TF-34 and Web Services Presented at ESIF-11 Task Force 34 October 26, 2004 John Sines

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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)

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 5 What makes up a Web Service All components are based on the XML standard –SOAP: Simple Object Access Protocol –WSDL: Web Service Description Language –UDDI: Universal Description, Discovery, Integration

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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 nd and 3 rd generation 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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 04.X.X.list.html 04.X.X.list.html

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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.

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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 Microsoft’s.NET or Java’s 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 entry for 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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 13 Pros and Cons of Web services for ESNet (Continued) Pros (Cont’d) –SOA supports the creation of Security Services which incorporates authentication, certification, and encryption 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 to enable service-enabled applications to interoperate –Connectionless model only connects when data is 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 connections are fast - since these are no different than any other IP-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

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 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 –Affords CESE client a certain amount of autonomy by virtue of RG hiding remote data services –Allows for more responsibility to be placed on the hub provider for message content, integrity, and performance Cons –Complexity involved in defining the message set –Complexity involved in implementing the message set –Hub-and-spoke EAI's are built using proprietary 'middleware', as opposed to 'open' s/w standards and protocols –Message hub is centrally located by design, rather than distributed by nature –Introduces risk due to potential for central point of failure for a large number of automated processes (consider several hundred CESE's to one RG)

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 15 Pros and Cons of Hub and Spoke/Connection Oriented Architecture (Continued) Cons (Cont’d) –Uses persistent TCP/IP connections which would require frequent teardown and re-establishment (ref. TML initiative from T1 & OBF ATIS committees) –Dedicated circuits required - since Internet is a 'non-production' (inherently unreliable) for persistent connections –Number of dedicated circuits between each CESE and RG endpoint (~7,000 PSAPs = lot of circuits) –PSAPs must then support two circuit types for IP connectivity, dedicated and Internet-routed –A CESE is defined as a 'Client' only - though messages are defined to be intiated both directions, this complicates the connection methodology –Requirements for persistent connections and continuous heartbeats, puts greater load on systems and networks over that of a system that messages when it needs to –Proprietary message exchange implementations, such as TF34 is proposing, requires specialized programming knowledge and effort to develop, maintain, and upgrade –Introduces a TF34 'specific' messaging product between all available integrated applications

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 16 Problems with doing Connection Oriented Protocol in Parallel Longer standards development time The technologies are very different No good migration path from one to the other –Hardware as well as software required would be much different

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 17 Bi-directional Web Service

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 18 Possible Network Implementation

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 19 What a Solution Could Look Like

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 20 How to move Forward Define a WSDL that includes all of the messages –Map messages to WSDL

© HBF Group, Inc. 2004For ESIF Task Force 34 Use Only Page 21 Taken a step further, the entire ESNET could be a Web Service based peer network PSAP 1 (CESE 1 ) PSAP n (CESE n ) Service 1 Service n This would allow CPE vendors to supply services as PSAP demand dictates – all using the same mechanism of discovery and invocation. ALI, ACN, VoIP, etc. all become an accessible service. PSAPs share information on a peer basis.