ALERT2 ALERT2 Source Addressing Source Addressing Message System Message System (SAMS) (SAMS)

David Leader, James LoganDavid Leader, James Logan

ALERT2 Protocol Technical Working Group ALERT2 Protocol Technical Working Group National Hydrologic Warning CouncilNational Hydrologic Warning Council

May 2, 2013May 2, 2013

What is it?What is it?

Source Address is the numeric address of Source Address is the numeric address of an ALERT2 transmitting sitean ALERT2 transmitting site

Range of possible source addresses is 0-Range of possible source addresses is 0-65K; much greater than the number of 65K; much greater than the number of ALERT Site IDs (1-8K, same as ALERT ALERT Site IDs (1-8K, same as ALERT Sensor IDs)Sensor IDs)

Will be reused throughout country and Will be reused throughout country and worldworld

ALERT2 is everywhereALERT2 is everywhere

ALERT and ALERT2 data are already ALERT and ALERT2 data are already being transmitted via being transmitted via Radio (including repeaters of multi agency Radio (including repeaters of multi agency

sub-nets)sub-nets) Internet extends the reach of radioInternet extends the reach of radio Data exchange between base stationsData exchange between base stations

Identifiers need to be managed, otherwise Identifiers need to be managed, otherwise confusion will create problemsconfusion will create problems

Source addresses: Use existing ALERT site ID Source addresses: Use existing ALERT site ID or new higher addressor new higher address

Some software examplesSome software examples

Database Database station ID station ID 1603 does 1603 does not changenot change

Source Source address address 10033 10033 defined as defined as remote tagremote tag

Source Address Reuse Concern Source Address Reuse Concern

How do we prevent one receiving site from How do we prevent one receiving site from receiving ALERT2 data from two sites with receiving ALERT2 data from two sites with the same source address?the same source address?

Frequency separation may not be enough Frequency separation may not be enough to determine remote site when repeaters to determine remote site when repeaters concentrate data from multiple sub-netsconcentrate data from multiple sub-nets

Best practice is to prevent source address Best practice is to prevent source address reuse in regional areareuse in regional area

Proposed SolutionProposed Solution

Create a database of source addressesCreate a database of source addresses Connect to database through the InternetConnect to database through the Internet Let database be self managedLet database be self managed Allow free access to databaseAllow free access to database Ask for donations to fund database hosting Ask for donations to fund database hosting

and design web page user accessand design web page user access

Source Address Management SystemSource Address Management System

Create a database of ALERT2 site source Create a database of ALERT2 site source address, location, and owning agencyaddress, location, and owning agency

Web based access to databaseWeb based access to database Database is simple and self administeredDatabase is simple and self administered Provide tools to check if an ALERT2 Provide tools to check if an ALERT2

source address is in use in regionsource address is in use in region

SAMS Home PageSAMS Home Page

SAMS DatabaseSAMS Database

Owner tableOwner table Agency identificationAgency identification Login/passwordLogin/password Regional lat/long boundariesRegional lat/long boundaries

Site tableSite table Source addressSource address Lat/long coordinatesLat/long coordinates Owner agency identifierOwner agency identifier Site informationSite information

Agency PageAgency Page

Site PageSite Page

Source Address RequestSource Address Request

Source address and owner agency ID Source address and owner agency ID together uniquely define an ALERT2 site.together uniquely define an ALERT2 site.

SAMS suggests an available source SAMS suggests an available source address for a new site request by the address for a new site request by the owner agency.owner agency.

Agency can also request a specific source Agency can also request a specific source address (could be existing ALERT site ID). address (could be existing ALERT site ID). SAMS will give feedback if source address SAMS will give feedback if source address

doesn’t pass muster.doesn’t pass muster.

Source Address ValidationSource Address Validation

Example SAMS ValidationExample SAMS Validation

Block Address Block Address Source address not reused within a given Source address not reused within a given

distance (1000 miles)distance (1000 miles) Common AddressCommon Address

Sites with same source address are listed so Sites with same source address are listed so that you are aware of conflictsthat you are aware of conflicts

ProximityProximity Notify if location is within 3 miles of any other Notify if location is within 3 miles of any other

existing source address locations existing source address locations

SAMS Prototype SpecificsSAMS Prototype Specifics

Source address validation is Source address validation is recommended but not requiredrecommended but not required Source address reuse allowed by owner if Source address reuse allowed by owner if

necessarynecessary Batch spreadsheet entry will be supportedBatch spreadsheet entry will be supported Site radio frequency, TDMA slot, and site Site radio frequency, TDMA slot, and site

metadata not stored in databasemetadata not stored in database Concern is that metadata may not be kept up Concern is that metadata may not be kept up

to date by ownerto date by owner

SAMS AvailableSAMS Available

Up for review by ALERT2 Technical Up for review by ALERT2 Technical Working Group (TWG) now.Working Group (TWG) now.

Open for registering sites now at Open for registering sites now at http://alert2.org

Fully functional after ALERT2 TWG after ALERT2 TWG meeting at NHWC conference in Florida meeting at NHWC conference in Florida June 2, 2013.June 2, 2013.

Download presentation from:Download presentation from:http://hydrolynx.com/presentations/ALERT2-SAMS.ppt