Re: Non-Last Small IPv6 Fragments

["Bjoern A. Zeeb" <[e-mail]>]

On 11 Jan 2019, at 3:02, Brian E Carpenter wrote:

Hi,

> If an RFC7195 translator receives an IPv4 fragment, it will translate 
> it into an IPv6 fragment. So if the IPv4 fragment is "small" by some 
> definition, so is the IPv6 fragment.
>
> I think that's a legitimate route to non-last fragments shorter than 
> 1280, regardless of what is considered normal for IPv6.

I think this topic has been re-hashed in the past often enough.

I want us to stop thinking that there’s anything but IPv6 if we ever 
want fragments to be “clean” and sorted and usable and working.  
It’s a total waste of time to sort this out for a transition 
technology as it’d be a major change to IPv6 implementations and 
involving end nodes and translator nodes (*) and by that time that would 
have happened IPv4 is no longer relevant.

Can we please start looking ahead to the decades of IPv6-only before we 
need to extend “real-time” communications to Mars and outside of our 
galaxy? (+)


/bz


(*) If you really wanted to you’d need a way to signal the min-MTU 
violation from the translator exception case to the end not and you’d 
probably need some kind of extension header for that.  Sadly this 
wasn’t done 20 years ago and neither for 8200.