option 212 for 6RD

[Sam Wilson]

On 16 Jan 2013, at 03:49, Lorenzo Colitti wrote:

>
>
>
> On Tue, Jan 15, 2013 at 5:06 PM, Jeroen Massar <jeroen at massar.ch>  
> wrote:
> > Client <-> 6RD CPE <-> 6RD ISP RELAY <-> Web server
> >       < 1ms       <few ms>         <150 ms>
> >
> > Now, client sends SYN with high MSS, gets SYN+ACK back, sends,  
> ACK, send
> > GET request, web server sends first 1500 byte packet, 6RD ISP  
> RELAY has
> > to send back PTB to web server, web server sends new packet with  
> 1480
> > instead of 1500 byte size. Now you've lost one complete RTT  
> between 6RD
> > ISP RELAY and Web server.
>
> That is the way it is. The only way to get around that is the either
> lower the MSS or to remove your low MTU link.
>
> No, there's another way to get around it: lower the LAN MTU so the  
> host lowers the MSS itself.
> [snip...]

The solution is to mandate the same MTU on every link.  I'm not  
serious about that but it looks like the obvious direction that one  
side of this argument is going.

Sam

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