Test your connectivity for World IPv6 Day
nanog at 85d5b20a518b8f6864949bd940457dc124746ddc.nosense.org
Tue Jun 7 14:33:10 CEST 2011
On Tue, 07 Jun 2011 08:07:13 -0400
Marc Blanchet <marc.blanchet at viagenie.ca> wrote:
> Le 11-06-07 07:55, Rémi Després a écrit :
> > Le 7 juin 2011 à 13:26, Marc Blanchet a écrit :
> >> Le 11-06-07 07:03, Mohacsi Janos a écrit :
> >>> Dear All,
> >>> A possible option would be for develop a new opportunistic PMTUD standard:
> >>> - start from 1280 and increase it until it is possible....
> >> see RFC4821.
> > Agreed.
> > However, RFC 4821 isn't completely clear as to which PMTU to try first.
> I've heard that it is already implemented on linux. don't know the
> details yet.
tcp_mtu_probing - INTEGER
Controls TCP Packetization-Layer Path MTU Discovery. Takes three
0 - Disabled
1 - Disabled by default, enabled when an ICMP black hole detected
2 - Always enabled, use initial MSS of tcp_base_mss.
> > As detailed in my last answer to Fred, 1280 seems the best choice, at least in IPv6.
> > Can we agree on this?
> nooo! IPv4 typical MTU is 1500. you are suggesting downgrading IPv6
> performance (compared to IPv4) by doing MTU 1280? does not make sense to
> me. PMTUd issues are the exception, not the problem. But the level of
> exceptions are higher now than it shall be later, since we are really
> deploying IPv6 now, removing old stuff, fixing as we go.
> Think also about backbone nodes/high-end servers that are able to do 9K
> MTU. Change to 1280 MTU. no.
> IETF81 Quebec city: http://ietf81.ca
> IPv6 book: Migrating to IPv6, Wiley. http://www.ipv6book.ca
> Stun/Turn server for VoIP NAT-FW traversal: http://numb.viagenie.ca
> DTN Implementation: http://postellation.viagenie.ca
> NAT64-DNS64 Opensource: http://ecdysis.viagenie.ca
> Space Assigned Number Authority: http://sanaregistry.org
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