[lp-wan] Fw: re-order header field request
"weigengyu" <weigengyu@vip.sina.com> Wed, 21 June 2017 02:45 UTC
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Subject: [lp-wan] Fw: re-order header field request
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Hi, There is a question about Format in draft-ietf-lpwan-ipv6-static-context-hc-04. > So I think, we need to maintain same order on all fragment headers. > existing; > <------------ R ----------> > <--T--> 1 <--N--> > +-- ... --+- ... -+-+- ... -+ > | Rule ID | DTag |W| CFN | > +-- ... --+- ... -+-+- ... -+ > > shall be; > <------------ R ----------> > <--T--> <--N--> 1 > +-- ... --+- ... -+- ... -+-+ > | Rule ID | DTag | CFN |W| > +-- ... --+- ... -+- ... -+-+ > > and for the last fragment > <------------ R ----------> > <--T--> <--N--> > +-- ... --+- ... -+- ... -+-+ > | Rule ID | DTag | CFN |MIC > +-- ... --+- ... -+- ... -+-+ > > what do you think? > Why each successive fragment must contain a Rule ID? It is known that the DTag is used as an indication of fragments belonged to the same IPv6 packet. A Rule ID in the first fragement can be passed to the receiver how to do HC compression, but the successive fragments containing a Rule ID just send a redundent information to the receiver. Right? Regards, Gengyu WEI Network Technology Center School of Computer Beijing University of Posts and Telecommunications -----原始邮件----- From: Carles Gomez Montenegro Sent: Wednesday, June 21, 2017 12:01 AM To: Arun Cc: lp-wan ; Laurent Toutain ; Ana Minaburo Subject: Re: [lp-wan] re-order header field request Hi Arun, Thanks for pointing this out. Your proposal seems fine to me, except for the (possibly minor) detail that in your proposal "R" would comprise a number of header fields for the last fragment that would be different from the number of fields in previous fragments. Maybe we could also consider another solution: adding the W bit in the header of the last fragment of the packet. I haven't found examples of scenarios where the W bit is actually needed in the last fragment (i.e. fragment with "all ones" CFN). However, I'm wondering if there is an actual benefit or a related use case that may require *not* having a W bit in the last fragment header. (If anyone has any in mind, please chime in!) On the other hand, if we have the W bit also in the last fragment header, header format will be more uniform across all fragments. Thoughts? Cheers, Carles > Hi all, > Absence of window bit in the last fragment of the packet makes it tricky > to unmarshall the header at the receiver. > As I see it, the receiver up front shall know the length of the CFN > field depending on the Window size configured but doesn't know to > anticipate the last fragment unless indicated by CFN. > So I think, we need to maintain same order on all fragment headers. > > existing; > > <------------ R ----------> > <--T--> 1 <--N--> > +-- ... --+- ... -+-+- ... -+ > | Rule ID | DTag |W| CFN | > +-- ... --+- ... -+-+- ... -+ > > shall be; > <------------ R ----------> > <--T--> <--N--> 1 > +-- ... --+- ... -+- ... -+-+ > | Rule ID | DTag | CFN |W| > +-- ... --+- ... -+- ... -+-+ > > and for the last fragment > <------------ R ----------> > <--T--> <--N--> > +-- ... --+- ... -+- ... -+-+ > | Rule ID | DTag | CFN |MIC > +-- ... --+- ... -+- ... -+-+ > > > what do you think? > > > thanks, > Arun > > _______________________________________________ > lp-wan mailing list > lp-wan@ietf.org > https://www.ietf.org/mailman/listinfo/lp-wan > _______________________________________________ lp-wan mailing list lp-wan@ietf.org https://www.ietf.org/mailman/listinfo/lp-wan
- [lp-wan] re-order header field request Arun
- Re: [lp-wan] re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] re-order header field request weigengyu
- [lp-wan] Fw: re-order header field request weigengyu
- Re: [lp-wan] re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] re-order header field request Arun
- Re: [lp-wan] re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] re-order header field request Laurent Toutain
- Re: [lp-wan] re-order header field request Arun
- Re: [lp-wan] re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] re-order header field request weigengyu
- Re: [lp-wan] Fw: re-order header field request weigengyu
- Re: [lp-wan] Fw: re-order header field request Arun
- Re: [lp-wan] Fw: re-order header field request weigengyu
- Re: [lp-wan] Fw: re-order header field request அருண்பிரபு (arunprabhu)
- Re: [lp-wan] Fw: re-order header field request weigengyu
- Re: [lp-wan] Fw: re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] Fw: re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] Fw: re-order header field request weigengyu
- Re: [lp-wan] Fw: re-order header field request Pascal Thubert (pthubert)
- Re: [lp-wan] Fw: re-order header field request weigengyu
- Re: [lp-wan] Fw: re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] Fw: re-order header field request weigengyu
- [lp-wan] lpwan-overview comments Alper Yegin
- Re: [lp-wan] lpwan-overview comments Alexander Pelov
- Re: [lp-wan] lpwan-overview comments Alper Yegin
- Re: [lp-wan] Fw: re-order header field request Arun
- Re: [lp-wan] Fw: re-order header field request Carles Gomez Montenegro
- Re: [lp-wan] Fw: re-order header field request Laurent Toutain
- Re: [lp-wan] lpwan-overview comments Stephen Farrell
- Re: [lp-wan] lpwan-overview comments Stephen Farrell
- Re: [lp-wan] lpwan-overview comments Alper Yegin
- Re: [lp-wan] lpwan-overview comments Stephen Farrell
- Re: [lp-wan] Fw: re-order header field request Pascal Thubert (pthubert)
- Re: [lp-wan] lpwan-overview comments Alper Yegin
- Re: [lp-wan] lpwan-overview comments Stephen Farrell