Simon M. Leopold of Morgan Keegan & Company Inc. put out a research note Thursday afternoon that suggests that the daylong 4G outage was caused by a server that became unstable under heavy loads:
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Our checks indicate that a team from Verizon and its key vendors including Alcatel-Lucent (NYSE: ALU), Ericsson AB (Nasdaq: ERIC) and Nokia Siemens Networks (NSN) pulled together and came up with a work around over night. Our checks suggest the problem resides deep in the network core and involves difficulties authenticating devices as they attempt to connect to the network. We suspect the overload relates to the HSS, the Home Subscriber Service, which is part of the IP Multimedia Subsystem (IMS). We believe the IMS solution comes from NSN. The infrastructure from Alcatel-Lucent and Ericsson seem as if they are functioning properly.
Verizon Wireless had no comment when LR Mobile asked about the analyst note on Thursday.
— Dan Jones, Site Editor, Light Reading Mobile
The detail isn't there to know for sure, but given the Diameter signaling environment here, this could be a problem that a policy exchange controller (PEC) could solve. Many companies are introducing these new products (including my own) to secure and scale the Diameter signaling environment that is prevalent in LTE and IMS.
One role a PEC plays is load balancing, routing and performing admission control for Diameter, including in front of HSS and PCRF servers.