Hi Mark,

Thanks for this good empirical data!

I would like to verify your assertion that most of the IPv6 fragment carry UDP. 
Do you have any way to be sure?

                                      Ron


> -----Original Message-----
> From: Mark Andrews [mailto:ma...@isc.org]
> Sent: Monday, June 24, 2013 9:53 PM
> To: George Michaelson
> Cc: Ronald Bonica; ipv6@ietf.org 6man-wg
> Subject: Re: New Version Notification for draft-bonica-6man-frag-
> deprecate-00.txt
> 
> 
> In message <CAKr6gn2zu2n-pJMirG-seN5WX=Evyquu9EqqLOV-zf-
> rkq9...@mail.gmail.com>
> , George Michaelson writes:
> > --===============4023034923616370839==
> > Content-Type: multipart/alternative;
> > boundary=047d7b86e55011538004dff06308
> >
> > --047d7b86e55011538004dff06308
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > On Tue, Jun 25, 2013 at 2:38 AM, Ronald Bonica <rbon...@juniper.net>
> wrote:
> >
> > >    ** **
> > >
> > > I'd like to understand the basis of these assertions. I believe
> what
> > > I am seeing, on the edge, suggests there is in fact V6
> fragmentation
> > > in both TCP and UDP.****
> > >
> > > ** **
> > >
> > > ** **
> > >
> > > Hi George,****
> > >
> > > ** **
> > >
> > > It would be helpful if you could describe:****
> > >
> > > ** **
> > >
> > > **-          **Where your observations are being made
> > >
> >
> > On our own web services (www.apnic.net, and an associated whois
> > service which attracts more wide ranging traffic)
> >
> > On 'high in the tree' DNS servers for reverse DNS, including an NS of
> > in-addr.arpa and ip6.arpa (note: dns transport is disjoint from the
> > namespace being searched: we see queries over v6 transport to v4
> > domains, and to ccTLD we secondary)
> >
> > In a packet capture of 2400::/12 run in conjunction with Merit, as
> > research into darknets.
> >
> >
> > > ****
> > >
> > > **-          **What percentage of traffic is fragmented
> > >
> >
> > our own web: practically none.
> >
> > our own dns: 0.01%. in a sequence of 10 minute samples. consistently,
> > I might add.
> >
> > the 2400::/12:  around 0.25% to 1%. so more variable, but higher.
> >
> >
> > > ****
> > >
> > > **-          **What kinds of packets are being fragmented
> > >
> >
> > our own DNS: port 53. little TCP.
> >
> > 2400::/12 capture. mostly port 53. TCP doesn't get captured in the
> > darknet research. Its impossible to establish the end-to-end
> relationship.
> >
> > I am not sure I call up to 1% of something 'rare'. I'm not even sure
> I
> > call 0.1% or 0.01% of something 'rare'. Otherwise, Since IPv6
> adoption
> > rates are at this class of deployment by end user, perhaps it also
> > should be considered for deprecation..
> >
> > It really would be helpful to understand your assertion about the
> > rarity of
> > IPv6 fragmentation. I want to understand how you got to this point of
> > view on IPv6 frags.
> >
> > -George
> 
> .58% of my IPv6 traffic in fragmented.  Assuming that it is mostly UDP
> I get 14% of my IPv6 UDP traffic is fragmented.  Most of that traffic
> is non local.  I would assume most of the drops are due to PMTUD
> blocking the initial fragment but letting the tail fragment through as
> this machine is behind a tunnel.
> 
> Mark
> 
> ip6:
>       381915 total packets received
>       0 with size smaller than minimum
>       0 with data size < data length
>       0 with bad options
>       0 with incorrect version number
>       2213 fragments received
>       0 fragments dropped (dup or out of space)
>       48 fragments dropped after timeout
>       0 fragments that exceeded limit
>       1077 packets reassembled ok
>       217810 packets for this host
>       0 packets forwarded
>       93958 packets not forwardable
>       0 redirects sent
>       297719 packets sent from this host
>       0 packets sent with fabricated ip header
>       0 output packets dropped due to no bufs, etc.
>       5031 output packets discarded due to no route
>       33 output datagrams fragmented
>       66 fragments created
>       0 datagrams that can't be fragmented
>       0 packets that violated scope rules
>       93924 multicast packets which we don't join
>       Input histogram:
>               hop by hop: 132
>               TCP: 202894
>               UDP: 15103
>               fragment: 2213
>               ICMP6: 161573
> 
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: ma...@isc.org
> 



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