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Tue, 10 Jun 2025 14:12:25 -0400 (EDT) Received: by famine.localdomain (Postfix, from userid 1000) id 75EC49FCA9; Tue, 10 Jun 2025 11:12:24 -0700 (PDT) Received: from famine (localhost [127.0.0.1]) by famine.localdomain (Postfix) with ESMTP id 731659FCA8; Tue, 10 Jun 2025 11:12:24 -0700 (PDT) From: Jay Vosburgh To: Haylin Moore cc: netdev@vger.kernel.org Subject: Re: bond_eth_hash only uses the fifth byte of MAC address In-reply-to: References: Comments: In-reply-to Haylin Moore message dated "Tue, 10 Jun 2025 09:54:25 -0700." X-Mailer: MH-E 8.6+git; nmh 1.8+dev; Emacs 29.3 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1518703.1749579144.1@famine> Date: Tue, 10 Jun 2025 11:12:24 -0700 Message-ID: <1518704.1749579144@famine> Haylin Moore wrote: >Hello All, > >I am currently digging into the source code powering layer2+3 bonding >and saw that for bond_eth_hash only the 5th byte of both the source >and destination MAC address is used in the XOR. > >Is there a reason for this? I was not able to find anything searching >the mailing lists or the web. This functionality while documented just >feels weird to me. My recollection, which could be totally wrong, is that the described algorithm was chosen to mimic what was available on Cisco Etherchannel at the time. Bonding's balance-xor mode was originally developed to interoperate with Etherchannel, before LACP became popular, so this would have been implemented circa 2000-2002. Development on bonding was done out of tree at that time, and updates were distributed on sourceforge, with discussion primarily on the bonding-devel mailing list. marc.info has the bonding-devel list archived; you might be able to find the original discussion there. -J --- -Jay Vosburgh, jv@jvosburgh.net