Re: [multipathtcp] draft-boucadair-mptcp-plain-mode-07

[Joe Touch <[e-mail]>]

On 6/3/2016 12:19 AM, [e-mail] wrote:
> Hi Joe,
>
> If you mean with dynamic routing a packet by packet routing decision, that could work however, how do you incorporate the path characteristic feedback into that decision. 
That's what multipath routing has been doing for years.

AFAIK, the mechanisms in MPTCP are an instance inspired by existing
multipath routing.

> Here the MPTCP mechanisms just come in handy and do the job quite well, but as you say we pay with some complexity. That complexity we feel,will have anyway with whatever solution we are going.

Perhaps, but MPTCP is the wrong solution for an IP tunnel for many reasons:

- it will layer congestion control on top of congestion control for all
transports in the payload IP that already support it (which they should)
- it fails to preserve payload IP messages inside a single TCP segment,
which increases loss due to a lack of fate-sharing and increases latency
and jitter
- by recovering from loss, it increases latency and jitter
- it can use only one load monitoring mechanism (the one built-in)
- it can use only one traffic distribution mechanism (the one built-in)

That's a lot of baggage vs. just using tunnels and existing dynamic
multipath routing -- and the latter doesn't require a new spec.

Joe