[EAS] CAP Polling Interval Questions

[ed.czarnecki at monroe-electronics.com]

Alex - I think 1 minute could be used as a minimum or baseline, but running the risk of delaying the alert by nearly a minute if the CAP EAS unit polled the server just a second before the new alert was posted.  20-30 seconds would probably be a reasonable compromise.  The DASDEC can poll in much smaller increments, but I think you get to a point of diminishing returns at some level. 

I'd expect (hope) that the IPAWS server(s) can handle a relatively limited universe of roughly 31,000 CAP EAS units (clients) polling every 30-60 secs.  That's one of the reasons I'm asking about the projected feed size and frequency of updates, the help estimate a maximum.

Regarding the question of Federal and state servers, I think we'll be looking at a combination of architectures.  We've got a white paper coming out on this topic shortly (one already issued by our parent for the cable TV sector).

NWR weather radio is not going away - the FCC made it clear that the legacy EAS will cooexist with the next-gen system for the "foreseeable future".  NWS will start to push their CAP weather alerts into the IPAWS aggregator sometime in the 4Q2011-1Q2012 timeframe.

I'd expect that some states will rely primarily on state CAP systems, and these would interface with IPAWS to get to mobile alerts at a minimum (see Richards post on "PLAN" - also known as CMAS).  EAS-CAP units will interact with these state systems, as well as polling IPAWS.  In almost of third of the country, states are already using a "push" system over Internet and satellite.

Some states my choose to rely on the IPAWS server, and have EAS-CAP units poll the aggregator solely.  They'll still need to acquire CAP authoring tools (IPAWS conformed), though.

Edward Czarnecki, Ph.D.
Senior Director - Strategy, Development and Regulatory Affairs
Monroe Electronics, Inc. / Digital Alert Systems
ed.czarnecki at monroe-electronics.com

www.monroe-electronics.com
www.digitalalertsystems.com

-----Original Message-----
From: Alex Hartman [mailto:goober at goobe.net]

Up here in MN, 1 minute is all it takes sometimes for a tornado todrop out of the sky, but predicting the weather up here (or anywherefor that matter) is impossible. But 1m would i think be a goodinterval, 30s would be a LOT of traffic on the server loads. 5m is fartoo long, a lot can happen in 5 minutes.But i have a question about this "federal aggregator" thing... firsti've heard of such a thing. Why is it even needed? For a tornadowarning, i'd sure as heck hope the alert is coming from my local NWSoffice for activation, not the feds! If anything, it should bereversed, the state servers should poll the fed server for messages,not the other way around. If the whole CAP system is dependent upon afederal "centralized" server, whomever designed the system should beshot.--Alex HartmanKVSC RadioOn Tue, May 10, 2011 at 11:47 PM, Richard_Rudman  wrote:> I have a question for Al:>> How much time will it take for a CAP message from a state input to get to the federal aggregator server and prepare it for "polling"?>> As far an answer to one of Al's questions:>> If we are talking about tornado or other highly time-critical warnings, I would submit that a five minute polling interval is too long. It would be interesting to see how people feel about this after the recent spate of serious tornadoes. For tornado-prone areas, maybe CAP-EAS boxes in those areas should poll every minute -- or more?>> Richard Rudman_______________________________________________This is the EAS Forum Discussion ListPlease invite your friends to join our Forum!http://lists.radiolists.net/mailman/listinfo/easAnd, remember the main page: http://eas.radiolists.net