On Mon, May 16, 2022 at 4:47 PM Robert Moskowitz <rgm-...@htt-consult.com> wrote:
> Thanks, Daniel for the update. > > Now some comments. > > The necessary state is held within the IPsec Security Association and > > The document specifies the necessary parameters of the EHC Context to > allow compression of ESP and the most common included protocols, such > as IPv4, IPv6, UDP and TCP and the corresponding EHC Rules. > > Should any reference be made to cipher compression? At least reference > to 8750? Or since this is just the abs > sure we can, but the transform itself is a bit outside EHC. > > It also > defines the Diet-ESP EHC Strategy which compresses up to 32 bytes per > packet for traditional IPv6 VPN and up to 66 bytes for IPv6 VPN sent > over a single TCP or UDP session. > > > In UDP transport I am reducing 18 bytes (assuming cipher with zero > padding) to 4 bytes. Also worth noting here... > > we are saying up to which likely corresponds to an extreme case and something like 18 bytes seems reasonable. > > On the other hand, in IoT > communications, sending extra bytes can significantly impact the > battery life of devices and thus the life time of the device. The > document describes a framework that optimizes the networking overhead > associated to IPsec/ESP for these devices. > > > You say nothing about constrained comm links. This compression may make > ESP viable over links like LoRaWAN. > > yes. if that is not in the doc, it might be we said it too many times that we finally forgot ;-). > ESP Header Compression (EHC) chooses another form of context > agreement, which is similar to the one defined by Static Context > Header Compression (SCHC). > > Reference rfc 8724. > > And more than 'similar"? Maybe "based on the one"? > > currently not, but this is actually what we think we should do. > The context > itself can be negotiated during the key agreement, which allows only > minimal the changes to the actual ESP implementation. > > I don't get this. What only allows minimal changes? The key agreement > protocol or ECH? If the later then perhaps: > > no. whatever is used to describe the compression descripression will not be implemented by setting a compressor / decompressor for at least ESP software implementation. The changes are minor. On the other hand, things may be a bit more complex for hardware based ESP which cannot be modified. In that case, we probably need to implement the compression / decompression steps outside ESP. > The context > itself can be negotiated during the key agreement, which then needs > only > minimal the changes to the actual ESP implementation. > > More for introduction: > > Perhaps you can add that in transport mode, an SA may be for a single > transport/port to tune the ECH for that use and that multiple SAs could > be negotiated for this case. > > Question: Can a single IKE exchange produce multiple SAs? > > The context is per SA, so I suppos ethe suggestion is to make it per SA if that has not been clearly specified in the IKE extension document. > Here is my use case: > > Between the UA and GCS are two flows. One for Command and Control (C2) > the other streaming video. Both over UDP, but different ports. So > instead of having carry the UDP ports in all the messages, negotiate > separate SAs with the appropriate ECH. > > Ah, I see this in Sec 5. You should say something about this in the intro. > > sec 4. > > EHC is able to compress any protocol encapsulated in ESP and ESP > itself. > > No really true per other claims. Does it offer compressing RTP? I need > that, probably, for my streaming video app. > > We probably need to clarify this. It seems the baseline is pretty much any layer related to traffic selectors, which I think could theoretically be pretty high up in the layers though in practice this may be reduced to IP and transport. > to compress any IP and transport protocol... > > And only TCP and UDP are shown, what about, say, SCTP? > > BTW, I note that you use 'IKEv2'. At this point is that really needed? > Should just IKE be enough? Has not IKEv1 been depreicated? > could be. > > 6. EHC Context > > > The EHC Context is defined on a per-SA basis. A context can be > defined for any protocol encapsulated with ESP and for ESP itself. > > Should that be "any IP or Transport protocol"? To exclude layer 5 > protocols (CoAP, RTP,,,)? > > probably > Layer 5 protocols SHOULD be via standard SCHC with the SCHC Rule ID > included... > > I tend to agree. > Or maybe 'typically'? As some layer 5 might be easy? RTP maybe? > > So this is it for this round of comments. I am looking at Appdx A and > making a UDP example. Including IIV. > > Bob > > _______________________________________________ > IPsec mailing list > IPsec@ietf.org > https://www.ietf.org/mailman/listinfo/ipsec > -- Daniel Migault Ericsson
_______________________________________________ IPsec mailing list IPsec@ietf.org https://www.ietf.org/mailman/listinfo/ipsec
