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Date: Mon, 08 Aug 2011 17:59:28 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Lamparter <equinox@...c24.net>
Cc: Phillip Susi <psusi@....rr.com>, netdev@...r.kernel.org
Subject: Re: 802.3ad bonding brain damaged?
Le lundi 08 août 2011 à 09:57 +0200, David Lamparter a écrit :
> Am Sonntag, den 07.08.2011, 15:52 -0400 schrieb Phillip Susi:
> > - From Documentation/networking/bonding.txt:
> >
> > Additionally, the linux bonding 802.3ad implementation
> > distributes traffic by peer (using an XOR of MAC addresses),
> >
> > This is counter to the entire point of 802.3ad. Distributing traffic by
> > hash of the destination address is poor mans load balancing for
> > systems not supporting 802.3ad.
>
> No, it isn't. 802.3ad/.1AX explicitly requires that no packet
> re-ordering may ever occur, which can only be guaranteed by enqueueing
> packets for one host on one TX interface. This behaviour is mandated by
> 802.1AX-2008 page 15 which reads:
>
> This standard does not mandate any particular distribution
> algorithm(s); however, any distribution algorithm shall ensure that,
> when frames are received by a Frame Collector as specified in 5.2.3,
> the algorithm shall not cause
> a) Misordering of frames that are part of any given conversation, or
> b) Duplication of frames.
> | The above requirement to maintain frame ordering is met by ensuring
> | that all frames that compose a given conversation are transmitted on a
> | single link in the order that they are generated by the MAC Client;
> hence, this requirement does not involve the addition (or
> modification) of any information to the MAC frame, nor any buffering
> or processing on the part of the corresponding Frame Collector in
> order to reorder frames. This approach to the operation of the
> distribution function permits a wide variety of distribution and load
> balancing algorithms to be used, while also ensuring interoperability
> between devices that adopt differing algorithms.
>
It all depends on the definition of 'conversation'
Phillip assumed two (or more) TCP flows from machine A to machine B
could use two different links, while you assert they MUST use a single
link.
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