Hi Remy, I have an alternative suggestion for comment 3; see below...
On Mon, Oct 26, 2020 at 6:30 AM Liubing (Remy) <[email protected]> wrote: > Hello Carles, > > I'm really sorry for this late reply. > > It seems that we have reached consensus on 4 of the 5 comments. Please > find my new response to your 3rd comment below. > > Thank you very much for reviewing. > > Best regards, > > Remy > -----邮件原件----- > 发件人: Carles Gomez Montenegro [mailto:[email protected]] > 发送时间: 2020年9月2日 17:54 > 收件人: Liubing (Remy) <[email protected]> > 抄送: [email protected]; [email protected] > 主题: Re: [6lo] Shepherd review of draft-ietf-6lo-plc > > Hello Remy, > > First of all, sorry for the late response. > > Thanks for taking my comments into consideration. > > Please find below my inline responses (labeled [Carles]): > > > Hello Carles, > > > > Thank you very much for your detailed review. > > [Carles] You are welcome! > > > We accept most of your suggestions. > > [Carles] Thanks! > > > Meanwhile, items that need further > > discussion are posted below. > > > > 1. This specification provides a brief overview of PLC technologies. > > Some of them have LLN characteristics, i.e. limited power > > > > Just a weak suggestion: LLN is a recognized term in many domains. > > Nevertheless, feel free to consider using "Constrained-Node Network > > (CNN) (see RFC 7228). > > [Remy] Maybe LLN is a better choice since it is used in many RFCs in > > IOT domain as well. Thank you for your suggestion though. > > [Carles] Feel free to use the term that you prefer. > > > 2. RPL (Routing Protocol for Low-Power and Lossy Networks) [RFC6550] > > is a layer 3 routing protocol. AODV-RPL [I-D.ietf-roll-aodv-rpl] > > updates RPL to include reactive, point-to-point, and asymmetric > > routing. IEEE 1901.2 specifies Information Elements (IEs) with > > MAC layer metrics, which can be provided to L3 routing protocol > > for parent selection. For IPv6-addressable PLC networks, a > > layer-3 routing protocol such as RPL and/or AODV-RPL SHOULD be > > supported in the standard. > > > > Why "SHOULD"? And if "SHOULD" is the right term here, perhaps add > > some clarification on reasons or circumstances motivating using a > > protocol different from RPL and/or AODV-RPL? > > [Remy] Yes, this sentence makes people confused. The reason why "SHOULD" > > is used is that we have other options like L2-routing and LOADng. But > > this sentence looks redundant now, because the whole section is > > talking about the three options. Do you think it is OK to remove this > sentence? > > [Carles] Yes, I agree to remove this sentence. > > > 3. IEEE 1901.1 supports 12-bit and 48-bit addresses. Header > > compression over IEEE 1901.1 will need some form of adaptation, since > > RFC 6282 refers to 16-bit and 64-bit addresses. > > [Remy] Yes, we need adaptation. How to generate IID from 12-bit > > (1901.1), 16-bit (G.9903 and 1901.2) and 48-bit address is defined in > > section 4.1 (Stateless Address Autoconfiguration). And using the same > > method, the original IPv6 address can be recovered from the L2 > > address. Thus that's where the adaptation is defined. It may be not > > explicit enough. Actually, the encoding format defined in RFC6282 > > applies to all the PLC technologies mentioned in this draft. The only > > difference is: for 1901.1, when the SAM or DAM in RFC6282 is set to 2, > > it means the source or destination IPv6 address is compressed to 12 bits > instead of 16bits. > > [Carles] In my opinion, adding some more explicit note would be helpful. > [Remy] I propose to add the following specification: > For IEEE 1901.2 and G.9903, the IP header compression follows the > instruction in [RFC6282]. However, additional adaptation MUST be considered > for IEEE 1901.1, since it has a short address of 12 bits instead of 16 > bits. The only modification is the semantics of the "Source Address Mode" > when set as "10" in the section 3.1 of [RFC6282], which is illustrated as > following. > > SAM: Source Address Mode: > If SAC=0: Stateless compression > > 10: 12 bits. The first 116 bits of the address are elided. The > value of the first 64 bits is the link-local prefix padded with > zeros. The following 64 bits are 0000:00ff:fe00:0XXX, where > XXX are the 12 bits carried in-line. > > If SAC=1: stateful context-based compression > > 10: 12 bits. The address is derived using context information and > the 12 bits carried in-line. Bits covered by context > information are always used. Any IID bits not covered by > context information are taken directly from their corresponding > bits in the 12-bit to IID mapping given by 0000:00ff:fe00:0XXX, > where XXX are the 12 bits carried inline. Any remaining bits > are zero. > > My concern with re-interpreting RFC6282 bits for particular 6lo specs is that it would potentially complicate existing tools like sniffers. One alternative is to left-justify 12-bit addresses in a 16-bit field and set the high-order four bits to zero. A similar technique was used for 8-bit MS/TP MAC addresses in RFC8163. Regards, Kerry > 4. PAN Coordinator (PANC) and PAN Device. The PANC is the primary > > coordinator of the PLC subnet and can be seen as a master node; PAN > > Devices are typically PLC meters and sensors. The PANC also serves > > as the Routing Registrar for proxy registration and DAD procedures, > > making use of the updated registration procedures in [RFC8505]. IPv6 > > over PLC networks are built as tree, mesh or star according to the > > use cases. Every network requires at least one PANC to communicate > > with each PAN Device. > > > > The last sentence was unclear. Who/What communicates with each PAN > > Device? > > [Remy] We meant "the PANC communicates with the PAN devices". We try > > to > > rephrase: Generally, each PLC network has one PANC. In some cases, the > > PLC network can have alternate coordinators to replace the PANC when > > the PANC leaves the network for some reason. > > [Carles] Your new proposed text looks good to me. > > > 5. What is the subnet model for the scenarios illustrated in this > > section? > > For example, is the "PLC subnet" a multilink subnet? Is each link in > > the "PLC subnet" a subnet? > > [Remy] It is a multilink subnet, instead of "each link is a subnet". > > [Carles] Thanks. Please add some text on this feature to the document. > > Best regards, > > Carles > > > > Best regards, > > Remy > > > _______________________________________________ > 6lo mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lo >
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