual Venue is a virtual space for people to collaborate What do Virtual Venues provide? Entry/Exit Authorization Information Connections to other Venues Coherence among Users Venue Environment, Users, Data Client Capabilities Negotiation List of Available Network Services Keep track of resulting Stream Configurations Applications Virtual Venues have two interfaces Administrative – Venue Management Software Client – Virtual Venue Client Software
Virtual Venues Client Enable face-to-face meeting activities What can be done: Sharing Data Shared Applications Applications: Distributed PowerPoint Shared Web browser Whiteboard Voting Tool Question & Answer Tool Shared Desktop Tool Integrate legacy single-user apps
Network Services Provide a middleware layer for enabling the richest collaborations Are invisible to Venues Clients, used by Virtual Venues Primarily Transform streaming data Can be anywhere on the network Can be composed to build complex solutions: Venue Audio Stream Audio Transcoder Audio to Text Two-Way Pager Two-Way Pager Text to Audio Audio Transcoder Venue Audio Stream Network Services provide opportunities for third party developers ANL is working on Network Services for Audio Transcoding (16KHz 8KHz) Video Stream Selection
Access Grid Nodes Comprise a set of collaboration resources Expose those resources through Node Services Basic Node Services include: Audio & Video Services Network Performance Monitoring Service Network Reliability/Fallback Service Leashing Service – Registering presence with a shared node Extended Node Services could be: Display Service with enhanced layout control Video Service supporting new CODECs Automatic performance adaptation Application Hosting Service
Access Grid 2.0 Design Requirements Secure Communication Throughout Reliable, Robust Data Transport Example: Network Failover Technology More Diverse Reference Platforms Handhelds High End Solutions Personal and Shared Nodes More Usable Software Well Documented Interfaces Federated Operation Integrate Grid Computing Technology AG 2.0 is Web Services based AG 2.0 uses GT2.X AG 2.0 can enhance an OGSI by providing collaboration services
Access Grid Nodes Access Grid 2.0 reference platforms: 1.Advanced Node – Tiled Display, Multiple Video Streams, Localized Audio 2.Room Node – Shared Display, Multiple Video Streams, Single Audio Stream (AG 1.x Node) 3.Desktop Node – Desktop Monitor, Multiple Video Streams, Single Audio Stream (AG 1.X PIG) 4.Laptop Node – Laptop Display, Single Video Stream, Single Audio Stream 5.Minimal Node – Compact Display, Single Video Stream, Single Audio Stream What Hardware? Cameras, Microphones, Speakers, Display, Input Devices Get Audio Correct! Software Requirements? Python 2.2, wxPython, GT2.0, pyGlobus
Summary of Changes from 1.0 to Virtual Venues Static Media Configurations Assumed Multicast Technology Single Server assumption Virtual Venues Client Web Browser Nodes Non-extensible single reference platform AG PIGs introduced Applications layered outside of AG software 2.0 Virtual Venues Dynamic Media Configurations Capability Brokering Functionality Integrated Data Storage Support for highly scalable deployments Multicast Addressing Topological Simplicity (connections as URLs) Virtual Venues Client Streamlined Client Integrated Grid Security Workspace Docking Application Development Interfaces Exposed Nodes Nodes defined in terms of resources Management UI Interfaces exposed for building new Services Broader set of Reference Platforms Applications Venue Hosted Collaborative Apps Network Services
Access Grid 2.0 Development Technology Details: Windows (2000, XP) Linux Globus Toolkit 2.X Web Services We prefer Python Partners Tools Globus toolkit Python CoG kit (LBNL) LBNL Intergroup Communications (LBNL) Condor ClassAds Project Strategy Open Source Project Model Standard Tools CVS, Bugzilla Access Grid Project Meetings First Tuesday of each month Argonne Institutional Venue Next meeting April. 1st, 2003, 10-12am CST.
