On Fri, Aug 24, 2018 at 12:34 PM, Templin (US), Fred L <fred.l.temp...@boeing.com> wrote: > Hello, > > As document shepherd, I am required to perform a review. Please see below > for initial comments, and respond on the list. > Hi Fred,
Thanks for shepherd review and comments! Some response inline. Tom > Fred > > --- > > Overall: > > The document is well written and clear. The only thing I wonder is whether > this > document needs to be progressed in conjunction with GUEEXTEN or whether it > can go forward independently. In particular, this draft defines a flags > registry > under IANA Considerations but with no initial assignments. Instead, initial > assignments are assumed to be requested in GUEEXTEN. TBD is whether the > two documents can be progressed together. > The flags field is defined as part of the core GUE header, but the actual extensions are defined elsewhere. I would like them separate since that highlights the fact that GUE is exensible. We can move the IANA request to GUEEXTEN if that makes more sense. > Section by Section comments: > > Section 3.2.1: > Final paragraph beginning: "IP protocol number 59 ("No next header") can be > set > to indicate that the GUE payload does not begin with the header of an IP > protocol." > The example given was GUE fragmentation, but would that not represent a > departure from the way things are done for IP fragmentation? I believe in > IP fragmentation the protocol field contains the same value for both initial > and non-initial fragments. Is there a reason for the departure here? Yes. GUE allows a node to skip over the GUE header to inspect the encapsulated payload, For instance, a firewall may be looking for an inner IP destination in an encapsulated packet. The GUE payload is interpreted based on the protocol in the Proto/ctype field. So if the payload is not a parseable IP protocol (like it would be for a non-first GUE fragment), then 59 is used to avoid devices trying to parse it. > > Section 3.2.2: > Final sentence: "This document does not specify any standard control message > types other than type 0." If this document defines type 0, then the format and > use of that message type should be specified here. Also, IANA considerations > simply says: "Need Further Interpretation" - I think that interpretation > should > appear in this document. It's the control message equivalent of IP protocol 59 as discussed above. The payload is a control message (or at least part of one) but cannot be parsed with addition context (like a reassembled packet, after a GUE transform, etc.). > > Section 3.3: > The use of "flags" and "paired flags" is discussed but with no actual flags > assignments appearing in this document. Instead, it quotes from "GUEEXTEN". > Is that OK? > The reference to GUEEXTEN is not material and can be removed. > Section 4: > Misspelled "varinant". Check rest of document for spelling. > Okay. > Section 5: > Final sentence of first paragraph, suggest changing: "Packet flow in the > reverse > direction need not be symmetric; GUE encapsulation is not required in the > reverse path." to: "Packet flow in the reverse direction need not be > symmetric; > for example, the reverse path might not use GUE and/or any other form of > encapsulation." > Okay. > Section 5.4: > The sentence "No error message is returned back to the encapsulator." Suggest > removing this sentence and remain silent. Reason is that future variants may > well indicate the use of some form of error messaging. > Okay. > Section 5.4.1: > Second paragraph, "set 94 for IPIP", I was under the impression that the > common > values for IPIP encapsulation are '4' for IPv4 and '41' for IPv6. I have not > seen '94' > appear elsewhere. Is this a common use? If not, would it be better to use '4' > or '41'? > Correct, 4 should be used for IPv4 and 41 should be used for IPv6 encapsualtion in examples. > Section 5.5: > The sentence including: "there are no provisions to automatically GUE copy > flags" > appears to have a wording issue that I could not parse. Okay, will fix. > > Section 5.11: > Is "flow entropy" mandatory or optional? For example, shouldn't it be OK for > the > encapsulator to set the UDP source port to anything of its own choosing if it > does > not want to get involved with flow entropy determination? >From section 5.6.1: "The selection of whether to make the UDP source port fixed or set to a flow entropy value for each packet sent SHOULD be configurable for a tunnel. The default MUST be to set the flow entropy value in the UDP source port." Is more clarificaiton needed? > > Section 6.2: > "Generic UDP Encapsulation for IP Tunneling (GRE over UDP)" - the correct > title > of this RFC is "GRE-in-UDP Encapsulation". > Okay, will fix. > Section 6.2: > "Generic UDP tunneling [GUT]" expired in 2010. Can we either drop this or > refer > to it in the past tense? > Okay, can delete it. > Section 8.3: > Control type 0 defined as: "Need further interpretation". I think this > document > should say what type 0 is instead of just requesting a "placeholder". It's not really a placeholder. If means the playload contains a control message bu requires further context to be interpreted. > > Section 8.4: > It seems unusual that this document requests a registry with no initial > assignments. If it makes sense the IANA request could be moved to GUEEXTEN. > > _______________________________________________ > Int-area mailing list > Int-area@ietf.org > https://www.ietf.org/mailman/listinfo/int-area _______________________________________________ Int-area mailing list Int-area@ietf.org https://www.ietf.org/mailman/listinfo/int-area