<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div>Well, MRC was receiving "suggestions" from Stu Grossman on how to do it, but<br></div><div>if my memory does not fail me the block size was 312, due to lack of buffer space<br data-mce-bogus="1"></div><div>in the already crammed single section 512KW 2020. I'm afraid my tape and disk-pack<br data-mce-bogus="1"></div><div>are in Seattle. I knew it was not 576 as it had two DUP-11's and using it for transit failed... <br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Quiz, do you knew what a DDP is?<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>-P<br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"tommytimesharing" <tommytimesharing@gmail.com><br><b>To: </b>"hecnet" <hecnet@Update.UU.SE><br><b>Sent: </b>Friday, January 15, 2021 3:59:25 PM<br><b>Subject: </b>Re: [HECnet] Thousands of DECnet errors on Tops-20<br></blockquote></div><div data-marker="__QUOTED_TEXT__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><p>Was this maybe that magical version 5 of Tops-20 that MRC put
together for the 2020? I sure would love to see the sources for
that! I'm not sure if this is relevant, but the following macro
in D36COM is of interest:<br>
</p>
<blockquote><font size="+1"><tt>DEFINE KNMMCS,<</tt><tt><br>
</tt><tt>; Symbol,Name,Cost, Maximum receive block
size</tt><tt><br>
</tt><tt> KNMMAC LD.TST,TST, 1, 0
;TST DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.DTE,DTE, 3,
<^D576> ;DTE DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.KDP,KDP, 4,
<^D576> ;KDP DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.DDP,DDP, 5,
<^D576> ;DDP DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.CIP,CI, 2,
<^D576> ;CI DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.NI ,NI, 1,
<^D1504-%RTEHS> ;NI DEVICE</tt><tt><br>
</tt><tt> KNMMAC LD.DMR,DMR, 2,
<^D576> ;DMR DEVICE</tt><tt><br>
</tt><tt>>;END OF KNMMCS</tt></font><br>
</blockquote>
<p>What can be seen is that the maximum block size is 576 in <u>all</u>
cases except the NI, which is 1476 bytes. I don't know if any of
these devices are relevant to the 2020; one assumes that the DTE,
CI and NI are not.<br>
</p>
<blockquote>
<div style="font-family:'arial' , 'helvetica' , sans-serif;font-size:12pt;color:#000000">
<div>
<hr width="100%" size="2">On 1/12/21 3:29 PM, Peter Lothberg
wrote:<br>
<div><br>
</div>
The DECnet segment size has to be the same "network wide".<br>
</div>
<div><br>
</div>
<div>If I remember right DECnet looks at the two end nodes and
uses the smalles segment size, <br>
</div>
<div>so if there is any transit node in the path with a small
segment size things will not work as <br>
</div>
<div>it will drop packets bigger than it''s size.<br>
</div>
<div><br>
</div>
<div>The only SW/HW combination I knew of that has other than
576 is MRC/Stu DECnet for <br>
</div>
<div>Tops20 4.x on DEC2020.<br>
</div>
<div><br>
</div>
<div>-P<br>
</div>
<div><br>
</div>
</div></blockquote><br></blockquote></div></div></body></html>