System Communication Architecture

System Communication Architecture

The System Communication Architecture (given as Systems Communication Architecture in some documents) is DEC's data networking architecture for VAXcluster systems; it defines the major constituent protocols, what functions each one performs, and how they interact. It allows the basic data-communication mechanism of a VAXcluster, the Computer Interconnect, to be shared between the numerous functions needed to operate the VAXcluster.

The System Communication Architecture has got a three-tier model consisting of the layers (from top to bottom):

• System Application (SYSAP), using the SYSAP Protocol
• System Communications Services (SCS), using the SCS Protocol
• Port/Port Driver Layer, using the PPD Protocol

SCA Services

The SCA architecture supports the performance of six different functions:

• Cluster configuration management
• Buffer management
• Connection management
• Directory services
• Datagram and sequenced- message services
• Named-buffer transfer services

See the article linked below for detailed descriptions of the SCA functions.

External links

• The System Communication Architecture, in DTJ, Vol. 1 No. 5, September, 1987 (pp. 24-30 of the PDF)