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- Submitted-by: pc@hillside.co.uk (Peter Collinson)
-
- USENIX Standards Watchdog Committee
- Stephen R. Walli <stephe@usenix.org>, Report Editor
- Report on 1003.12: Protocol Independent Interfaces
-
- Mike Karels <karels@cs.berkeley.edu> reports on the April
- 15-19, 1991 meeting in Chicago, IL:
-
- Summary
-
- The POSIX.12 (Protocol Independent Interfaces, PII) working group
- spent the April meeting planning strategy for its new direction and
- coordinating with other groups. The group will produce a standard
- encompassing both the BSD sockets and X/Open Transport Interface
- (XTI). Liasison meetings were held with X/Open representatives, the
- Name Space/Directory Services group (POSIX.17) and the Real-Time group
- (POSIX.4). The group discussed language independent specification
- issues with Paul Rabin.
-
- Report
-
- POSIX.12 (Protocol Independent Interfaces, PII) spent the April
- meeting adjusting to its new direction and coordinating with other
- groups. At the last meeting, the group decided to abandon its
- previous strategy of producing a new Detailed Network Interface (DNI)
- with the best features of both the socket and X/Open Transport
- interfaces (XTI). XTI is derived from AT&T's Transport Level Interface
- (TLI). After reviewing input from users and vendors, the group
- decided instead to produce a standard including both existing
- interfaces. In addition, the standard will include the Simple Network
- Interface (SNI), which would insulate the programmer from lower-level
- details.
-
- The April meeting included discussions of the changes or additions
- that were needed for the existing interfaces to become standards. A
- poll had been sent to several mailing lists and news groups, but few
- concrete suggestions were received. Most of the suggestions for
- extensions have come from inside the working group. Suggestions for
- changes in sockets have come mostly from the Berkeley representatives,
- and suggestions for XTI have come mainly from people active in the
- X/Open technical community.
-
- A fair amount of time was devoted to the proposal for extending XTI
- option management by Gerhard Kieselmann. The proposal allows much
- more flexible option management by encoding option values with types
- and lengths. The encoding is similar to the encoding of ancillary
- data in the 4.3-Reno send and receive calls. The main point of
- contention was whether the transport provider should maintain both
- current settings and default settings to be used for any future
- connections.
-
- The discussions of extensions to the socket interface was confined to
- a description of the recent Berkeley changes (4.3-Reno) to the socket
- interface.
-
- The meeting schedule was nearly filled with coordination meetings with
- other groups. Petr Janacek of X/Open reported on the status of future
- XTI specifications. Other than the option management proposal
- mentioned above, the XPG4 version of XTI has been finalized. It is
- hoped that the XPG5 version of XTI would be aligned with the POSIX
- version. At the last meeting, POSIX.12 asked X/Open for editorial
- assistance in producing a POSIX version of XTI. Petr replied that the
- budget did not allow for assistance at this time, but that an on-line
- version of XTI would be made available.
-
- Paul Rabin met with the PII group to discuss issues surrounding POSIX
- language independent specifications. The working group currently
- hopes to produce a single language independent specification for DNI;
- there would be two C language bindings, namely sockets and XTI. This
- should prevent the necessity of providing two interfaces for languages
- other than C, but makes the language independent specification more
- difficult to produce.
-
- The POSIX.12 group also met with members of the Name Space/Directory
- Services group (POSIX.17) to discuss the DNI dependency on the
- Directory Services interfaces. There are some problems in this area;
- the NS/DS group currently intends to provide an interface only to the
- X.500 directory service, while the PII group assumes an interface that
- could include other services such as the Internet Domain Name System.
- The NS/DS group intends to provide a full-featured low-level interface
- to the directory service based on the X/Open X.500 API. However, they
- also plan to include simplified higher-level interfaces to answer
- needs such as this one.
-
- The final coordination meetings were with members of the Real-Time
- group. The current Real-Time draft includes an interprocess
- communication (IPC) facility that many believe is too complex and does
- not extend gracefully to handle networked systems. Many hoped that
- the IPC interface could be replaced by the 1003.12 interface, with
- real-time extensions as necessary. A group is working on a straw-man
- proposal in time for the July meeting.
-
-
- Volume-Number: Volume 24, Number 26
-
-