comcast routing issue question

Thu Nov 30 06:23:41 UTC 2006

On Thu, Nov 30, 2006 at 12:28:30AM -0500, Jim Popovitch wrote:
> 
> On Thu, 2006-11-30 at 00:06 -0500, Jim Popovitch wrote:
> > Question:  What could cause the first trace below to succeed, but the
> > second trace to fail?
> > 
[snip]
> > Taking the 69.61.40.33/28 subnet a bit further, .36 drops at 68.86.84.70
> > but .37 - .39 make it.  .40 drops at 68.86.84.70, but .41 makes it.
> > 
> > Crazy.
> 
> Btw, the problem has now been resolved, however I'm still curious as to
> what scenario could have caused that.

Perhaps CEF-style load balancing over multiple paths, with one of them
down and not properly failing over?  Per-flow balancing would decide
which path to use based on source & target IP.

> -Jim P.
> 

-- 
Jordan.