[net.info-terms] Need info: 327x terminal & cluster cont. trans.speeds&perfor.

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