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Date:      Wed, 7 Aug 1996 10:59:18 -0500 (CDT)
From:      Mark Tinguely <tinguely@plains.nodak.edu>
To:        brian@MediaCity.com, freebsd-atm@freebsd.org
Subject:   Re: IDT NicStar and non-compliant use
Message-ID:  <199608071559.KAA21656@plains.nodak.edu>

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I am back from vacation, I did recieve my two IDT NICStAR cards, and I
am planning to start the work on the driver.

I bought two cards because this will be a bootstrapped effort. I will
directly connect the two cards using a twisted cable. set the one card
in a permanent send mode, sending a test PDU. on the other card, I can use the
input to get the packet recieving code to work. after that I planned to work
on the transmission of PDUs. there will be a massive amount of work require
to implement the UNI 3.1 layer.

This project will appreciate help from anyone willing to help. I will take
advantage of your offer now.  I am not sure if I understand how the
IDT NICStAR restricts the transmission rate using the fixed rate connection.

With varible bitrate there are three queues and these queues are prioritized
and we also we supply the N and M in the Transmit Buffer Descriptor
(see page 32 of IDT77201 NICStAR User Manual) to regulate the data rate.

Each fixed rate connection has its own transmission queue. I am guessing the
data rate is set by manually adjusting how often we schedule the SCD in the
Transmit Schedule Table. This is difficult because each entry in the Transmit
Schedule Table can hold a different size PDU. A run through the Transmit
Schedule table would be done faster if there is nothing else to be sent than
if the table is full. Does anyone else have an opinion on this?

--mark.



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