Re: Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-10 Thread Valdis . Kletnieks
On Thu, 10 Feb 2011 12:15:52 GMT, David Freedman said: > these people are doing this by design, I think thats the point I'm > trying to get across, if you will never need to process TOOBIG in your > design, there is no need to accept it. And how many networks break PMTUD because their design says

Re: Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-10 Thread David Freedman
Iljitsch van Beijnum wrote: > On 10 feb 2011, at 0:26, David Freedman wrote: > >>> Unless every packet you emit is ≤ the minimum MTU (1280), then, you need >>> to be able to receive TOOBIG messages. > >> Can you think of a packet type I will emit from my publically numbered >> backbone interface

Re: Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-10 Thread Iljitsch van Beijnum
On 10 feb 2011, at 0:26, David Freedman wrote: >> Unless every packet you emit is ≤ the minimum MTU (1280), then, you need >> to be able to receive TOOBIG messages. > Can you think of a packet type I will emit from my publically numbered > backbone interface which may solicit a TOOBIG that I'll h

Re: Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-09 Thread David Freedman
> Unless every packet you emit is ¾ the minimum MTU (1280), then, you need > to be able to receive TOOBIG messages. Can you think of a packet type I will emit from my publically numbered backbone interface which may solicit a TOOBIG that I'll have to care about? I can only think of three cases,

Re: Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-09 Thread Owen DeLong
On Feb 9, 2011, at 9:50 AM, David Freedman wrote: > Iljitsch van Beijnum wrote: >> On 9 feb 2011, at 18:30, David Freedman wrote: >> >>> (yes, even ICMP TOOBIG >>> can be filtered safely if you have designed things in a sane way) >> >> NO. >> >> Even if you run with 1280-byte MTUs everywhere s

Re: Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-09 Thread David Freedman
Iljitsch van Beijnum wrote: > On 9 feb 2011, at 18:30, David Freedman wrote: > >> (yes, even ICMP TOOBIG >> can be filtered safely if you have designed things in a sane way) > > NO. > > Even if you run with 1280-byte MTUs everywhere so you'd think path MTU > discovery wouldn't be needed, this c

Too bigs are sacred, was: Re: IPv6 addressing for core network

2011-02-09 Thread Iljitsch van Beijnum
On 9 feb 2011, at 18:30, David Freedman wrote: > (yes, even ICMP TOOBIG > can be filtered safely if you have designed things in a sane way) NO. Even if you run with 1280-byte MTUs everywhere so you'd think path MTU discovery wouldn't be needed, this can still cause problems with IPv6-to-IPv4 t