Date: Thu, 12 Apr 2007 17:11:29 +1000 From: Peter Jeremy <peterjeremy@optushome.com.au> To: Arne Schwabe <schwabe@uni-paderborn.de> Cc: freebsd-current@freebsd.org Subject: Re: CFT: new trunk(4) Message-ID: <20070412071129.GA834@turion.vk2pj.dyndns.org> In-Reply-To: <461D52B6.2080200@uni-paderborn.de> References: <20070402092830.GB28809@heff.fud.org.nz> <E1Hbd6G-0000LG-MX@clue.co.za> <20070411191450.GE815@turion.vk2pj.dyndns.org> <461D52B6.2080200@uni-paderborn.de>
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--azLHFNyN32YCQGCU Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2007-Apr-11 23:27:18 +0200, Arne Schwabe <schwabe@uni-paderborn.de> wrot= e: > >>Trunking is a way of combining multiple physical interfaces to increase >>the bandwidth. Trunking multiple VLANs on a single interface doesn't >>make sense to me. >> =20 >Cisco calls this Trunk (multiple vlans over one physical connection=20 >(with dot1q)). Combining multiple physical links is called channel.=20 >Maybe that is were the confusion comes from. Mea cupla. I knew that - maybe I should do a better job of getting the brain into gear before responding. I'll justify my incorrect terminology by claiming that it seemed consistent with the usage implied by the original poster. >>At least some of the proprietary protocols >>are fairly dumb and just round-robin MAC addresses between the >>physical links rather than dynamically sharing traffic across the >>available links. The former means that if most or all of your traffic >>is for a single MAC address, you don't actually gain anything by >>having multiple physical links. > >I have seen things break if you do real round robin, To clarify, my reference to "round-robin" may have been unclear. The equipment I've seen will assign a MAC address to a physical port as part of the MAC learning process. All traffic to that MAC address is then forwarded via that port. > some pxe boot stuff=20 >and other embedded tcp/ip stack which are intended for local network use= =20 >only don't like if packets are out of order, I believe that the Ethernet standard requires in-order delivery. This makes real dynamic traffic sharing non-trivial. The round-robin port assignment ensures in-order delivery and will probably achieve reasonable load balancing if traffic is distributed across a number of MAC addresses. --=20 Peter Jeremy --azLHFNyN32YCQGCU Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFGHduh/opHv/APuIcRAvkCAKCaubumom7Hs9Fxk7AKlVxNz5gYBwCgiN2M QXHn69rHb4tuc7jAzbRVfII= =aTHX -----END PGP SIGNATURE----- --azLHFNyN32YCQGCU--
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