Hi Joe, > -----Original Message----- > From: Joe Touch [mailto:[email protected]] > Sent: Tuesday, May 05, 2015 12:42 PM > To: Tom Herbert; Templin, Fred L > Cc: Xuxiaohu; Donald Eastlake; [email protected]; [email protected]; > [email protected]; [email protected] > Subject: Re: [trill] Fwd: Mail regarding draft-ietf-trill-over-ip > > > > On 5/5/2015 12:34 PM, Joe Touch wrote: > >> Or just define a simple version translation as part of encapsulation. > >> > So for IPv8: > >> > > >> > 0x1000->0x0101 on encapsulation > >> > 0x0101->0x1000 on decapsualtion > > And what happens to 0x0101 WHEN it shows up? > > > > You need more patterns than you have because IP is allowed to use any of > > them. > > FWIW, you're essentially arguing for bit-stuffing, i.e., if a pattern > you think will be common shows up, don't stuff, and if something else > shows up, then do. > > That works only if you do true stuffing, e.g.,: > > 0x01** = uncompressed > (might as well add 0x11** and 0x10** to that) > 0x00** = compressed > > But then if 0x0000, 0x0001, 0x0010 or 0x0011 show up, you need to decide > how to represent them - they CANNOT be uncompressed without at least two > more bits somewhere else that indicates they're uncompressed and their > value. > > So now your GUE methods are very sensitive to IP version numbers, which > IMO defeats the "G" in the name. Never mind how this complicates > hardware when (not if) other IP versions are used (for whatever reason).
No; it is still Generic. If the packet is not a direct-mapped IP packet, then there is a GUE header that can encapsulate any (foo) protocol. True that IP protocol versions that can be represented as 0xX1XX can be directly mapped while other (foo) protocols cannot does not mean that we should not take advantage of the direct mapping when possible. About h/w complications, the test is incorporated in the same test that hardware already uses to check the IP version number, i.e., no new instructions needed. Thanks - Fred [email protected] > Joe > > _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
