[96375] in North American Network Operators' Group
Re: barak-online.net icmp performance vs. traceroute/tcptraceroute,
daemon@ATHENA.MIT.EDU (Joe Maimon)
Sun May 6 21:08:25 2007
Date: Sun, 06 May 2007 21:07:17 -0400
From: Joe Maimon <jmaimon@ttec.com>
To: "Steven M. Bellovin" <smb@cs.columbia.edu>
Cc: Lincoln Dale <ltd@interlink.com.au>, "'nanog'" <nanog@merit.edu>
In-Reply-To: <20070507004723.9BCEE76667F@berkshire.machshav.com>
Errors-To: owner-nanog@merit.edu
>>
>>I did include icmp echo directly to each hop as a comparison.
>>
>
> Right, but from what you posted you didn't send 1500-byte packets. My
> reaction was the same as Lincoln's -- it smells like a Path MTU
> problem. To repeat -- ping and traceroute RTT from intermediate nodes
> is at best advisory, especially on timing.
>
> I should add -- DSL lines often use PPPoE, which in turn cuts the
> effective MTU available for user packets. If the PMTUD ICMP packets
> don't get through -- and they often don't, because of misconfigured
> firewalls -- you're likely to see problems like this.
>
Of course, and thats why I have cut down ip mtu and tcp adjust mss and
all the rest.
Not making much of a difference.
Furthermore, ipsec performance with normal sized icmp pings is what I
was referring to, and those are nowwhere near full-sized.
