MARCS Overload?

[SLWilson]

If there is a statewide "Emergency" that presses many agencies into service, all trying to utilize MARCS at the same time, what will happen?

Are there enough available frequencies for LOTS of users to communicate at the same time, or, will someone get "bumpped" out of the system when they try to talk? Will agencies have to revert back to their old communications system (if they didn't junk them) to operate during a statewide disaster?

What is the limit on simultaneous users on the network?

Steve/Gallia

 

[seamusg]

If there is a statewide "Emergency" that presses many agencies into service, all trying to utilize MARCS at the same time, what will happen?

Are there enough available frequencies for LOTS of users to communicate at the same time, or, will someone get "bumpped" out of the system when they try to talk? Will agencies have to revert back to their old communications system (if they didn't junk them) to operate during a statewide disaster?

What is the limit on simultaneous users on the network?

Steve/Gallia

If a trunked system gets overloaded it goes to priorities for channel grants. PD and FD are normally first and the trash pickup trucks and [ I hope the politics ] last. On a trunked system every radio and talk group should have a priority, if not it's dead.

 

[medic611]

" IF" a statewide disaster were to happen first and foremost is the local responders ex fire, ems ,law enforcement would deal with the inital disaster. more than likely you would see problems/ failures with their own networks , majority of the state is using repeaters or even simplex systems. Relying on the state to come help usually takes a few hours to a day or two . OSP, EMA are still keeping and using conventional frequencies not every county in ohio is switching to MARCS. Having used a few TRS in my time the priority is safety forces , i'm confident the powers at the state level have reviewed this .

Keep in mind a mass disatser that takes out the power grid , phone lines ect will affect all communications. I have a feeling there are plenty of satellite phones in storage around the state in strategic places to be utilized . Playing the "what if game" if all else fails you use runners to and from the command post .

 

[Yokoshibu]

I have seen it happen in geauga county only a few times (really large fires)... what does it mean... you wait 10 more seconds and by then someone is off the system to free up a channel for you to use... the system will just not crash the only thing that will happen is you will not be able to talk... likely hood of 6-7 nets being used in rural ohio... slim likely hood of 6-7 nets being used in cuyahoga county being used daily is high... if you look at the sites there are more freq's in more urban locations IE cuyahoga county has 4 freq's and portage has 2.

So there will always be the problem of overloading and the result will not be a collapse but rather a gridlock.... The only solution is for the marc's coordinators to be proactive and pre-empt the need for more freq's for more nets in areas with more people. wether or not they are preemptive is yet to be seen. If we were running a TDMA system ie apco25 / 2 you wouldnt have the problems with using 1 freq statewide.

Right now I see some possible problem ares' ie when you have 8-9 agencies using 4 freq's in one county when there is somthing major going on only 4 agencies can talk at a time.... and back we go into the discusion of priority.... who knows where they stand... when you put the FBI, Cleveland PD, DHS, U.S. marshals, Cuyahoga SO, Cleveland fire/ems, all on the same net can you tell me who has priority? imho fire ems first but thats just me.

So hopefully Marcs management see's the problems and is pre-empting the problems but who's to know for sure untill you put anything to work cause everything in life is a theory untill you actually see it work.

Each site is supposed to have backup power

sat phones... yeah about them inmarsat doesnt even have an official answer right now what would happen if every fed. gov't user were to make a call at the same time!

short answer busy signal.

IMHO I would hope each county maintains thier own system with a patch into one of marcs nets ... thats what akron did.

 

[PJH]

Huh?

You can have 90 people on the same talkgroup, but only one can still talk at a time.

A 6 channel site still has plenty of capacity. As mentioned before, public safety users will have the highest priority over other users.

Initial buildouts are based on the survey's of expected user loading. There is no reason to have a 16 channel site when you may only have 15 users on it during peak times. Each Quantar is/was around $15,000 each. That's a lot of money that isn't being utilized. If the time comes where more channels are needed, they will be added. The system has some really cool management software that will generate utilization reports and loading reports.


MARCS's intent is for incident coordination and the like, not for tactical operations that would chew up all the available channels. That's why the radios have simplex/"fireground" channels in them so they won't tie up the system (or anyone elses) and provides a means of communications should the world come to the end and the system fails.

 

[rdale]

"when you put the FBI, Cleveland PD, DHS, U.S. marshals, Cuyahoga SO, Cleveland fire/ems, all on the same net can you tell me who has priority? imho fire ems first but thats just me."

They aren't all on the same net though...

 

[Yokoshibu]

"when you put the FBI, Cleveland PD, DHS, U.S. marshals, Cuyahoga SO, Cleveland fire/ems, all on the same net can you tell me who has priority? imho fire ems first but thats just me."

They aren't all on the same net though...

No they are not all on the same net.... If you only have 4 freq's in cleveland to support them all and they all talk at the same time only 4 will be able to RX/TX into a site at the same time.... the number of nets does not equal the number of RX/TX's at a site.... You can have 1000 nets but if you only have one set of freq's to support 1000 people they are going to have problems.

