Re: New Version Notification for draft-bonica-6man-frag-deprecate-00.txt

[Mark Andrews <[e-mail]>]

In message <CAKr6gn2zu2n-pJMirG-seN5WX=[e-mail]>
, George Michaelson writes:
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> On Tue, Jun 25, 2013 at 2:38 AM, Ronald Bonica <[e-mail]> 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: [phone]                 INTERNET: [e-mail]