Re: [Banana] Reaching Consensus on Problem Statement

[Brian Trammell <[e-mail]>]

hi Mingui, Michael, all,

inline below...

> On 03 Feb 2017, at 10:40, Mingui Zhang <[e-mail]> wrote:
> 
> Hi Michael,
> 
>> -----Original Message-----
>> From: Banana [mailto:[e-mail]] On Behalf Of Michael Menth
>> Sent: Friday, February 03, 2017 2:53 AM
>> To: [e-mail]
>> Subject: Re: [Banana] Reaching Consensus on Problem Statement
>> 
>> Dear Margaret,
>> 
>> thanks a lot for your initiative!
>> 
>> The scope may depend on where the load balancer and recomination point are
>> located. In the network similar to draft-zhang-gre-tunnel-bonding-01.txt (GRE
>> Tunnel Bonding) or MPTCP-Proxy, or on the endpoints like pure MPTCP?
>> Probably focus is on the first, but the text doesn't say so, yet.
> 
> According to my understanding, the scope might as well be applicable to the network with MPTCP-Proxy. And surely, it does not include the network with pure MPTCP endpoints.
> 
>> I can imagine that the load balancing option (per-packet or per-flow) may be
>> minor. Both may be justified for performance reasons depending on networking
>> conditions. Therefore, I wouldn't rule out per-flow load balancing but a priority
>> on per-packet may be reasonable to start with.
> 
> But there are solutions for per-flow load sharing already. Think about the widely used and standardized hashing methods. I think it’s non-necessary to mention per-flow load sharing issue in the problem statement. Otherwise, the problem statement would look like encouraging reinventing something.

Speaking personally, no Seoul-BoF-chair or other hats on:

Let me slightly restate the question here. Will a BANANA-balanced network with two links to the Internet with available downstream data rates A and B (such that A >= B) will ever need to support a single flow with a sustained data rate > A?

If not, we can take existing work on per-flow load balancing off the self. If so, we need to invent something.

In scenarios where there is no dominant flow, or where A >> B, the extra complexity of splitting flows across links is not worth the additional complexity. However, in scenarios where one flow dominates, i.e., the majority of the data rate demand is covered by a single flow, and where rates A and B are relatively comparable, per-flow load balancing leaves a lot of available bandwidth on the table, and the complexity tradeoff becomes more worth it.

So for me this question reduces to which scenario is more common.

Cheers,

Brian