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 have

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 which may

Re: Ipv6 addressing for Core network

2011-02-10 Thread Vikas Sharma
HI Geroge, Thanks for the input. Appreciate some more info wrt TCAM usuage if possible. Another thought, I agree ip schema is individual preference, but I want to know the best practise (vague term best practice). Personally even I am in favor of /64 p-t-p. Regards, Vikas On Wed, Feb 9, 2011 at

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: IPv6 addressing for core network

2011-02-09 Thread Iljitsch van Beijnum
On 9 feb 2011, at 5:24, Vikas Sharma wrote: I am looking for the recommendation for core interfaces IP addressing schema for Ipv6. Some different views are (PE- P - PE, point to point link) as below - Is there a NANOG FAQ we can add this to? 1- Use Public Ipv6 with /122 and do not

Re: IPv6 addressing for core network

2011-02-09 Thread sthaug
Is there a NANOG FAQ we can add this to? 1- Use Public Ipv6 with /122 and do not advertise to Internet 2- Use Public Ipv6 with /127 and do not advertise to Internet The all zeros address is the all routers anycast address so on most non-Cisco routers you can't use it, ruling out

Re: IPv6 addressing for core network

2011-02-09 Thread Iljitsch van Beijnum
On 9 feb 2011, at 10:48, sth...@nethelp.no wrote: The all zeros address is the all routers anycast address so on most non-Cisco routers you can't use it, ruling out /127. The top 128 addresses in any subnet are also reserved anycast addresses although they don't do much in practice. So the

Re: IPv6 addressing for core network

2011-02-09 Thread sthaug
A /127 mask is still the best way to handle real point-to-point links like SDH/SONET today, to avoid the ping-pong problem. Works fine with Cisco and Juniper, not tried with other vendors. I know it's immature, but I can't wait for some new hire at vendor C or vendor J to reread the

Re: IPv6 addressing for core network

2011-02-09 Thread Mohacsi Janos
On Wed, 9 Feb 2011, sth...@nethelp.no wrote: A /127 mask is still the best way to handle real point-to-point links like SDH/SONET today, to avoid the ping-pong problem. Works fine with Cisco and Juniper, not tried with other vendors. I know it's immature, but I can't wait for some new hire

Re: IPv6 addressing for core network

2011-02-09 Thread sthaug
Global scope addresses on router-to-router interfaces are necessary today for traceroute to work. Some ISPs are *requiring* working traceroute (without MPLS hiding of intermediate hops) in RFPs to transit providers. If you can get router ICMP handling changed such that the ICMP packet

Re: IPv6 addressing for core network

2011-02-09 Thread Iljitsch van Beijnum
On 9 feb 2011, at 11:16, sth...@nethelp.no wrote: If you can get router ICMP handling changed such that the ICMP packet generated by traceroute is sent from the loopback address, we might be able to do without global scope addresses on router-to-router interfaces. But until then... I'm

Re: IPv6 addressing for core network

2011-02-09 Thread Sam Stickland
On 9 Feb 2011, at 09:48, sth...@nethelp.no wrote: Is there a NANOG FAQ we can add this to? 1- Use Public Ipv6 with /122 and do not advertise to Internet 2- Use Public Ipv6 with /127 and do not advertise to Internet The all zeros address is the all routers anycast address so on most

Re: IPv6 addressing for core network

2011-02-09 Thread sthaug
A /127 mask is still the best way to handle real point-to-point links like SDH/SONET today, to avoid the ping-pong problem. Works fine with Cisco and Juniper, not tried with other vendors. Can you elaborate on this? What's the ping-pong problem? This has been well covered in the

Re: IPv6 addressing for core network

2011-02-09 Thread David Freedman
I think the solution to all of these problems is really to use public addressing but filter access to it at your edge (yes, even ICMP TOOBIG can be filtered safely if you have designed things in a sane way) Dave. -- David Freedman Group Network Engineering Claranet Group

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

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 can still

Re: IPv6 addressing for core network

2011-02-09 Thread Owen DeLong
On Feb 9, 2011, at 9:30 AM, David Freedman wrote: I think the solution to all of these problems is really to use public addressing but filter access to it at your edge (yes, even ICMP TOOBIG can be filtered safely if you have designed things in a sane way) Filtering ICMP TOOBIG is actually

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 so you'd think path

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,

Ipv6 addressing for Core network

2011-02-08 Thread Vikas Sharma
Hi, I am looking for the recommendation for core interfaces IP addressing schema for Ipv6. Some different views are (PE- P - PE, point to point link) as below - 1- Use Public Ipv6 with /122 and do not advertise to Internet 2- Use Public Ipv6 with /127 and do not advertise to Internet 3- Use

RE: Ipv6 addressing for Core network

2011-02-08 Thread George Bonser
I am looking for the recommendation for core interfaces IP addressing schema for Ipv6. Some different views are (PE- P - PE, point to point link) as below - 1- Use Public Ipv6 with /122 and do not advertise to Internet 2- Use Public Ipv6 with /127 and do not advertise to Internet 3-

Re: Ipv6 addressing for Core network

2011-02-08 Thread Jimmy Hess
On Tue, Feb 8, 2011 at 10:24 PM, Vikas Sharma vikasshar...@gmail.com wrote: Hi, I am looking for the recommendation for core interfaces IP addressing schema for Ipv6. Some different views are (PE- P - PE, point to point link) as below - 1-  Use Public Ipv6 with /122 and do not advertise to