nanog mailing list archives
Re: PMTUD for IPv4 Multicast - How?
From: William Herrin <bill () herrin us>
Date: Mon, 31 Aug 2015 16:38:36 -0400
On Mon, Aug 31, 2015 at 3:49 PM, <sthaug () nethelp no> wrote:
ICMP replies to multicast packets can cause ICMP "implosion". This is not a new discussion - see for instance http://mailman.nanog.org/pipermail/nanog/2012-June/048685.html
It's a shame we handle path MTU as a layer 3 problem that gets an ICMP response from a middlebox. It'd make more sense to truncate the packet, set a flag, and then let layer 4 at the recipient deal with negotiating a new size with the sender. You know, end to end principle and all. That'd eliminate the problems with firewall-blocked protocols and routers using private IP addresses, the usual culprits for pmtud breakage. It'd also let multicast protocols make reasonable choices for that particular protocol without being stuck with the stack's default. -Bill -- William Herrin ................ herrin () dirtside com bill () herrin us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>
Current thread:
- PMTUD for IPv4 Multicast - How? Chris Marget (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Valdis . Kletnieks (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Chris Marget (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? sthaug (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? William Herrin (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Masataka Ohta (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Chris Marget (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Chris Marget (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Masataka Ohta (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Chris Marget (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Masataka Ohta (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Chris Marget (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Valdis . Kletnieks (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? William Herrin (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Masataka Ohta (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Mark Andrews (Aug 31)
- Re: PMTUD for IPv4 Multicast - How? Masataka Ohta (Aug 31)