[183372] in North American Network Operators' Group
Re: PMTUD for IPv4 Multicast - How?
daemon@ATHENA.MIT.EDU (Masataka Ohta)
Mon Aug 31 21:21:29 2015
X-Original-To: nanog@nanog.org
Date: Tue, 01 Sep 2015 10:21:23 +0900
From: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>
To: Mark Andrews <marka@isc.org>
In-Reply-To: <20150901010533.6795D3687524@rock.dv.isc.org>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
Mark Andrews wrote:
>> Yes, it is. Generating an ICMP PTB is as burdensome as
>> fragmenting a packet.
>
> Well it could be done at wire speed.
Both of them could be.
> There is no theoretical reason
> why it has to be more burdensome than forwarding a packet.
That's not my point.
> The communiction fails.
It depends on layer 4 and above.
> Additionally routers normally rate limit
> PTB generation thereby reducing cpu loads to a acceptable level
> which is the whole point of moving the fragmentation to the originating
> node.
Routers can rate limit fragment generation, too.
Masataka Ohta
