From Jared:

I keep hear of Frame-Relay and ATM signaling that is going to happen in large providers MPLS cores. That's right, your "safe" TDM based services, will be transported over someones IP backbone first. This means if they don't protect their IP network, the TDM services could fail. These types of CES services are not just limited to Frame and ATM. (Did anyone with frame/atm/vpn services from Level3 experience the same outage?)

We use Level3 for IP transit and transport (both DS-3 and Ethernet over MPLS (via Martini)) all over the country. As with everyone else, we saw the problems with the transit traffic out of SJC and ATL. However, our transport services were not affected at all by the problems. In fact, I just ended up sending my Level3-SJC bound traffic to LAX via Level3 which was going through the same equipment as the transit traffic which was having problems.

From Pete:

From this, it can be deduced that reducing unneccessary system complexity and shortening the strings of pearls that make up the system contribute to better availablity and resiliency of the system. Diversity works both ways in this equation. It lessens the probablity of same failure hitting majority of your boxes but at the same time increases the knowledge needed to understand and maintain the whole system.

I would vote for the KISS principle if in doubt.

I agree. Granted the string of pearls is always going to be pretty long, but there are definitely is a trend from what I have seen with customers to make the string longer than it needs to be. -Sean Sean P. Crandall VP Engineering Operations MegaPath Networks Inc. 6691 Owens Drive Pleasanton, CA 94588 (925) 201-2530 (office) (925) 201-2550 (fax)