Hi Ole, This kind of table you have below is IMHO the tool we need at this stage :-).
It has however to be more detailed: so far, it covers 4rd-H (the header-mapping variant of the last 4rd-U), but not 4rd-E (its encapsulation variant). A 4 columns table would be ideal. Also, It could have a sign identifying points that are N in current drafts, but could easily become Y if the final consensus is that they are worth the additional complexity. I can work on it if you are interested. More specific points below. They can be discussed one by one. Le 2012-02-02 à 11:12, Ole Trøan a écrit : >> More over, 4rd-U claims to solves a number of issues that the MAP suite of >> documents does not address. It would be beneficial to have >> a discussion on the mailing list to see if a) those issues are important or >> not and b), if they are, are they properties of 4rd-U or could they be >> solved as well >> in MAP, they just have not been addressed there yet. > > here is a comparison table of the feature differences between MAP and 4rd-U. > (try a fixed width font if it doesn't survive your particular MUA mail > mangling algorithm.) > > Appendix A. Comparions of stateless A+P solutions > > +-------------------------------+----------------+------------------+ > | Feature | MAP | 4rd-U | > +-------------------------------+----------------+------------------+ > | Encapsulation | Y | Y | > | Translation | Y | Y | > | Hub and Spoke mode | Y | Y | > | Nested CPE | N | Y | > | End-user prefixes > 64 | Y | N | (1)It is AFAIK also a "Y" for 4rd. (Not sure to understand the point.) > | E-mode: Support for IPv4 | Y | N | > | options | | | (2) 4rd-U draft 03 has excluded IPv4 options for both 4rd-H and 4rd-E but, for 4rd-E, they can easily be put back if found useful. (My vote is NO, but a WG consensus on YES for 4rd-E would not be a problem at all). > | T-mode: MF bit and TOS bits | N | Y | > | transparency | | | > | T-mode: Checksum | L4 rewrite | CNP | (3) The functional point is guaranteeing IPv4-payload preservation, with compatibility with ALL protocols using TCP-like checksum, present of future, with checksums anywhere in the payload. > | H & S set bit 79 needed | N | Y | (4) The functional point is to permit use cases like that of 5.3 of the last 4rd-U draft. The added complexity for this is close to nil, and applies ONLY to H&S scenarios. If abandoned (which is easy), it should be with due WG consciousness of which use cases are thus abandoned. > | Interface-id | RFC6052 | V octet | > | MAP traffic identified by | Address/prefix | Interception of | > | | | V octet | (5) The main functional point of the V octet is to avoid interfering with subnet assignments in customer sites. (6) Not sure to understand what you mean by "Interception of V octet". IPv6 routing within CEs or BRs is sufficient to orient IPv6 packets to the 4rd function. > | Port mapping algorithm | GMA. Prog. | GMA. Fixed | (7) Substantial complexity added for GMA isn't justified, in my understanding, by real use cases that would need it. This could easily be added to 4rd-U if so decides the WG (a waste IMHO). > | Fragment forwarding on BR | N | Y | > | without reassembly | | | > | Shared fragmentation id space | N | Y | > | BR rewrite fragmentation | N | Y | > | MSS update | Y | N | (8) I found no reference to MSS in MAP-E, and no reference to MSS update in MAP-T. Did I miss them? > | Complete IPv6 address / | Y | N | > | prefix | | | (9) Not sure what you mean by a complete IPv6 prefix. I see no functional limitation of 4rd-U with prefix lengths. > | Provisioned with DHCP | Y | Y | > +-------------------------------+----------------+------------------+ > > Table 1: A+P comparison Cheers, RD > > let us make it clear that these two solutions are solving exactly the same > problem, and they solve it in the same fundamental way (A+P). the differences > we're talking about here are what whistles, bells (and dongs) we want to add > on to the base specification. consider it a buffet, any feature from one of > them can be applied to the other. > > cheers, > Ole > _______________________________________________ > Softwires mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/softwires _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
