More web services specs on the way

IBM, Microsoft, BEA and Tibco have published two new web services specifications aimed at improving interoperation between systems.

But the arrival of more web services standards is causing analysts to question whether the technology will eventually become too complicated, thereby undermining its appeal.

The new specifications are called WS-ReliableMessaging and WS-Addressing.

The first provides a protocol for ensuring that unreceived and duplicated messages are detected, and received messages are processed in the order in which they were sent.

Different levels of delivery assurance can be offered using the protocol: deliver at least once, at most once, precisely once, and in order.

WS-Addressing is used to identify and exchange logical references to physical message delivery end points, and includes a set of commonly used message information headers.

"The original goal of Simple Object Access Protocol was a simple mechanism for invoking processes on a remote machine," Gary Barnett, principal consultant at analyst Ovum, told vnunet.com.

"The concern I have is that every time people get together to create a new standard, do they ask: 'Is the benefit going to outweigh the additional complexity to web services?'"

Barnett added that the complexity built into the Common Object Request Broker Architecture (Corba) interoperability standard undermined its take-up. As a result, only the basic Corba layers are now being used.

The analyst suggested that the two new standards were needed because the different companies' proprietary message oriented middleware could not be relied on to work together.

Implementing the two specifications should mean that multiple messages are handled asynchronously across firewalls and gateways independently of the underlying messaging system.

The overall architecture takes into account the previously announced WS-Policy and WS-Security specifications.

But the white paper also identifies other messaging requirements, such as flow control and metadata exchange, that still need addressing.