[Update] [Rumors]: Which IMS Component Caused Verizon's LTE Outage?

 
[Update]: Tekelec informed me that "Our Diameter Signaling Router was not responsible for the Verizon Wireless outage".

In a recent post to the Gigaom blog, Kevin Fitchard interviews Verizon Wireless VP of network engineering Mike Haberman, trying "to shed some light on the LTE network’s recent problems and explain how Verizon was taking the necessary steps to ensure that they don’t happen again" (see "Verizon explains its string of LTE outages" - here).

Haberman told Gigaom that "All three outages were caused by problems in Verizon’s service delivery core — in telecom-speak called the IP Multimedia Subsystem (IMS) .. The first outage on Dec. 7 was caused by the failure of a back-up communications database. The second, last week, was the result of an IMS element not responding properly, while Wednesday’s outage was caused by two IMS elements not communicating properly .. once each problem was fixed, it never recurred. Every subsequent outage is a result of a new bug, and it just so happens that December was the month many of these bugs chose to reveal themselves .. "

"Veizon’s IMS systems are a complex network of databases, servers, routers, gateways and policy managers supplied by multiple vendors. Alcatel-Lucent, Nokia Siemens Networks, Acme Packet and Tekelec all provide different parts, but Haberman declined to identify which particular elements or which particular vendors were responsible for the problems. In fact, Haberman defended Verizon’s vendors saying that they were experiencing the same LTE growing pains as Verizon".

A 2nd hand rumor I heard, claims that one of the IMS elements that failed this week was Tekelec's Diameter Signaling Router (DSR).

For background - see "How does/will Verizon Wireless Use Tekelec's Diameter Router?" - here.