Access Grid 2.0 Timeline Code Available now from: co AccessGrid 2.0 Beta 1 Available now (March 15, 2003) Virtual Venues Server Transitional Venue Server for AG1.X AG2.0 Migration https://vv2.mcs.anl.gov:9000/Venues/default (The Access Grid Lobby)https://vv2.mcs.anl.gov:9000/Venues/default Basic Node Services Virtual Venues Client Software Venues Management UI Final 2.0 Toolkit April 15 th, 2003
Access Grid Technology Overview
Technological Goals Enable comprehensive security Leverage existing technology Globus Toolkit SOAP + WSDL Provide a low barrier of entry for … New developers Rapid development of new functionality Adding third-party extensions
Security: General goals Identification of users and services Authentication of the identity of these users and services Authorization for access to resources Privacy of data (files, streams, control, etc.) Public Key Infrastructure provides standards and mechanisms to fulfill these needs
Security: Identification Users and services identified with a public key identity certificate issued by a trusted certificate authority An identity certificate contains: Information about the subject of the certificate A public key representing the subject The digital signature of the CA issuing the cert
For example, a Globus identity certificate: % openssl x509 -noout -text -in ~/.globus/usercert.pem Certificate: Data: Version: 3 (0x2) Serial Number: 6060 (0x17ac) Signature Algorithm: md5WithRSAEncryption Issuer: C=US, O=Globus, CN=Globus Certification Authority Validity Not Before: Jan 7 20:22: GMT Not After : Jan 7 20:22: GMT Subject: O=Grid, O=Globus, OU=mcs.anl.gov, CN=Bob Olson Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (1024 bit) Modulus (1024 bit): 00:cd:7d:bb:ae:30:bb:c1:74:2d:e4:6e:d4:30:6e: [etc] Exponent: (0x10001) X509v3 extensions: Netscape Cert Type: SSL Client, SSL Server Signature Algorithm: md5WithRSAEncryption 23:14:96:05:0d:db:ce:aa:70:17:03:5a:07:31:a0:81:e3:10: … Identity Certificates Subject information Subject Public Key CA Signature
Security: Authentication Assumptions: Authentication takes place on a transaction between a client and a server Client and server each hold an identity cert Authentication is mutual: After completion, client and server have verified identity of the other party Secured communications in AG2 use Globus… …which uses SSL/TLS SSL/TLS defines protocol for a secure handshake with mutual authentication.
Security: Authorization Authorization is the process of gating access to a resource based on some criteria. Many different approaches, few standards. Access control lists Role-based authorization Attribute certificates AG2 approach: provide building blocks for applications to define authorization. Reference implementation uses a basic role-based authorization scheme.
Security: Privacy Usually what people think when they think security Straightforward, once authentication and authorization issues overcome Globus Security Infrastructure uses SSL/TLS mechanisms for privacy Typically, symmetric encryption with session keys negotiated at session startup. Media data uses AES encryption with session keys distributed by secure channels.
Practical security issues In AG2.0 Alpha, each user must have an identity certificate Identity certs issued by Certificate Authorities AG Development CA Globus test CA DOE Science Grid CA Commercial CA (Verisign, Thawte, …) Certificate Safety If the private key for a cert is compromised, the cert cannot be trusted Hence, users have responsibility for maintaining safety of their keys The use of identity certificates is often cumbersome
Identity Maintenance Alternatives NCSA MyProxy Online proxy storage for standard identity certificates Medium-term expiration proxies kept at central server Proxies created via username/password authentication Online CA with username/password support Identity certificates held at an online CA Proxies created via username/password authentication No requirement for user storage of certs Integration with Shibboleth or other single sign-on infrastructure
Trust issues If a CA is not trusted by a service, then no certificates issued by that CA are trusted CA trust is a minimum requirement for access
Building on Access Grid 2.0 The Access Grid Toolkit is extensible by the addition of Node Services, Network Services and Applications. This tutorial covers the building of a Node Service and the building of two Applications: A Shared Web Browser A Distributed Presentation Viewer
Building a Node Service Node Services for Streaming Media Responsibilities Adhere to Node Service interface Packetize and send media streams to network Respond to stream description updates
Building Applications Applications rely the Venue for discovery, coherence, coordination and synchronization. In order to support Applications, we have added a new piece an Application Factory to the Venue. Application Factory Application Objects + Application Clients Distributed Applications integrated with AG
