Transcript Web Services Discovery and - Events

Web Services Discovery and
Web Services Devices Profile
Toby Nixon
Co-Chair, OASIS WS-DD TC
[email protected]
Networked Device Standards
“The Great Thing about Standards is…
… there are so many to choose from!”
2
Industry Challenges
• Non-interoperable or gateways required
– And often gateways not available
•
•
•
•
•
Proprietary physical interfaces
Tied to single physical layers
Non-standard link protocols
Platform- or runtime-specific
Not extendable
– Limited opportunity for innovation
• Not scalable
• Limited, if any, development tools
• Security
3
Web Services
• Interoperable machine-to-machine interaction
over a network
– Programmatic interfaces
• Messages formatted using XML (Extensible
Markup Language)
• Simple Object Access Protocol (SOAP)
• Web Services Description Language (WSDL)
4
Benefits of Web Services
•
•
•
•
•
•
•
•
•
•
5
Work on any physical network
Standard protocols: TCP/UDP/IP, HTTP, XML
Not platform- or runtime-specific
Scalable from smallest device to the internet
Extendable by vendors and orgs
Excellent development tools from many
vendors, and many trained developers
Secure
High performance
Many infrastructure components available
Leverage industry investments
UPnP – 1st Generation
• Rolled out in 1999 – UPnP Forum created
– 10th Anniversary is this fall
• Web services were in their infancy
– HTTP, XML, SOAP… not much else
– UPnP is based on an early snapshot
• But many benefits from just these basics, so
industry moved ahead with UPnP adoption
– Most adoption for NAT traversal and media sharing
– UPnP supported in Windows since Windows ME
6
UPnP Status
• UPnP Forum now has over 880 members
– UPnP Forum was incorporated in January, 2009
• 72 UPnP specifications were published as
ISO/IEC standards in December, 2008
– UPnP Device Architecture 1.0
– DCPs: Basic Device, AVv1, AVv2, Digital Security Camera,
HVAC, Lighting, Internet Gateway, Printer, Scanner, QOSv1,
QOSv2, RemoteUI, Device Security
• New specifications not yet submitted to ISO/IEC
– Done: UDA 1.1, Low Power, AVv3 and QOSv3
– Work in Progress: Remote Access, Content Sync, Device
Management, Telephony, AVv4
7
DPWS – 2nd Generation
• UPnP 2.0 was proposed in 2002
– Full alignment with Web Services architecture
– Lightweight profile of Web Services specifications
appropriate for embedded device applications
– Work suspended because some specs not ready,
including Discovery and Eventing
• Work started on Devices Profile for Web
Services, WS-Discovery, and WS-Eventing
– BEA, Canon, Computer Associates, IBM, Intel,
Lexmark, Microsoft, Ricoh, SoftwareAG, and TIBCO
worked on various components
– Industry workshops and plugfests
– DPWS first published in 2004
8
How It Works
•
•
•
•
•
•
•
9
Addressing – automatic assignment
Discovery – automatically find devices
Description – what can the device do?
Control – invoke device functions
Eventing – monitor device state
Presentation – use device’s web interface
Security – authentication, integrity, privacy
Addressing
• Address assignment not detailed in DPWS
– But typical implementations all work the same way
• IPv4
– Attempt DHCP address assignment
– If fails, use “Auto-IP” (RFC 3927) self-assigned local
address (169.254/16)
– Check periodically for DHCP server
– Static IP addresses also permitted
• IPv6
– Obtain address from DHCP or Router
– Or use self-assigned Unique Local Address (RFC 4193)
10
Discovery
• WS-Discovery
– Being standardized in OASIS WS-DD along with DPWS
• Device multicasts “Hello” when joins network
• Client requests address using “Resolve”
– Device responds using “ResolveMatch”
• Clients can search using multicast “Probe”
– Devices respond using “ProbeMatch”
• Device multicasts “Bye” when leaving
• WS-Discovery also defines “discovery proxy”
server role for managed networks, scalability
11
Description
• Client uses WS-Transfer to Get device
description information
– ThisModel: e.g. manufacturer name, model number
– ThisDevice: user-assigned name, serial number,
firmware version
– Relationship: List of device types and services
available on device, and their WS-Addressing EPRs
• Client can use WS-MetadataExchange
GetMetadata to download WSDLs for services
– Data types, Port types, Operations, Messages
– Used more at development time rather than run time
12
Control
• Actions defined in the service WSDL are
invoked using SOAP over HTTP
