[nos-bbs] MAXFRAME

Michael E Fox - N6MEF n6mef at mefox.org
Mon Jun 9 19:54:12 EDT 2014


Yes, the manual states the optimal value is 1 but gives no reason or
explanation of why.

My email asked for the why.


-----Original Message-----
From: nos-bbs-bounces at tapr.org [mailto:nos-bbs-bounces at tapr.org] On Behalf
Of Charles Hargrove
Sent: Monday, June 09, 2014 3:28 PM
To: nos-bbs at tapr.org
Subject: Re: [nos-bbs] nos-bbs Digest, Vol 118, Issue 1

I have been using a value of 1 ever since I first set up my system back in
late 90's.  The JNOS manual was my guide and it makes sense.

>From the JNOS manual:

ax25 maxframe [<count>]
Establish the maximum number of frames that will be allowed to remain
unacknowledged at one time on new AX.25 connections. This number cannot be
greater than 7. Without <count> it will display the current setting. Note
the maximum outstanding frame count only works with virtual connections. UI
frames are not affected. Also note that for optimal performance, a value of
should be used.  Default is 1 frame.


1.2. Maxframe
This parameter controls the number of I-frames that may be send on an AX.25
connection before it must stop and wait for an acknowledgement. Since the
AX.25/LAPB sequence number field is 3 bits wide, this number cannot be
than 7. It can be shown that the optimal value is 1.

Since unconnected-mode (datagram) AX.25 uses UI frames that do not have
sequence numbers, this parameter does not apply to unconnected mode.

> I'm trying to optimize the value of MAXFRAME.
> I've seen statements on the web such as "for best efficiency, use MAXFRAME
> 1", but no evidence or explanation is provided.  In fact, a window size of
> just one is usually the LEAST efficient way to go.
> So, what are you guys using for MAXFRAME out there?
> Why?
> How did you decided on that value?
> Do you have any evidence (experimental, annectdotal, or otherwise) that
> you to use that value?

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