Re: [6tisch] MSF adapts to traffic only for secured packets

Yasuyuki Tanaka <yasuyuki.tanaka@inria.fr> Fri, 06 December 2019 20:31 UTC

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To: pthubert@cisco.com, Tengfei Chang <tengfei.chang@gmail.com>
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From: Yasuyuki Tanaka <yasuyuki.tanaka@inria.fr>
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Subject: Re: [6tisch] MSF adapts to traffic only for secured packets
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Hi Pascal, Tengfei,

On 12/6/2019 6:48 PM, Tengfei Chang wrote:
> Yes, MSF indeed aware of the routing information such as RPL parent, I 
> consider this is like an information stored at IPv6 layer that MSF can 
> read it from without touching the frame L2 payload.
> In such sense, I could consider the DSCP value can be another 
> information stored at upper layer that MSF have read access to it..

I think these two are different things...

Handling DSCP value will be a per-packet process. Can we pass DCSP value 
to the TSCH layer using the interface for transmission defined by 
IEEE802.15.4? I don't think so.

I don't see any problem in allocating additional cells for "acceptable" 
amount of traffic including relayed join requests. To prevent 
application packet drops, such allocations could be a good thing.

Rather than giving some L3 information to L2, the L3 may need L2 
information, like available bandwidth (cells) for a certain link. For 
the MSF case, if the IPv6 layer on an intermediate node limits outgoing 
traffic of relayed join requests below 20% of available bandwidth, 
undesired cell allocations could be avoided, assuming 
LIM_NUMCELLSUSED_HIGH is 75% and the link has almost the perfect link PDR.

Best,
Yatch