netdev - Proper value for bandwidth parameters

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <1328716704.3310.36.camel@denise.theartistscloset.com>
Date:	Wed, 08 Feb 2012 10:58:24 -0500
From:	"John A. Sullivan III" <jsullivan@...nsourcedevel.com>
To:	netdev@...r.kernel.org
Subject: Proper value for bandwidth parameters

Hello, all.  From a system administrator's perspective, do I need to
reduce the values I feed to bandwidth defining parameters in tc such as
the ul m2 values in HFSC?

For example, if I have a 1.544 mbits circuit and I set HFSC ul m2 to
1544kbits (or any other bandwidth parameter in different algorithms),
when it calculates its timer for dequeuing the packet (let's assume a
full sized 1500 byte packet) is it performing the calculation on 1500
bytes or 1500 bytes plus overhead such as the Ethernet header, CRC,
preamble, and IFG?

I am assuming it is based upon the 1500 byte packet in the above
example.  In which case, I think I need to reduce my bandwidth value fed
to tc to account for the overhead lest I exceed the real bandwidth.  For
example, the full sized Ethernet packet will be somewhere around 1538
bytes so 1500/1538 * 1.544 = 1505kbits.  Is that correct? Is there a
guideline for a multiplier to use? I suppose if we are flooding a link,
it is most likely with full sized packets.  Thanks - John

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html