[6949] in North American Network Operators' Group
Re: Questions about Internet Packet Losses
daemon@ATHENA.MIT.EDU (Howard C. Berkowitz)
Tue Jan 14 05:42:46 1997
In-Reply-To: <199701140625.WAA25048@chimp.jnx.com>
Date: Tue, 14 Jan 1997 05:29:20 -0500
To: Tony Li <tli@jnx.com>
From: "Howard C. Berkowitz" <hcb@clark.net>
Cc: nanog@merit.edu
Tony,
Thanks for posting some useful raw data. A clarification -- in some
messages, you say you've stripped headers, but is unclear if you did so in
your top 10 table.
If so, 41 sounds reasonable for noncompressed-header Telnet, with the 44,
52, 48, 56, etc., sizes, as a guess, to a rounded-up transmission buffer.
44 in implementation where memory is allocated/managed in 4 byte quanta, 52
in 8 byte quanta, etc.
Silly question, at 5AM...MSS is one of those acronyms I use for its own
convenience and beauty, without really stopping to think what it stands
for...Mean Segment Size?
>
>Unanswered questions for further research:
>1) What in hell is sending so many 40 byte packets? Are we really seeing
> productive ACKs? Or is it just HTTP bogosity? This really sucks.
>2) What OS is using a 512 MSS? 256?
>3) What are the minimal revs of various BSD flavors to exceed the 576 MTU
> by default?
>4) 41 bytes is pretty obviously interactive traffic. Is the intuition
> correct? What's so special about 44, 52, 48 and 56? What do people do
> with 4, 8, 12 and 16 bytes of data? And why not any of the odd values?
>
>Tony
>
> Tony's Top 10
>Packet Size Percentage
>40 44.838 "ACKs, SYNs, FINs, RSTs "
>552 9.19 512 MSS
>1500 6.839 Happy boxes
>576 5.779 BSD bogosity
>44 4.719 ??
>52 1.175 ??
>48 0.884 ??
>41 0.776 ??
>56 0.73 ??
>296 0.717 256 MSS
