Configuration Information for receiving data from the
RADAR PRODUCT CENTRAL COLLECTION / DISSEMINATION SERVICE
(RPCCDS):

Communications

1. A directly connected router to the NWS using (at a minimum) a T1 (1.5 Megabits/sec) speed communications link.
   • NOTE: Contact for installation of a connection is: Paul Noonan, Phone: 301-713-0864 ext 154
     Email: paul.noonan@noaa.gov
   
   
2. The properly configured network using four IP addresses per connection. The IP address will be assigned upon router-to-router configuration of the established T1 connection. The configuration requires the use of uncoordinated IP addresses which will be issued by the NWS to each directly connected multicast subscriber. Host routes to the NWS dispatcher server systems NIDServA and NIDServB registered IP addresses must be configured in the partner's router to permit multicast data flow.
   • NOTE: Contact for network configuration is: Jackie Lord, Phone: 301-713-0877 ext 126
     Email: jacqueline.lord@noaa.gov
   
   
3. A computing platform capable of receiving 35 Gigabytes of WSR-88D product data files per day. The computer platforms which will support the NWS provided receiver software is listed below.

Client-side Software

1. The NWS requires the use of the StarBurst™ receiver software which is available for downloading from the NWS. It will either be "OmniCast™ Advanced Receiver" Ver. 1.7.5 for Operating Systems WindowsNT/2K, AIX, or Sun Solaris; or by using the MFTP basic client receiver software specifically selected at download based upon the "Receiving Operating System Platform" of choice from the list below.
   • NOTE: The receiver software (platform specific and selected at download) is available from the NWS through the Telecommunication Operations Center [password required] by contacting:
     
     Phone: Allan Darling at 301-713-0882 ext 114; e-mail: allan.darling@noaa.gov
   
   
2. The software documentation is contained in the downloaded "tar" file as an "Adobe Acrobat Reader v3.0" format (.pdf) in a doc directory associated with each product and/or supported platform.
   
   NOTE: OmniCast™ software is a product by StarBurst Software® and was presently selected by the NWS for intial distribution of radar data using the multicast procedure; however, this does not constitute any endorsement by the National Weather Service for StarBurst Software or their "StarBurst OmniCast" software product.

Receiving Platforms

Assumptions

Multicast customers have:

1. An active TCP/IP connection to NWS with at least T1 (1.5 Megabits/sec) available bandwidth
   • NOTE: Multicast Packets are not currently supported on the Internet.
   
   
2. An equivalent router comparable to a CISCO 2501 running SF25C-11.2.21P IOS 2500 Series IP
   • NOTE: This is the only connectivity tested.
   
   
3. A compatible receiver computing platform capable of receiving 35 Gigabytes of WSR-88D NEXRAD product data files per day

   Compatible receiver computing platforms:

   1. RS6000/AIX R4.2 and later
   2. HP9000/HP-UX R10.20 and later
   3. SGI/Irix
   4. SunSPARC/Solaris R2.6 and later
   5. Compaq Alpha/Tru64 Unix
   6. PentiumPC/RedHat Linux R6.0 and later
   7. PentiumPC/Unixware 2.0 and later
   8. PentiumPC/Windows9x or NT R4.0 and later (XP not supported)
      
      
      • NOTE: Even though the complete list above is provided, the ability of some of these operating systems to receive and also process this large volume of data within the same system may be in doubt. It is recommended to only receive this data stream, if some of the client target systems are used, and process it elsewhere.
      
      
4. The implemented IP addresses on the router and receiving computer interfaces.

WSR-88D Data Stream

All available NEXRAD product data is delivered in Lempel-Ziv compressed 'tar' archive files named as tar88dHHMM#.Z containing the actual product data files with relative path structure. Archive contents are uniquely identified using directory path components formatted as "DC.radar/DS.ptype/SI.cccc/sn.####" (see: WSR-88D Product Files )

where:

• HHMM# is the archive file creation timestamp and sequence number
• DC.radar is the relative lead directory path component for the radar product data file,
• DS.ptype is the NEXRAD product type identifier (see: WSR-88D Product Files )
• SI.cccc is the four character alphabetic site identifier code designation (see: WSR-88D Product Files )
• sn.#### is a four digit product file sequence number for each filename of the product stored.

