On Wed, 1 Aug 2001, Chris Wedgwood wrote:
> On Tue, Jul 31, 2001 at 10:12:12PM +0300, Pekka Savola wrote:
>
> Me neither. It would make 'ping -f' testing of your ISP's
> connections rather inconvenient ;-) ...
>
> As someone who until recently was involved in architecture and
> planning for a large ISP/carrier who's network spanned 3 continents (I
> just like saying that, it sounds better than it really is!) I can
> tell you plenty of people use similar tests.
>
> They are bogus. As is traceroute.
>
> ping & traceroute are very useful, but there results can often be
> misleading.
>
> For example, cisco routers, of which sadly there are a few still in
> use, do no respond to ICMP packets terribly reliably when they are
> busy, which is pretty reasonable (the route packets instead).
Who said I was pinging Cisco routers? If I have two servers 100 ms off
each other, I make them 'ping -f' each other. This does test the
infrastructure and forwarding capabilities a bit.
Traceroute isn't optimal as you noted, as the routers have to pull
the packet with expiring TTL off the "fast path", and this is often
subject to the rate-limiting considerations also.
--
Pekka Savola "Tell me of difficulties surmounted,
Netcore Oy not those you stumble over and fall"
Systems. Networks. Security. -- Robert Jordan: A Crown of Swords
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