 

[Yokoshibu]

Initial buildouts are based on the survey's of expected user loading. There is no reason to have a 16 channel site when you may only have 15 users on it during peak times. Each Quantar is/was around $15,000 each. That's a lot of money that isn't being utilized. If the time comes where more channels are needed, they will be added. The system has some really cool management software that will generate utilization reports and loading reports.


MARCS's intent is for incident coordination and the like, not for tactical operations that would chew up all the available channels. That's why the radios have simplex/"fireground" channels in them so they won't tie up the system (or anyone elses) and provides a means of communications should the world come to the end and the system fails.

Hopefully the enginers and directors keep up with the load... but at the cost to a municipality to use the system it makes a load of sense to pay the monthly costs and get on marcs and thus now the system is tactical in nature in certain locations...

hopefully they will limit and cut back who is on it... moving all of the OSP onto it makes sense but day to day operations are hardly strategic.

Hence the akron comment... I hope everyone maintains their own system with a seperate patch into marcs.

 

[PJH]

What are you talking about when you say "nets"?

Talkgroups?

Regional mutual aid talkgroups?

?

Again, if there is legit space crunch, it will taken care of. Its still better than what was there to begin with. Again, unless an entire agency moves over for day to day ops, MARCS is used for coordination, not tactical operations. Those agencies who move day to day operations over will typically have more freq's at the sites to cover the need on the outset.

I think people are reading in to this way too much.

 

[rdale]

No they are not all on the same net.... If you only have 4 freq's in cleveland to support them all and they all talk at the same time only 4 will be able to RX/TX into a site at the same time.... the number of nets does not equal the number of RX/TX's at a site.... You can have 1000 nets but if you only have one set of freq's to support 1000 people they are going to have problems.

What I'm saying is they aren't on the same system... Not sure what "net" refers to if I follow you right. The Cleveland MARCS site doesn't have Cleveland Fire / EMS / Police so that eliminates most of the info in your post right off the bat.

 

[wa8pyr]

when you put the FBI, Cleveland PD, DHS, U.S. marshals, Cuyahoga SO, Cleveland fire/ems, all on the same net can you tell me who has priority? imho fire ems first but thats just me.

All of the agencies you mention will not be on the same net. Each has their own system, and in a major disaster will most likely use their own channels for tactical operations. The pressing need would be for coordination between agencies representing the entire spectrum of the incident command structure. We're talking about strategic communications here as opposed to tactical.

MARCS fits the bill nicely for those "strategic" coordination communications between command posts, which in and of itself will limit the amount of traffic the system would have to handle. Basically, MARCS will allow coordination between Incident Command and the various sub-command posts (fire suppression, rescue, recovery, emergency housing, medical, finance, and so on).

One thing I highly recommend for any serious scannist is to study up on the Incident Command System. This knowledge can help you gain a much greater understanding of radio systems and what their various channels or talkgroups are intended for.

Wikipedia has a very good, basic primer at http://en.wikipedia.org/wiki/Incident_Command_System

Tom WA8PYR

 

[Yokoshibu]

Wow thanks for jumping on my back everyone! I said it and I'll say it again... Marcs should only be strategic in use (ICS C2). but if the state lets every fed agency and local municipality onto the system because it financially makes sense to do so then the system will experience the loading issues... and like I said before I HOPE the state would keep up with it if that "theoretical problem" should happen.

My understanding was the OSHP was supposed to transition to marcs and once again day to day operations is not strategic communication.

Keep in mind one of the first users was the state prison system! so there are many of users and nets (yes talkgroups) that are not strategic for ICS C2 situations by any means.

I said it before and I'll say it again Akron kept thier own system in place and are on a mutual aid talkgroup on marcs (or had planned to tie in several years ago) and I hope every community will do the same.

and I think I'll pass on radio reference's wiki on ICS and attend the classes for ics 1,2,7and 800...

 

[rdale]

"I said it before and I'll say it again Akron kept thier own system in place and are on a mutual aid talkgroup on marcs (or had planned to tie in several years ago) and I hope every community will do the same. "

That's why you'll never see Columbus or Toledo or Cleveland or anyone else on MARS as it is configured today...

 

[PJH]

Gotta stop using net... Its too much military/ham use and has pretty much no bearing in termonlogy in these type of land/mobile radios system/discussions. It throws everyone off.

AGAIN, should a department which to join MARCS full time, more eqiupment will be installed at the effected site(s) to handle the traffic. AGAIN, you can have 5000 users logged into one site on four talkgroups, but people still talk one at a time, so there wouldn't be a loading issue.

The only time there is a loading issue is when there are more ACTIVE talkgroups enabled at a site than there are channels to use. When you are dealing with large scale/multiple agency incidents, those who are respoding will be on specific talkgroups that are preplanned....as in a regional/county mutual aid talkgroup. Again, 5000 users can be on this one talkgroup, but still have to talk one at a time. Your not going to see 100 talkgroups all of the sudden appear and overload the system (though possible, highly unlikely).

FBI, DEA, CIA, KGB and Santa Claus will be on the same talkgroup as everyone else for coordination, then go to their own channels (MARCS, simplex and/or agency specific) for the actual operation.

Remember what MACRS stands for..

 

[red8]

The system should have a failsoft mode, where the agencies have a
pre assigned channel to go to. At that point the system then goes to
a conventional system. Hence the pre assigned channels.