eSangam is the second phase of National Service Delivery Gateway which supported integration amongst diverse set of applications built on varying platforms through compliance with below set of e-Governance Specifications based on open standards such as the W3C XML and SOAP specifications :
eSangam now supports Multiple communication protocols in addition to IIP/IIS Standards for message exchange. The rationale behind upgrading NSDG to eSangam was to minimize the overhead for departments getting integrated with eSangam by means of providing support for multiple protocols and to strip down the IIP/IIS specific header information required by gateway for a lightweight message structure. IIP/IIS Standards and Non IIP/IIS message standards are discussed below:
E-Governance infrastructure is necessarily a distributed one and there are a multitude of participants to this infrastructure. The communication between some of the key participants is critical to hold this infrastructure together need to be specified and standardized. The objective of Interoperability Interface Protocol (IIP) and Interoperability Interface Specification (IIS) is to standardize on the protocol and to specify the interface nature for this communication to take place.
IIP is the communication protocol that the Service Access Providers, e-Governance Gateway and the Service Providers need to comply with. This protocol is divided into two parts, one part targeted towards the Service Access Providers and one for the Service Providers. e-Governance Gateway as the infrastructure needs to support both the interfaces.
IIP is an asynchronous request-poll-retrieval protocol, with provisions for synchronous communication, which supports requests to be sent and receive a response through a polling mechanism or synchronously. The foundation of the protocol is based on message types and context based processing of messages. There are mechanisms for sending a request, communicating acknowledgements, querying the state of a request, sending and communicating responses and to handle error situations. The message types supported by this protocol are listed below :
Exchange of IIP compliant messages is intended to be the primary mode of communication between the Service Access Providers and the e-Governance Gateway as well as between the Service Providers and e-Governance Gateway. It is to be noted above that not all messages are required to be supported by the Service Access Providers and the Service Providers. Some of the above messages are mandated to be supported by the Service Access Providers and some for the Service Providers.
IIP provides the interoperable interface for communication and all the IIP messages are XML based, therefore readily usable by any application. This interface is the key for success of e-Governance Gateway.
IIP provides the protocol, the message formats and the associated semantics of the messages. However, it does not address the issues of the precise exchange of this information through a technology interface. Interoperable Interface Specification (IIS) address this issue. IIS provides the technological specification for exchanging of the IIP compliant message. To this end IIS provides the following :
IIS compliments IIP by translating the message exchange into a viable form of messaging mechanism, such that optimization can be achieved by the implementing application. In terms of carrier protocol, IIS follows SOAP, as standardized by W3C, such that wide industry support is available in forms of ready libraries and implementations. IIS is always used in conjunction with IIP; therefore it is uniformly applicable to the Service Access Providers, Service Providers and e-Governance Gateway.
The e-Governance Gateway infrastructure under various administrations in India will form a hierarchical constellation of which every state and centre Gateway will be a part. However, for this constellation to be realized and successfully operational there needs to be a set of predefined guidelines and standards, which will govern various aspects of the constellation, such as its structure, behavior and policy. The IOI Gateway Interconnect Specification (IGIS) is targeted towards providing such a comprehensive documentation of all aspects of the Gateway Constellation. The primary aim of this standard is to provide the specifications and protocols required for construction of the Gateway Constellation. In this endeavor, the document provides specifications at the following levels :
This specification defines the structure of the Gateway Constellation, the communication mechanisms between various gateways in the constellation, facilities to propagate a service request to its required destination and the policy guidelines applicable to each of the participating gateways in the constellation and the constellation as a whole. This specification is intended to provide the basis on which the Gateway Constellation will be realized. The specification and its associated protocol (s) may be realized with the help any suitable technology and means. In effect, this specification is a technology neutral specification, guideline and protocol enumeration for the Gateway Constellation.
Conformance to IGIS is required by any Gateway that needs to be a part of the Gateway Constellation and is therefore mandated for all state level and centre level Gateways.
These specifications are a compilation of a common set of services for eSangam Gateway. These services are considered generic enough in nature, such that they required by more than one government department and Service Access Providers. The generic nature of the services warrant their existence at eSangam Gateway Level, such that substantial reuse of these services can be achieved and individual applications in the eGovernance space of India (present and future) can are spared, metaphorically, the reinvention of the wheel. The set of service specifications contained in this document is expected to expand over time as and when new generic services are integrated into the eGovernance framework of India, therefore, this document intends to serve as the single and authentic source for all such service specifications and undoubtedly a living document, which shall witness many updates and augmentations.
The latest version of eSangam provides support to most of other protocols i.e. HTTP, SOAP, REST etc in addition to IIP/IIS Standards. The message types supported by these protocols are listed below:
As stated above, eSangam provides support for multiple protocols and provides protocol transformations for communication among applications supporting heterogeneous protocols. However, in order to ascertain the validity of the messages, the messages sent to eSangam must follow a minimal document structure. ESangam gateway will accept the messages in either SOAP or REST protocols over XML or JSON formats and the expected documents structures will be:JSON :