We definitely used to have this problem. Haven't noticed it in forever, but we also almost never have an EPC reset event either, ungraceful or otherwise. (Although it should be noted that I seem to recall that this could happen if the S1/MME session between a Compact and the EPC was interrupted, say because of a network partition event...anything that would make the EPC "go away" from the perspective of the Compact.)
Another somewhat related (?) problem we experienced (long ago) is that sometimes UEs would drop off for whatever reason, and take exactly 54 minutes to come back (if they did come back) unless the UE was rebooted before 54 minutes were up. Nick was able to figure this out: turns out that timer T3412 defaults to 54 minutes per the spec (http://www.lteandbeyond.com/2013/09/lte-emm-eps-mobility-management-timers.html). He had us shrink that down to 5 minutes with "set MME nas timer3412 5" on the EPC. Perhaps reducing that timer value down also made UEs more likely to recover than not whenever the EPC briefly vanished, which is why we haven't seen this issue in forever? -- Nathan From: [email protected] [mailto:[email protected]] On Behalf Of Shayne Lebrun Sent: Friday, November 18, 2016 11:15 AM To: [email protected] Subject: Re: [Telrad] Stuck UEs after ungraceful EPC loss We’ve seen this issue since we originally installed. Currently on EPC 0606.01004 and eNB 0606.04483. UE versions ranging from .77 to .105. From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Justin Davis Sent: Friday, November 11, 2016 11:19 AM To: [email protected]<mailto:[email protected]> Subject: Re: [Telrad] Stuck UEs after ungraceful EPC loss We have never seen that. But it could also be that we never loose power to them and they only reset when we tell them to. I would be curious though to see if we would experience the same issue in the event that both battery and generator failed. Are you running the latest release on the EPC? On Fri, Nov 11, 2016 at 8:08 AM, Shayne Lebrun <[email protected]<mailto:[email protected]>> wrote: Is anybody else still seeing the phenomena where, if the EPC goes away ‘ungracefully,’ say by losing power, rather than being ‘request reset reset’ed, that UEs often don’t reattach without a power cycle? We’ve seen it on every firmware version so far, including 105. _______________________________________________ Telrad mailing list [email protected]<mailto:[email protected]> http://lists.wispa.org/mailman/listinfo/telrad -- Sincerely, Justin Davis SkyWerx COO 970-731-9790
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