NAP/ISP Saturation WAS: Re: Exchanges that matter...

dave o'leary doleary at
Mon Dec 16 20:29:27 UTC 1996

At 2:52 PM -0500 12/16/96, Mike Leber wrote:
>On Sun, 15 Dec 1996, Forrest W. Christian wrote:
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>The loss is caused by atleast three things:
>* ICMP packets are dropped by busy routers
>Many routers drop ICMP packets (ping, traceroute) when busy, or alternate
>dropping ICMP packets.  I know that this behavior occurs when the packets
>are directed to the specific router, I am not sure if this every occurs
>for packets passing through.  The standby tool ping needs a more reliable
>replacement for testing end to end packet loss.

in general the router isn't going to treat one protocol (i.e. protocols
running over IP (TCP, UDP, ICMP) differently when the packets are passing
through the router - it just looks at the header and forwards.  ciscos do
handle pings for which the router itself is the destination at a lower
priority than packets going through the box.  I'll leave the discussions
as to whether ping is adequate or not for another time....

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