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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
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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) • Internet extends the reach of radio • 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 10033 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 Database • Owner table • Agency identification • Login/password • Regional lat/long boundaries • Site table • Source address • Lat/long coordinates • Owner agency identifier • Site information
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.
Example SAMS Validation • Block Address • 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 • Proximity • 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 • 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
SAMS Available • Up for review by ALERT2 Technical Working Group (TWG) now. • Open for registering sites now at http://alert2.org • Fully functional after ALERT2 TWG meeting at NHWC conference in Florida June 2, 2013. • Download presentation from:http://hydrolynx.com/presentations/ALERT2-SAMS.ppt