> > I agree with the discussion here. > > For the sake of these drafts, how about we add brief discussion on the > following potential solutions: > -- applying ROHC segmentation > -- IP fragmenting packets post ROHC/IPsec processing > > Perhaps we simply document the benefits / considerations of these two > alternatives. Also, now that ROHC segmentation is possible, we will > also need to change some of the current wording (which specifies that > segmentation is not used) in the IKEv2 and IPsec drafts. >
I think this has issues for a specification that is intended to interoperate. One end point sends ROHC segmentation, the other end doesn't implement it => packet losses for all packet that attempts to use it. Relaying on IP fragmentation might work, but should probably make it clear that the tunnel egress MUST implement IP defragmentation to allow for this option. > If we wanted to open it up further, we could also look at the following > alternatives (however, these will deviate a bit more from what is > currently in these drafts): > --as Joe mentioned, if the ROHC packet exceeds the size of the MTU, just > transmit the uncompressed packet. However, the drawback here is that > ROHC is statefull compression algorithm... and we could run into > problems in terms of context state invalidation (e.g., if the copy of > the packet with no payload gets reordered or dropped in the unprotected > domain). > --inner fragmentation, where the packet is fragmented and then > subsequently handed to the ROHC-enabled SA for compression and IPsec > processing. However, AFAIK, I do not think that current ROHC profiles > can compresses packets/packet fragments (e.g., MF is STATIC-KNOWN, and > is always assumed to be 0), so such a solution could be a bit difficult > as well. My intention was not to redesign the world. Simply to take the issue into consideration and make it clear what should be done. Cheers Magnus Westerlund IETF Transport Area Director & TSVWG Chair ---------------------------------------------------------------------- Multimedia Technologies, Ericsson Research EAB/TVM ---------------------------------------------------------------------- Ericsson AB | Phone +46 10 7148287 Färögatan 6 | Mobile +46 73 0949079 SE-164 80 Stockholm, Sweden| mailto: [email protected] ----------------------------------------------------------------------
