tracy@ihuxl.UUCP (Kim) (08/12/85)
I am looking for particulars on IBM communications configurations. Specifically, transmission rates and performance issues. Some of the questions I have are: 1) What are the maximum data rates between a channel attached cluster controller and a 327x type terminal? Does this rate depend on whether the cluster controller is on a 3MB/s or a 1.25MB/s channel? 2) Are the data rates between the cluster controller(CC) and the mainframe and between the CC and the terminals bisyncronous or asyncronous? The data rate between the terminals and the CC is usually quoted as ~2.3Mb/s. Does this sound right as a maximum rate? 3) Assuming that the data rate between the CC and the terminals is on the order of 2.3Mb/s, what does the data rate turn out to be when there are a bunch of terminal sharing the resources of the CC? 4) Performance data of any sort would be helpful. Such as: How dependent is the response time on the apparent data rate that users see (the degraded 2.3Mb/s)? How does the apparent data rate vary with differing configurations(remote CC, mix of terminals/printers, fullness of controller, etc...)? Does anyone determine what the apparent data rate is? (please note that I am defining apparent data rate as the rate that users see, that is, if they had a line that did not depend on the CC, they would still get the same response times) 5) Are the maximum data rates using a channel attached CC limited by the terminals, CC, or the channel speed? 6) It seems amazing to me that a 327x type terminal can process information at 2.3Mb/s. Can it or does it only accept a buffer full of information and then stop? If it does have a "buffer full" state that is the primary regulating tool, then what is the buffer size of common terminals? 7) How does the CC multiplex/demultiplex inputs/outputs to/from the terminal? Is it packet(fixed/nofixed?) oriented? Any help on any of these questions would be so greatly appreciated. Thanks in Advance. Kim Tracy Room IH6k-234 AT&T Bell Laboratories Naperville-Wheaton Road Naperville,IL 60566 (312)979-6021 ..ihnp4!ihuxl!tracy