• Responses returned using SOAP over HTTP
13
Eventing
• WS-Eventing
– Being standardized in W3C WS-ResourceAccess WG
• Clients Subscribe to event notifications
– Address to deliver events
– Desired duration of subscription
– Optional filter expressing events of interest
• Service sends SOAP messages to client to
deliver event notifications
• Client can Renew subscription, or Unsubscribe
• Service can send SubscriptionEnd to
terminate subscription before expiration
14
Presentation
• Enables web interface to device
• PresentationURL is included in ThisModel
metadata element
• Client uses browser (HTTP GET) to use device’s
web interface
• Metadata also includes
– ManufacturerURL
– ModelURL
15
Security
• Optional
• Secure devices must have X.509v3 certificate
– Should be unique for each device instance
• Based on SSL/TLS (https://)
– Establish secure channel for description, control, and
eventing for authentication, integrity, and
confidentiality
– Device can require either X.509 certification or
username/password authentication of client
• Multicast WS-Discovery messages
authenticated and integrity-checked using
Compact XML Signatures
16
UPnP – DPWS Comparison
UPnP
DPWS
Addressing
DHCP, AutoIP
Not Defined
Discovery
SSDP
WS-Discovery
Description
UDA Schema
WSDL
Control
SOAP 0.9, 1.1
SOAP 1.2
Eventing
GENA
WS-Eventing
Presentation
HTTP, HTML
HTTP, HTML
17
DPWS – Subset of WS-* Suite
Non-DPWS
WS-Federation
WS-Management
Workshop Member Sub Submitted
Devices
Profile
WS-Discovery
UDDI
WS-Atomic
Transaction
WS-Trust
WS-Security
WS-Reliable
Messaging
WS-Coordination
WS-Transfer
WS-Enumeration
WS-Eventing
SOAP
WS-Addressing
MTOM
XML Infoset
18
Metadata
Assurances
WS-Secure
Conversation
XML 1.0
Infrastructure
and Profiles
Standard
WS-Metadata
Exchange
WS-Policy
Messaging
XML Schema
SOAP / UDP
XML
Namespaces
MIME
WSDL
SOAP / HTTP
Foundation
DPWS Standardization
• OASIS WS-DD TC
– Web Services Discovery and Web Services Devices
Profile Technical Committee
– http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-dd
– Co-proposed by CA, Canon, Lexmark, Microsoft,
Nortel, Novell, Progress Software, Red Hat, Ricoh,
Schneider Electric, Software AG, and WSO2
• DPWS, WS-Discovery, and SOAP-over-UDP
– Not any specific device classes
•
•
•
•
19
First Meeting September, 2008 in Redmond
Quarterly face-to-face meetings, weekly calls
Original Goal: Completion by 2nd quarter 2009
OASIS Final Approval vote is June 16-30, 2009
DPWS Standardization
• WS-DD Charter Clarified May 7, 2009
– TC will continue in maintenance mode until closed
– Update DPWS to refer to W3C Recommendation
versions of WS-Eventing, WS-Transfer, and WSMetadataExchange; profile as necessary
– Update to WS-I Basic Profile 2.0 if available
– Deferred issues, spec issues, errata
– Further work on Security if needed
– DPWS 1.2 completion dependent on completion of
work in W3C WS-ResourceAccess WG
20
DPWS Stacks
• Microsoft
– Windows Vista and Windows 7
• Printers, Scanners, Conference room projectors
• Discovery of computers and users
–
–
–
–
Windows Embedded CE 6.0 R2
Windows XP Embedded
.net Micro Framework 3.0
Biztalk Server 2008
• RFID readers
• Other stacks
– Levitate, Peerless, SOA4D, gSOAP, eSOL, DotVision,
DPWS4J
21
DPWS Implementations
• Printers and Scanners
– Canon, HP, Xerox, Epson, Lexmark, Brother, KonicaMinolta, Fuji-Xerox, Toshiba, Ricoh, others
• Projectors
– Epson, NEC, Toshiba
– Several others coming
• Industrial and home control
– Schneider, Hager, LeGrand, Beckhoff, Vantage
– Exceptional Innovation
• Audio, Video, home control, hotel control
• Over 1000 deployments in USA
– Disney Home of Tomorrow
• Thousands of devices, 50K visitors in first week
22
Future DPWS Applications
•
•
•
•
•
•
•
•
•
23
Point of Service
Energy Management
Network Infrastructure
Healthcare
Hospitality
Factory Automation
Mobile devices
Automotive
Many more…
What About Device Schemas?
• OASIS WS-DD will not define device class
specifications/schemas – outside of scope
• No SIG or other organization for DPWS
– Nothing like UPnP Forum for DPWS
– No DPWS-specific certification or logo program
• Individual device classes might have them
• Any organization can reference DPWS
– Device schema specifications should be prepared in
the most appropriate existing industry organization
– OASIS would be a great home for a device class when
no other organization takes ownership
• Your organization can start today!
24
Thanks!
Questions?
25