Browse Prior Art Database

Improved Test Procedure in Transmission Networks

IP.com Disclosure Number: IPCOM000048205D
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Related People

Cholat-Namy, J: AUTHOR [+2]

Abstract

Status control in a transmission network requires means for propagating a status request generated on a channel (A,B,C or D) which might be attached to a host unit, down to the specific network element the status information of which is desired. and then getting that information back. This may be performed by stopping, meanwhile, any data communication or by providing the network system with a service channel separate from the data channel.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Improved Test Procedure in Transmission Networks

Status control in a transmission network requires means for propagating a status request generated on a channel (A,B,C or D) which might be attached to a host unit, down to the specific network element the status information of which is desired. and then getting that information back. This may be performed by stopping, meanwhile, any data communication or by providing the network system with a service channel separate from the data channel.

Both of these approaches present obvious drawbacks. Accordingly, a system and/or process for providing supervisory information exchange within the network without additional channels and without data transmission interruption would be most welcome.

The figure shows a two-level network. The first level network includes a host station and a slave station, with the stations being connected together through a full duplex line. The host and slave are both provided with a channel multiplex (MPX) card and a modem (M1, M2). The second level network comprises tail units attached to the slave. Each modem is provided with a Test Unit permanently scanning transmit and receive channels to detect any test request. Let us assume that channel B requires a status delivery. Its RTS (Request To Send) line (see CCITT Recommendation V24) being ON, the DTE (Data Transmission Equipment) attached to channel B sends SDLC (Synchronous Data Link Control) flag "7E" followed by a specific message announcing a test type of command and then by the specific test (status) command If the required test does not involve the attached modem (host modem), i.e., local status is requested, no setting of the modem in test mode is necessary. The Test Unit thus transfers the status onto the receive data line of channel B. However, if the test request relate...