Hi erik, If we compress IP in IP and a HbH header, we can hardly make that 0 bits overhead. The FL allows a total cost of 20 bits, whereas the compression will end up with 5 or 6 octets minimum...
Pascal > -----Original Message----- > From: Erik Nordmark [mailto:erik.nordm...@oracle.com] > Sent: Thursday, September 16, 2010 6:44 PM > To: Pascal Thubert (pthubert) > Cc: Philip Levis; Carsten Bormann; r...@ietf.org; ipv6@ietf.org; > m...@sandelman.ca; Brian E Carpenter > Subject: Re: [Roll] Flow Label: 12 bits mutable and 8 bits immutable > > On 09/16/10 05:07 AM, Pascal Thubert (pthubert) wrote: > > >> Has anybody discussed adding a header with just the 3 bytes you need > >> *before* the IP header? > > > > We've discussed using forms of tag switching from the beginning of the > > WG but there must be an IP based reference model before we start doing > > the tricks. > > You can have a reference model which uses IP-in-IP plus a destination options > to carry the 3 bytes, and then have an optimization for low speed networks like > 6lowpan that sticks those bytes somewhere else as Carsten suggested. > > Architecturally, in both cases, we'd end up with the 3 bytes before the > (inner) IP header. > > Erik -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