Application Architecture: Venue Side An Application Factory creates Venue-resident applications. Each application is represented in the venue by an Application Object An application object can store local data and can have one event channel Event channels utilize a Venue-based Event Service Venue Event Service Application Object name type webServiceUri channel Event Channel Local Data Application Factory
Venue Application Architecture: User Side On the user side the Venue Client is the key. The user can install applications, which are then available to the Venue Client. When a user enters a Venue if there are application objects, the Venue Client looks for applications that are of the same type. The Venue Client also enables the user to start a local application, and create the Application Object in the Venue. Venue Client Application Client Type: X Application Client Type: Y Application Client Type: Z Venue State (Including Application Objects)
Example Applications Shared Web Browser Stateless – Current page not stored anywhere but in the clients Shared Presentation Viewer Stateful – Master Presenter Current Slide Slides
A Shared Web Browser Application task: Web browsing All users see the same page The Venue serves as a rendezvous mechanism Application state: webpage URL State is distributed; that is, there is no central server maintaining the state With each state change, an event is distributed to all interested clients
Distributed Presentation Application task: coordinated display of presentation material PowerPoint is the prevalent client, but the application can be built in a platform independent way. Application state A presentation (set of slides / images / pages) Current location within the presentation A presenter who has control of progress through the presentation
Access Grid Overview of Core Venue Server Management Nodes and Node Management Network Services Plans for the next year
Venue Server Management
Administrators Multicast address allocation Standard range Custom range Storage Location
Venue Server Management Support for static addressing Transitional venue server Network address requirements, like SCGlobal Add/Remove Exits
Nodes and Node Management An AG Node often consists of multiple machines The central NodeService communicates with a ServiceManager on each machine
Nodes and Node Management Users install available services to establish the capabilities of the Node Adding services extends the collaborative capabilities of the Node Services are simple to develop and integrate, facilitating third-party development
Nodes and Node Management The structure of an AG2 Node is more flexible than AG1 Nodes. On a personal Node, all the services would run on a single machine.
Nodes and Node Management Node Services Expose resources on the machines in the node Implement a specific network interface Provide capabilities to the node Video, h261, 25fps Audio, 16kHz
Nodes and Node Management Node Management UI Add Service Managers Add Services Configure Services Store/Load Configuration
Nodes and Node Management Where AG1 Nodes consist of a collection of hardware in a single, static configuration, AG2 enables multiple configurations: One stream for a presentation (e.g. an instructor) Multiple streams for a group attending a presentation (e.g. a classroom) High-bandwidth/Low-bandwidth configurations
Node/VenueClient/Venue interaction A users enter the Venue with the collected capabilities of his node If the user has the capability of producing a media stream not present in the Venue, the Venue allocates a new stream Streams are present in the Venue as long as participants are providing that stream to the Venue; the addresses assigned for media transmission are allocated and freed dynamically
Network Services Users with incompatible capability sets could be in a venue together, but would be unable to interact The Venue could resolve these incompatibilities with appropriate adapters, through Capabilities Negotiation Video, h261 => Video, jpeg Audio, 16kHz => Audio, 8kHz We call these adapters Network Services
Plans for the next Year OGSI and GT3 Multiple certificates / Graduated security / Authorization ?? Graduated security == Roles? ?? Authorization Building communities with the AGTk (~VO) ?? Community authorization server
Plans for the next Year Venue Client Client-side datastore/Docking Subgroup communications Automatic bridging
Plans for the next Year Nodes Node advertisement Node Services ? High-res Video ? Stereo Audio Display Service supporting advanced layout Camera Control Service Operator Panel Consolidate as much of the hands-on operational functionality of existing media tools in a single, compact interface
Plans for the next year Venues and Venue Server Capabilities Negotiation Venue Server Registry Stream Selection