Header overhead percentage is fairly useless alone. A real-world comparison would need take into account the speed of a given connection.
- Mark On Jul 25, 2011, at 5:59 AM, Rémi Després wrote: > > Wojciech, > > IPv4-header computations of draft-dec-stateless-4v6-02 are AFAIK too much in > favor of translation (4v6T) vs encapsulation (4V6E). > > The draft has: > +------------------------+--------------------+---------------------+ > | Item | 4V6 Translation | 4V6 Mapped Tunnel | > | | mode | Mode | > +------------------------+-------- ... -------+---------------------+ > | Overhead in relation | a) 0% b) 0% | a) 4.36% b) 1.71% | > | to average payload of | | | > | a) ~550 bytes b) 1400 | | | > | bytes). | | | > | ------------------ | ------------------ | ------------------ | > > An IPv4 packet having a 550 B payload is 570 B long (ignoring possible IPv4 > options): > - 4V6T adds 20 B (3.5 %). > - 4V6E adds 40 B, (7.0 %). > An IPv4 packet having a 1400 B payload is 1420 B long (at least) > - Translation adds 20/1420 = 1,4 % > - Encapsulation adds 40/1420 = 2,8 % > > This gives: > | ------------------ | ------------------ | ------------------ | > | Overhead in relation | a) 3.5% b) 1.4% | a) 7% b) 2.8% | > | to average payload of | | | > | a) ~550 bytes b) 1400 | | | > | bytes). | | | > | ------------------ | ------------------ | ------------------ | > > In addition, a complete comparison should take in consideration the length of > layer-2 headers, as well as that of the physical preambles if any. This leads > to even less different overhead ratios. > > Also, 4V6 devices can be expected to soon have an increasing part of their > traffic in IPv6. With this, the 4V6 overhead in % will soon decrease > accordingly. > > Conclusion: this line of the table deals with a difference that, although it > is real, is not significant compared to other considerations (e2e > transparency is one that deserves a separate discussion). > > Regards, > RD > _______________________________________________ > Softwires mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/softwires _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
