nanog mailing list archives
Re: IPv6 day and tunnels
From: Masataka Ohta <mohta () necom830 hpcl titech ac jp>
Date: Mon, 04 Jun 2012 14:41:03 +0900
Joe Maimon wrote:
So IPv6 fixes the fragmentation and MTU issues of IPv4 by how exactly?
Completely wrongly.
Or was the fix incorporating the breakage into the basic design?
Yes. Because IPv6 requires ICMP packet too big generated against multicast, it is designed to cause ICMP implosions, which means ISPs must filter ICMP packet too big at least against multicast packets and, as distinguishing them from unicast ones is not very easy, often against unicast ones. For further details, see my presentation at APNIC32: http://meetings.apnic.net/32/program/apops How Path MTU Discovery Doesn't work Masataka Ohta
In IPv4 I can make tunneling just work nearly all of the time. So I have to munge a tcp mss header, or clear a df-bit, or fragment the encapsulated packet when all else fails, but at least the tools are there. And on the host, /proc/sys/net
FYI, IETF is trying to inhibit clearing DF bit explicitly with draft-ietf-intarea-ipv4-id-update-05.txt >> IPv4 datagram transit devices MUST NOT clear the DF bit. which is now under the last call. Masataka Ohta
Current thread:
- RE: IPv6 day and tunnels, (continued)
- RE: IPv6 day and tunnels Templin, Fred L (Jun 12)
- Re: IPv6 day and tunnels Masataka Ohta (Jun 19)
- RE: IPv6 day and tunnels Templin, Fred L (Jun 19)
- Re: IPv6 day and tunnels Joe Maimon (Jun 04)
- Re: IPv6 day and tunnels Cameron Byrne (Jun 04)
- Re: IPv6 day and tunnels bmanning (Jun 03)
- Re: IPv6 day and tunnels Jeroen Massar (Jun 03)
- Re: IPv6 day and tunnels Jeroen Massar (Jun 03)
- Re: IPv6 day and tunnels Masataka Ohta (Jun 04)
- Re: IPv6 day and tunnels Jeroen Massar (Jun 04)
- Re: IPv6 day and tunnels Jared Mauch (Jun 04)
- Re: IPv6 day and tunnels Jeroen Massar (Jun 04)
- Re: IPv6 day and tunnels Joe Maimon (Jun 04)
- RE: IPv6 day and tunnels Templin, Fred L (Jun 04)
- Re: IPv6 day and tunnels Jeroen Massar (Jun 04)
- RE: IPv6 day and tunnels Templin, Fred L (Jun 04)
- Re: IPv6 day and tunnels Jeroen Massar (Jun 04)