MAE West

Fri Jul 11 17:17:55 UTC 1997

On Fri, 11 Jul 1997, Rodney Joffe wrote:

> By the way, to expand the thread, I have the feeling that the three
> OC-3s from NASA Ames side to MFS all go to GIGA 1, which then has fddi
> loops to GIGA 2 and then to GIGA 3.
> 
> Does anyone know if this is the case?
> 
> If it is, seems that a better design would have been to route some of
> the OC-3s to the other GIGAs first. If 1 is down, then it can't pass
> traffic through to 2 and 3, so there is a single point of failure for
> all the switches at MFS.

The Gigaswitch constrains us to a loop-free topology, so there's no way to
avoid a single point of failure in a case like this.

The Gigaswitch systems in general have been quite reliable over the last
few years, modulo individual line card failures.  The problems we tend to
see are either load-related or caused by human error.  This is the first
major outage caused by a Gigaswitch itself that we've seen in a very
long time.

By the way, as of yesterday it's four OC3's between Ames and MFS.
	Steve