MAE West

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1

> 2) assuming that costs favored having both aggregates in service, if
> utilization on the two aggregates was 50% on (call it) A and 100% on B,
> the 50% available on A would be wasted. Note that latency would go up,
> because spanning tree would have pruned some intra-building link would
> have been pruned in order to keep the inter-building link active.

If this is true, then the Layer 2 bandwidth aggregation design is
pretty weak, no?

You're mixing apples and oranges.

For example, (and yes, I know there's a world of difference) a MLPPP
link is at (effectively) layer 2 (if not 1.5), and if one side of the
link drops, the other side will carry what it can.

That is what happens within an aggregate. The multi-link PPP channel
corresponds to an "aggregate" in the terminology that I am using.

The topic being discussed is not what happens within an aggregate, but
what happens when two aggregates are using. This would be akin to
having two multi-link PPP connections (each constructed out of some
number of physical links).

Stephen

2

> For example, (and yes, I know there's a world of difference) a MLPPP
> link is at (effectively) layer 2 (if not 1.5), and if one side of the
> link drops, the other side will carry what it can.

That is what happens within an aggregate. The multi-link PPP channel
corresponds to an "aggregate" in the terminology that I am using.

Ok. Got that.

The topic being discussed is not what happens within an aggregate, but
what happens when two aggregates are using. This would be akin to
having two multi-link PPP connections (each constructed out of some
number of physical links).

Ok, then a fair description of the problem is that "circuits cannot be
aggregated across multiple switch chassis". And that's not, in and of
itself, bad component design.

However, it pretty apparently limits the ability to make the best use
of your circuits in your system design...

or Mae West wouldn't have taken last Friday morning off.

Cheers,
-- jra