On May 27, 2008, at 9:26 AM, Jonathan Hui wrote: > > > The third issue is whether or not end-to-end mechanisms should be > used for recovery and congestion control. I think we agree that hop- > by-hop mechanisms are required regardless. They increase reliability > and can provide effective congestion control and mitigation. To me, > hop-by-hop mechanisms are generally much more effective than end-to- > end ones because they react to local conditions and can quickly > provide back-pressure all the way to the source. From a reliability > standpoint, we've seen solutions deliver >99.9% without end-to-end > recovery. So one question is how much more reliability do we really > need? and does it justify the added energy overhead and code size?
This is an excellent point. On one hand, it is critical that we do not preclude end-to-end recovery mechanisms, at the very least for the end- to-end argument. On the other, we might be getting a bit ahead of ourselves here; it's not clear at all whether the benefits of these mechanisms (increased layer 3 delivery ratios) significantly outweigh their costs (code size and energy). Phil _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
