Subject: Re: connection bonding?
To: None <>
From: Steven M. Bellovin <>
List: tech-net
Date: 12/07/2005 23:13:31
In message <>,
>In message <>,
>"Steven M. Bellovin" writes:
>>In message <200512072235.RAA20918@Sparkle.Rodents.Montreal.QC.CA>, der Mouse 
>>>One of the most bothersome things about agr(4), to me, is that which
>>>link a packet goes out seems to depend on nothing but a hash of
>>>assorted data related to the packet.  This means that if links of
>>>different speeds are aggregated, the slower one(s) will get overloaded.
>>>I'd expect it to simply pick the interface with the shortest output
>>That's mostly a feature...
>[.. discussion of TCP reordering and vendors who got it wrong ...]
>Hi Steve,
>In fact, it's more than a feature, it's a _requirement_.
>IEEE 802.3ad requires that all packets (frames, in layer2-speak) in a
>flow not be reordered (or htat they traverse the same path through a
>link-aggreation group, I forget the exact wording, but the intent is
>unmistakably clear. At least to anyone with our shared backgorund).
Yup -- it's a requirement precisely because of the problems I outlined. 
I was speaking more poetically when I phrased it as a I did.

		--Steven M. Bellovin,