Hi Carsten, Prima facie, I think fragment forwarding might help, having said i need to still understand the implications of the revised design(and there are reservations i have). Implementation-wise, it may not be difficult to try out and would consider it ... Regardless, my point was, working on fragmentation would be well worth the time spent, be it fragment-forwarding or if there is a possibility of any thing more improved!
Regards, Rahul p.s. pls chk inline as well. On 6 April 2017 at 19:27, Carsten Bormann <[email protected]> wrote: > Hi Rahul, > > this sounds as if fragment forwarding would help already? > (Am I reading this right that the discards are buffer space discards, not > retransmission count packet losses?) > [RJ]: Yes buffer space discards, but it results in more retransmissions causing more mac send failures. > > Grüße, Carsten > > > On Apr 6, 2017, at 15:39, Rahul Jadhav <[email protected]> wrote: > > > > Hi Carsten, > > > > Currently I m reassembling hop by hop. > > > > Problem begins with initial auth session itself!! I use PANA for network > access in single channel (with no RDC) mesh and the payload in most PANA > messages crosses 127B (especially considering the relay header overhead),,, > its all unicast with MAC layer ACK. None of my mcast packets cross MTU > boundary. Also an imp point is that the buffer space is only for one IPv6 > datagram (i.e. 1280B). > > Some of the problems highlighted by Pascal such as, fragments getting > discarded prematurely for e.g. because of high node density causing > reception from different peers is hurting the end to end msg transmission > badly. The failure rate and thus the retransmission rate at app is very > high,, so much that we had to adopt a proprietary compressed PANA > signalling mechanism to improve convergence time. > > > > Regards, > > Rahul > > > > On 6 April 2017 at 18:24, Carsten Bormann <[email protected]> wrote: > > On Apr 6, 2017, at 10:57, Rahul Jadhav <[email protected]> wrote: > > > > > > Fragmentation at 6lo layer as it is today is almost unusable for a > moderately sized network with lower MTUs such as 127B. > > > > Hi Rahul, > > > > please explain some more. > > > > What kind of problem do you experience? > > > > Is the load on your network predominantly composed of packets > 127 B? > > > > Are you using MAC-layer ACK? > > > > Do the problems you are seeing occur with Unicast or with Multicast? > > > > Are you already using fragment forwarding or are you reassembling hop by > hop? > > > > Grüße, Carsten > > > > > > _______________________________________________ > > 6tisch mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/6tisch > >
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