 |
 |
As of 2:00 pm, Merit reports that service has been restored, but there are still problems on the Extreme Aspen switches. One of the redundant network links between Michigan State University and Wayne State University has been disabled until repairs are made, but service should remain stable. Doug ----- Forwarded message from Doug Nelson <[log in to unmask]> ----- Date: Tue, 21 Aug 2007 12:52:20 -0400 From: Doug Nelson <[log in to unmask]> Subject: Re: [MSUNAG] Merit about yesterday's trouble To: [log in to unmask] For those of you who didn't attend Merit's web conference, here's a short update. Merit engineers traced the source of the Merit Network problems to the failure of an optical amplifier within the MiLR network, following scheduled maintenance by the fiber carrier. This failure created a marginal optical fiber path, and accounted for the network difficulties seen in the original outages between Thursday and Sunday, and again this morning, after a second scheduled fiber maintenance window. The fiber path failure was compounded by a software failure which repeatedly attempted to bypass the marginal link, and then rapidly restore the link to service. This process also caused the errant switches to exhaust their memory due to a second software failure, leading to additional packet switching and routing failures, cascading throughout the Merit Network. Once the problematic link was disabled, service returned to a somewhat stable state, but on limited bandwidth. As of 12:00 noon today, the Merit network appears to be operating normally and at full capacity, but we are awaiting final word from the Merit field and operations engineers on what was done and whether service is fully restored. I will pass on additional details once Merit releases them. Doug -- Doug Nelson, Network Manager | [log in to unmask] Academic Computing and Network Services | Ph: (517) 353-2980 Michigan State University | http://www.msu.edu/~nelson/ ----- End forwarded message ----- -- Doug Nelson, Network Manager | [log in to unmask] Academic Computing and Network Services | Ph: (517) 353-2980 Michigan State University | http://www.msu.edu/~nelson/