ALERT2 Source Addressing Message System (SAMS) David Leader, James Logan ALERT2 Protocol Technical Working Group National Hydrologic Warning Council May 2, 2013

What is it?  Source Address is the numeric address of an ALERT2 transmitting site  Range of possible source addresses is 0- 65K; much greater than the number of ALERT Site IDs (1-8K, same as ALERT Sensor IDs)  Will be reused throughout country and world

ALERT2 is everywhere  ALERT and ALERT2 data are already being transmitted via Radio (including repeaters of multi agency sub-nets) Radio (including repeaters of multi agency sub-nets) Internet extends the reach of radio Internet extends the reach of radio Data exchange between base stations Data exchange between base stations  Identifiers need to be managed, otherwise confusion will create problems

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

Some software examples  Database station ID 1603 does not change  Source address defined as remote tag

Source Address Reuse Concern  How do we prevent one receiving site from receiving ALERT2 data from two sites with the same source address?  Frequency separation may not be enough to determine remote site when repeaters concentrate data from multiple sub-nets  Best practice is to prevent source address reuse in regional area

Proposed Solution  Create a database of source addresses  Connect to database through the Internet  Let database be self managed  Allow free access to database  Ask for donations to fund database hosting and design web page user access

Source Address Management System  Create a database of ALERT2 site source address, location, and owning agency  Web based access to database  Database is simple and self administered  Provide tools to check if an ALERT2 source address is in use in region

SAMS Home Page

SAMS Database  Owner table Agency identification Agency identification Login/password Login/password Regional lat/long boundaries Regional lat/long boundaries  Site table Source address Source address Lat/long coordinates Lat/long coordinates Owner agency identifier Owner agency identifier Site information Site information

Agency Page

Site Page

Source Address Request  Source address and owner agency ID together uniquely define an ALERT2 site.  SAMS suggests an available source address for a new site request by the owner agency.  Agency can also request a specific source address (could be existing ALERT site ID). SAMS will give feedback if source address doesn’t pass muster. SAMS will give feedback if source address doesn’t pass muster.

Source Address Validation

Example SAMS Validation  Block Address Source address not reused within a given distance (1000 miles) Source address not reused within a given distance (1000 miles)  Common Address Sites with same source address are listed so that you are aware of conflicts Sites with same source address are listed so that you are aware of conflicts  Proximity Notify if location is within 3 miles of any other existing source address locations Notify if location is within 3 miles of any other existing source address locations

SAMS Prototype Specifics  Source address validation is recommended but not required Source address reuse allowed by owner if necessary Source address reuse allowed by owner if necessary  Batch spreadsheet entry will be supported  Site radio frequency, TDMA slot, and site metadata not stored in database Concern is that metadata may not be kept up to date by owner Concern is that metadata may not be kept up to date by owner

SAMS Available  Up for review by ALERT2 Technical Working Group (TWG) now.  Open for registering sites now at  after ALERT2 TWG meeting at NHWC conference in Florida June 2,  Fully functional after ALERT2 TWG meeting at NHWC conference in Florida June 2,  Download presentation from: