[183369] in North American Network Operators' Group
Re: PMTUD for IPv4 Multicast - How?
daemon@ATHENA.MIT.EDU (Masataka Ohta)
Mon Aug 31 20:55:12 2015
X-Original-To: nanog@nanog.org
Date: Tue, 01 Sep 2015 09:55:06 +0900
From: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>
To: Chris Marget <chris@marget.com>
In-Reply-To: <CAAG5dDDv7k7L4JvmL_Zvd7jMD3T8AGERRE5V=mFJ7ySKh9S+6A@mail.gmail.com>
Cc: "nanog@nanog.org list" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
Chris Marget wrote:
>>> I'll probably come around, but I've not yet concluded that "screw it,
>>> fragment my traffic, I don't care" is the stance that a conscientious
>>> application should be taking.
>>
>> Don't you care, for routers, generating ICMP PTB is as burdensome
>> as generating fragments?
>
> I don't think so. If PMTUD is working (big IF, I know),
Yup.
> the ICMP PTB
> generation is a one-time thing (or once per 10 minutes or whatever)
A meaningful interval of retry is not 10 minutes but RTT measured
at layer 4 or above.
> Is the concern that I might DDoS myself
Or, with spoofed source addresses, someone else.
Masataka Ohta
