Thoughts on increasing MTUs on the internet

Thu Apr 12 16:07:29 UTC 2007

On (2007-04-12 16:28 +0200), Iljitsch van Beijnum wrote:
> 
> On 12-apr-2007, at 16:04, Gian Constantine wrote:
> 
> >I agree. The throughput gains are small. You're talking about a  
> >difference between a 4% header overhead versus a 1% header overhead  
> >(for TCP).
> 
> 6% including ethernet overhead and assuming the very common TCP  
> timestamp option.

Out of curiosity how is this calculated?
[ytti at ytti.fi ~]% echo "1450/(1+7+6+6+2+1500+4+12)*100"|bc -l
94.27828348504551365400
[ytti at ytti.fi ~]% echo "8950/(1+7+6+6+2+9000+4+12)*100"|bc -l
99.02633325957070148200
[ytti at ytti.fi ~]% 

I calculated less than 5% from 1500 to 9000, with ethernet and
adding TCP timestamp. What did I miss?

Or compared without tcp timestamp and 1500 to 4470.
[ytti at ytti.fi ~]% echo "1460/(1+7+6+6+2+1500+4+12)*100"|bc -l
94.92847854356306892000
[ytti at ytti.fi ~]% echo "4410/(1+7+6+6+2+4470+4+12)*100"|bc -l
97.82608695652173913000

Less than 3%.

However, I don't think it's relevant if it's 1% or 10%, bigger
benefit would be to give 1500 end-to-end, even with eg. ipsec
to the office.

-- 
  ++ytti