Initial Route Server Stats for MAE-East

Jeff Young young at mci.net
Mon Oct 23 01:04:19 UTC 1995


by all means, ping all you like.  please do realize that 
routers have other things to do besides answer pings when
they're busy.  just because a router doesn't respond to 
15% of its pings doesn't mean that it's dropping 15% of
its packets or that there is a 15% loss on a line.  router
load is not router load, process switched packets are not
the same as card-level switched or cache switched.

there aren't any easy answers.  perhaps we should all just
implement "ping" servers in pops ( a 386 running
linux or bsd might suffice).

Jeff Young
young at mci.net

> 
> > 
> > On Sat, 21 Oct 1995, Mike O'Dell wrote:
> > 
> > > remember that using pings to sample connectivity to a very busy
> > > cisco router is not a very reliable probe for several reasons.
> > > Returning pings is a low-priority task in the first place, and
> > > they are rate-limited, so if the processor is busy processing
> > > lots of BGP updates and several folks are fribbling with it 
> > > using ping or SNMP, it is less than clear what they will see.
> > > 
> > > 	-mo
> > 
> 
>  Michael A. Nasto quips:
> 
> > OK!  Agreed.  So then, what would you use? 
> > 
> 
> Have you ever been in a classroom and had a student raise his hand,
> answer every question, ask intelligent questions, etc. just to prove
> to the class how smart he or she is.    This is the premise of
> the 'Two Mike's Interchange' above.  One says, HEY!  I know ping packets
> are a lower priority than everything else in a *CISCO* router 
> LOOK AT ME (wave wave). Then another kid in the class quips...
> if PING is not what you would use, give us a better utility.
> 
> In fact... EVERYONE ( okay 99.73 percent :-) uses PING.  After all 
> router LOAD is router LOAD.... and if a few ICMP packets can't get 
> back in a subjectly reasonable time.. then DUH.... "da network
> is busy......"  BGP updates take bandwidth just like any other packet.
> 
> Of course the 0.27 percent, zen routing gods of the universe just
> feel the load and the harmonic BGP update patterns and PING between
> the BGP updates.... for a better answer.
> 
> Sorry, I could not resist.... and apologize for the satire.  PING!!
> PING!! PING!!
> 
> Tim
> 
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