Dear Pascal, I am confused again on the order of headers in the packets.
For example, the packet: *MAC header + (......) + ICMPv6*, The words "IP in IP then RPI then 6LoRH" equals to "*MAC header + (6LoRH IPinIP, 6LoRH-RPI, 6LoRH RH3, IPHC) + ICMPv6*", which we says RPI is RIGHT AFTER IPinIP is the first way I mentioned in the beginning of this email, no? Tengfei On Wed, Jan 20, 2016 at 9:45 PM, Pascal Thubert (pthubert) < pthub...@cisco.com> wrote: > OK, let us see. > > > > With the new text I just proposed, the source (normally that’s the root) > address of the packet with a RH3 is the reference for compression. So > Ideally we’d parse that before we parse the RH3 so we can decompress the > first address in the RH3. This is a change from the original text where I > expected the first address in the RH3 to be mostly in the full. So in 6LoRH > form, IP in IP would come before the RH3. > > > > With the next text, the root address may be elided but that means placing > an RPI to identify it if the network has more than one instance. To > decompress the IP in IP where the root is elided, one really needs the RPI. > So the RPI should be next to the IP in IP. I would probably have preferred > to place the RPI before the IP in IP but to look more like the uncompressed > format we might place the RPI right after the IP in IP. > > > > This would give (IP in IP then RPI then 6LoRH *) *. With this we’d > support multiple encapsulations though I cannot see where we’d need it for > now. > > > > Works? > > > > > > Cheers, > > > > Pascal > > > > *From:* Tengfei Chang [mailto:tengfei.ch...@gmail.com] > *Sent:* mercredi 20 janvier 2016 14:22 > *To:* Pascal Thubert (pthubert) <pthub...@cisco.com> > *Cc:* 6...@ietf.org; 6tisch@ietf.org > *Subject:* Re: [6tisch] The "BEFORE" and "AFTER" > > > > Thanks pascal for explaining! > > > > Yes, I vote to impose an order for the headers in the packet. It helps to > understand the format of packet generally. Thanks a lot! > > > > Tengfei > > > > On Wed, Jan 20, 2016 at 10:52 AM, Pascal Thubert (pthubert) < > pthub...@cisco.com> wrote: > > This is correct Tengfei, and quite classical. > > > > Headers are like a stack placed in front of the packet. One builds an > LOWPAN-IPHC – compressed packet that does not have any RPL artifact in it. > Then the RPL artifacts are added as 6LoRH headers. We have not imposed an > order yet but it makes sense to place the RPI first if any, then the RH3 if > any, then the 6LoRH. > > > > Would you wish that we impose an order to simplify the parsing? > > > > Pascal > > > > *From:* 6tisch [mailto:6tisch-boun...@ietf.org] *On Behalf Of *Tengfei > Chang > *Sent:* mercredi 20 janvier 2016 09:20 > *To:* 6tisch@ietf.org > *Subject:* [6tisch] The "BEFORE" and "AFTER" > > > > Dear all, > > > > As recently more discussion in the ML about the format of packet, > sometimes we say some header after/before the IPv6 header. I would like to > clarify this. > > > > 1. For me, I say with the way that mac header is the first header in the > packet and then, several Routing Headers are AFTER mac header (no mesh > header/fragmenet header in between). IPHC header is AFTER those Routing > Headers. > > > > 2. However, with the view of constructing a packet, IPHC is first added > into packet, then RHs are placed AFTER IPHC, MAC header is constructed at > the end. (I feel pascal is using this way to describe the order of header, > right?) > > > > What's the way when we describe something like this? > > > > Thanks > > Tengfei > > > > > > >
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