Messaging layer for network processors and coprocessors promotes interoperability
By Nicholas Cravotta -- EDN, January 8, 2004
The NPF (Network Processing Forum) has announced the availability of the Message Layer IA (implementation agreement). The spec standardizes communication among NPEs (network-processing elements), such as cryptographic engines, search engines, and other co-processor and processor components within a networking device. By defining the format and types of information that network-processing elements can exchange, the NPF hopes to move the industry away from proprietary message formats, thus simplifying and lowering the cost of integrating network-processing technologies from multiple vendors and enabling and promoting NPE interoperability.
The Message Layer sits at the boundary between the hardware interfaces over which it runs and the software APIs that run over it. The specification outlines a set of defined message fields from which an NPE can specify to capture the functions and data that a valid transaction requires, how to compose these message fields into valid messages, and a model for how an NPE can receive instantiation of message fields. Through such abstraction, developers can design networking software with little or no awareness of the hard details of the underlying hardware interfaces over which messages will travel. The spec combines this feature with a high degree of flexibility, enabling the reuse of software across hardware and software interfaces. Such reuse will enable third-party developers to develop and market hardware and software that serves the entire industry rather than a select subset of partner vendors.
The IA covers NPE-to-NPE communications over a range of common network-processing interfaces, including the NPF's Streaming Interface and Look Aside Interface, as well as various switch fabrics. All conveyances must meet a minimal set of the IA’s requirements. In-band messages comprise a configured number of fixed-sized, 1-byte slots in one or more consecutive message fields, which, in a message header or message trailer, carry the NPE-to-NPE information along with the message payload. An out-of-band configuration mechanism determines the meaning associated with the in-band messages for both the sending and the receiving NPEs. The Message Layer IA is available free from the NPF Web site at www.npforum.org/techinfo/approved.shtml.
Network Processing Forum, www.npforum.org.
