Nishida-san, Thank you very much for reviewing the draft. Please see my comments below. (2011/06/06 17:39), Yoshifumi Nishida wrote: > Hello, > I've reviewed this document as part of the transport area > directorate's ongoing effort to review key IETF documents. These > comments were written primarily for the transport area directors, but > are copied to the document's authors for their information and to > allow them to address any issues raised. The authors should consider > this review together with any other last-call comments they > receive. Please always CC tsv-dir@xxxxxxxx if you reply to or forward > this review. > > Summary: > > This draft specifies protocol for PANA Relay Element that can relay > messages between a PaC and a PAA where they cannot reach each other. > The proposed function is simple and straightforward and useful. > I couldn't find any transport related issues in the draft. > > > Minor comments: > > Please consider clarifying the following points. > > 1) I think clarifying communication model of this proposal will be > helpful for readers. > It seems to me that a PRE should communicate only one PAA. But, can a PAA > communicate multiple PREs? PANA allows multiple PAAs in an access network. For example, RFC 5192 defines a DHCP option to carry a list of PAA addresses and a PaC will choose one PAA to communicate with. Similarly, there can be multiple PAAs in an access network with PREs. In this case, a PRE will choose one PAA to communicate with for a given PaC. Next, a PAA can communicate with multiple PREs. We can clarify these in the draft. > > 2) The draft seems to presume PRE to be a multi-homed node. But, is > this mandatory > requirement? Is it possible to use single-homed node as a PRE? You are right, PRE can be either single-homed or multi-homed. In fact, in ZigBee IP, each mesh router is a PRE having a single 802.15.4 radio interface. We can clarify this in the draft as well. > > 3) Is it possible to place a PRE behind NAT? Is there any concern for this? > There are two cases, (i) a NAT between a PaC and a PRE, and (ii) a NAT between a PRE and a PAA. I don't see a NAT issue specific to PANA relay for both cases. > 4) How p2 (PRE-assigned UDP port number) is determined? Is it possible to use > ephemeral port? If so, the protocol will need to be robust > against PRE rebooting. > Similarly, can we use dhcp-ed address for IP2b? Yes, p2 can be ephemeral. Since a PAA just uses the UDP and IP headers received from the relay to generate UDP and IP headers of its response PRY to the relay, I think the protocol is robust against PRE rebooting. For the same reason, use of DHCP-ed address for IP2b works. Even when IPsec is used between a PRE and a PAA, I think DHCP-ed address for IP2b works as long as IKEv2 identity for the PRE is not based on IP address. Kind Regards, Yoshihiro Ohba > > Regards, > -- > Yoshifumi Nishida > nishida@xxxxxxxxxxxxxx > _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf