ESMI-032-R1

• 1. TF-34 and Web Services Presented at ESIF-11 Task Force 34 October 26, 2004 John Sines [email_address]

2. What is a Web Service?

• A Web Service is

• A web service is a software application identified by a URI, whose interface and bindings are capable of being identified, described and discovered by XML artifacts and supports direct interactions with other software application using XML based messages via Internet-based protocols.

• (World Wide Web Consortium)

3. Intent of Web Services

• A language and platform independent method to implement Service Oriented Architecture (SOA) using standard internet technologies

• For application-to-application communication

• Has little to do with HTML

• Not limited to someone adding a hook into their web site. A web service can live anywhere on the network (Inter or Intra).

• Entities choose to use web services for ease of implementation, conciseness of the standard, and low cost

4. Examples of Web Services

• Southwest Airlines accesses Budget Rent-a-Car to make car reservations after making airline reservations

• Amazon allows other companies to search and purchase items via Web Services. If you are a nutritionist you can purchase nutrition books from Amazon without leaving your nutrition web site

• There are stock-quote services, traffic-report services, and a weather services available

• Ideal for any Service Oriented Architecture (SOA) deployment

5. What makes up a Web Service

• All components are based on theXMLstandard

• • SOAP:Simple Object Access Protocol

• • WSDL:Web Service Description Language

• • UDDI:Universal Description, Discovery, Integration

6. SOAP

• SOAP is the service messaging layer of a web service. The messages are XML based.

• The protocol consists of three parts:

• An envelope that defines a framework for describing what is in a message and how to process it

• A set of encoding rules for expressing instances of application-defined datatypes

• A convention for representing remote procedure calls and responses

• A transport or protocol binding

7. WSDL

• A WSDL is an XML document that describes the functional characteristics of the services offered.

• The WSDL describes:

• The operations the service has available

• The messages the service will accept

• The protocol of the service

8. Where Web Services exist in the Standards World

• W3C

• • XML Specifications

• • WSDL Definition Specifications

• • SOAP Specifications

• • UDDI Specifications

• • Web Services Architecture and Interoperability (WS-I) Profiles

• Maturity of Standard

• • Introduced in 2000, and gaining momentum. Many companies are in 2 ndand 3 rdgeneration deployments

• • De-facto Standard for SOA over XML

• • Who uses them?

• • • Anyone who needs interoperability between applications

• Software and Hardware industry giants such as IBM, Sun, Dell, Microsoft, Intel are behind the standard

9. Why Web Services for ESNet?

• Can be done in a faster and cheaper manner

• • WSDL gives widely recognized definition language to define the service messages between the GWs and the CSCEs

• Platform and Technology neutral

• Insulates TF-34 from the intricate underlying details of defining a protocol

• Ease of adding new services

• ComCARE messages are being defined as web services

• NENA 4 Generation 1 has already developed schemas for the ALI Type Lib. The schemas are 2 weeks away from final approval

• http://www.nena.org/xml%5Fschemas/Current%20Release/Version%204.X.X.list.html

10. Reliability

• Reliability is a concern

• Leverage existing technologies such Clustering and Load Balancing to transparently manage reliability

• Techniques have been established to ensure that the messages get to their endpoints

• Heartbeat mechanism can still be implemented

11. Security

• Security concerns are the same as connection oriented architecture

• Web Service over HTTP or HTTPS can be as secure as any website

• • SSL, Basic Auth, NTLM, Passport, custom

• Relies on security capabilities of the transport layer

• Security best practices are being recommended. People who specialize have put an a great amount of effort in developing the best practices documents.

12. Pros and Cons of Web services for ESNet

• Pros

• • Faster definition and deployment. Reduced deployment cost for PSAPs, service providers, and ESMI intergrades

• • Clarity of the Standard

• • Ease of implementation with off the shelf technologies

• • • Can use Microsofts .NET or Javas J2EE (IBM Web Spear, BEA Web Logic, etc.)

• • • Leverage Application Server Technology

• • • Leverage Load Balancer Technology

• • A number of runtime management and support tools available

• • A number of production/development tools available (many more than SIP). In the .NET development environment, development of web services is completely wizard driven

• • Allows for extensibility in protocol

• • Allows for a more scalable architecture

• • Seamless fail-over with the use of Load Balancers and Clustering- Connections are acquiesced on every call to a service

• • Leverage existing NENA XML schemas

• • Ease of integration of ComCARE work

• • Allows for easy market entryfor new data service providers

• • Affords PSAPs highest degree of flexibility for adding new services

• • Supports distributed Service Registry's which dynamically show which services are available for use

13. Pros and Cons of Web services for ESNet (Continued)

• Pros (Contd)

• • SOA supports the creation ofSecurity Services which incorporates authentication, certification, andencryption through std.PKI and other security practices

• • Supports 'Virtual Security Gateways' which model a physical security gateway, but are more flexible to extend, consolidate, and upgrade

• • Each endpoint can be both a 'Client' and a 'Server' - this allows PSAPs to not only ask for information, but to also provide information easily

• • Web-Services can be added as extensions to existing hub-and-spoke system design toenable service-enabled applications to interoperate

• • Connectionless model only connects when datais needed - allows for messaging efficiency

• • Overall message overhead is reduced

• • Presence services can be implemented to ensure the application is available when needed (Heartbeats can still be implemented)

• • Web-based connectionsare fast - since these areno different thanany otherIP-based connection (on the order of milliseconds)

• Cons

• • The web services standards may evolve

• • Overhead in initiating a connection

• • Matching requirements - individual customer requirements are possible but need to be carefully managed among all customers

• • Availability - no architecture is perfect - many of the same dedicated 'guaranteed' data delivery infrastructure can be leveraged to assure increased availability in a Web-Services model

14. Pros and Cons of Hub and Spoke/Connection Oriented Architecture

• Pros

• • Few connection establishments means less overhead

• • Software exception is thrown if there is a problem with a TCP/IP socket

• • Hub-and-spoke Enterprise Integration Architecture(EAI) is the most popular of traditional EAI models - been around for a while

• • Hub-and-spoke EAI's provide physical congestion control points to the PSAPs

• • Hub-and-spoke EAI's provide physical congestion control points to the PSAPs

• • Affords CESE client a certain amount of autonomy by virtue of RG hiding rem