Re: [aqm] ping loss "considered harmful"

David Lang <david@lang.hm> Mon, 02 March 2015 20:40 UTC

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From: David Lang <david@lang.hm>
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Subject: Re: [aqm] ping loss "considered harmful"
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On Mon, 2 Mar 2015, Dave Dolson wrote:

> Would you do that to TCP or UDP traffic?
>
> At IETF I often hear laments about middle-boxes breaking the internet by being "clever" with certain types of traffic.
> It seems that policing ICMP falls into that category.
>
> There may have been bugs in the past, but I'm not aware that ICMP packets are any more dangerous than UDP or TCP. And if the RFCs can be believed, ICMPv6 is critical to determining Path-MTU. Don't drop those.
>
> One may wish to rate-limit ICMP (or DNS or TCP) flows as a matter of network policy, but in my opinion this should be kept orthogonal to solving buffer bloat.
>
> Taken to the extreme, a network should support full utilization of a link doing only ping. If I wish to use my connection to the internet to ping hosts at full line rate, why not?

what's going on here isn't that pings are being rate limited, but rather that 
the TCP/UDP traffic is being given priority over the ping traffic. This means 
that when you max out the pipe, pings will suffer.

David Lang