[nsp] load balancing over parallel DSL lines

Mark E. Mallett mem at mv.mv.com
Thu Nov 20 18:29:59 EST 2003

On Thu, Nov 20, 2003 at 05:15:36PM -0600, Parrish, Ben wrote:
> Mark E. Mallett wrote:
> >>   Load distribution: 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 (refcount 1)
> >
> >(etc)
> >
> >I was (erroneously, I guess) thinking that this was telling me that
> >packets were only taking one of the paths.  In the output above, the
> >"current path" note is only attached to one destination, and the
> >alterating 0s and 1s seemed to be confirming that only one
> >path was selected.  Can anyone enlighten me on the true meaning?  
> Mark, As I remember the hash used for CEF load-balancing has an output of 0
> to 7.  Thus the queues are numbered the same.  You have the two queses here
> that it is showing how it will distribute the load.  

Somebody else pointed that out to me, and it was like throwing a light
switch in my brain.  I had looked at the 0 1 0 1 sequence as a truth
table: false / true / false / true for a cyclic channel mapping.  It
never even occured to me that this was a list of channel numbers taken
by a sequence of packets.  Duh!

(I did attempt to find a detailed explanation of that output, but
to no avail.)

> (A packet for queue 0 and a packet then for queue 1, rinse, wash and
> repeat).  There was an email that went out with in the last week or so that
> talked a little about this with regards to load-balancing on a Catalyst.

Guess I should have read the Catalyst-related threads :-)

Thanks all,

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