[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: successful termination?



On Apr 5, 2009, at 2:14 PM, Brian E Carpenter wrote:
Hi Lixia,

On 2009-04-05 16:53, Lixia Zhang wrote:

On Apr 4, 2009, at 6:58 PM, Brian E Carpenter wrote:

Jari,

If I look at both Geoff's and Olivier's (relayed) comments,
it's clear to me that there is work to be done.

I agree that the address-pair selection issue is broader
than just shim6 (and is related to other things, such as
egress router selection). But there may still be some work
do here, on 'SHIM6 Requirements for Address Pair Selection',
even if the actual specification belongs in 6MAN.

I agree that there is commonality of interest with multipath
transport, but it's far from clear to me that there is
actual overlap in the mechanisms; SHIM6 is a layer 3 shim,
and multipath transport sure seems like a layer 4 shim,
which was a direction that MULTI6 explicitly choose not to
follow up.

I wondered how to interpret the phrase "actual overlap" in the above... yes one solution works at transport and the other works at layer 3, so
yes in terms of layers they are not at the same place.
But in terms of goals, would you agree that their goals overlap?

Sort of. But the shim6 goals were clearly aimed at RFC3582,
whereas I understand the goals of multipath transport to be
more aimed at load sharing, with failover as a secondary effect.
However, the mechanisms are so different that I don't see anything
to gain by sticking them in the same room at the IETF.

Personally I see both having a goal of utilizing multiple paths, whether one at a time or multiple in parallel (isn't the former a special case of the later). I would not make load sharing and failover as two necessarily separated issues. I believe the two are closely related to each other. For example multipath-TCP detect path failures through its simultaneous transmission over multiple paths, and conversely this simultaneous transmission over multiple paths makes its performance less dependent on prompt detection of the failure of any single path. (And I have not mentioned the benefit of utilizing TCP's built-in feedback look for failure detection instead of pure overhead probing packets...)

Lixia