The WSR-88D NEXRAD product data is delivered in 10 second intervals upon receipt at the dispatcher server using the Omnicast open group model. NEXRAD clients should choose a computing platform with the operating characteristics consistent with their particular data processing requirements. No attempt will be made to resend a product archive file to non-responsive or otherwise inoperative receiver systems. Therefore, NEXRAD product data files missed will need to be individually pulled from the NWS ftp server farm ( ftp://ptgftp.nws.noaa.gov/ ) to obtain any missing product data. The description of the product identifiers and the radar site location list are contained in the  Central Weather Surveillance Radar Server  product files for FTP. It is the responsibility of the RPCCDS subscriber to detect when and if this should be necessary.

MULTICAST CONFIGURATION GUIDE

Network Configuration Procedures

This multicast implementation uses a combination of both coordinated (registered) and uncoordinated (private) IP address space for both point-to-point and multicast group addressing to accomplish combined unicast and multicast operation. This will facilitate the dedicated use of the T1 connection for just multicast operation. Any recovery FTP activity can not be permitted on this connection as the full set of radar products will fill the T1.

To facilitate the timely delivery of NEXRAD product data, the NWS has elected to deliver files using six separate channels corresponding to UDP port numbers 5402, through 5407 inclusive. The Omnicast default multicast group delivered "out of the box" for announcing delivery of files is 224.0.1.88. As this group number is already reserved for "B1RMonitor" applications (see: Internet Multicast Addresses ) and to avoid possible conflicts with other multicast transport applications including StarBurst MFTP, the NWS has chosen to announce files using 224.20.29.11 for open group NEXRAD product delivery. Actual data transfer is performed using yet another group number specified at the time the receiver registers with the dispatcher to receive any particular file. To improve the security and effectiveness of NEXRAD product delivery, the source addresses of the two multicast dispatcher servers should be coded into the receiver configuration using the RXSERVER= receive jobfile configuration option. This address can be determined by looking up hosts nidserva.awips.noaa.gov and nidservb.awips.noaa.gov using DNS lookup.

Software Configuration Procedures

STEPS

1. Obtain the Omnicast receiver software for your receiver platform and Operating System
   • NOTE:  The "OmniCast Sender" software is Version 1.7.5 and is running on the NWS RISC 6000 (AIX) radar multicast server called "NIDServA" and NIDServB (backup).
   
   
   
2. Perform the StarBurst installation procedure
   
   • NOTE:   The receiver application does not require administrative privileges to install or run on either Windows or Unix systems. However, to prevent filling up the disk partition with log file data, access to the crontab utility in Unix or the task scheduler service in Windows is recommended or log file rotation and other file system maintenance procedures may be performed by invoking appropriate scripts set to run in the background. The recommended install subdirectory is '/opt/sburst' for Unix and 'C:\sburst' for Windows.
   
   
   
3. Add the six reserved port numbers as indicated above in the appropriate place to the '/etc/services' file if Unix receiver
   
   • NOTE:   This will require administrative privileges on the receiver system (access to the "root" account).
     Example entry:           'mftp      5402/udp         #Omnicast multicast receiver port'
     
     
     
4. Obtain the file processing scripts, associated software and documentation along with the six sample Omnicast receiver job files if using Omnicast for your receiver platform and Operating System from NWS/TOC
   
   • NOTE: These files should be accessible via ftp by contacting the person shown above for the password. The software is located at: Software and Documentation Available from the NWS. Omnicast job files (ending in .jrx) should be saved in a 'jobs' subdirectory created in the 'omnicast' subdirectory. If running the 'sbclient_cli' basic receiver utility under Unix, the six client configuration files (ending in .cfg) should be created by replicating  sbclient.cfg to the sbclient1.cfg, etc. files saved in the 'client' subdirectory and configuring the "PORTNUM=" receiver port numbers as indicated above. Unix scripts should be placed in '/usr/local/bin' or other appropriate subdirectory included in the "PATH" environment variable. Windows batch files and other executable utilities should be placed in a 'bin' subdirectory in the partition allocated to receive the extracted NEXRAD product data files.
     
     For the convenience of the user, the use of  tar to extract the data is provided using the t option which only lists the contents of the archive rather than actually extracting the data. Once the receiver system is prepared to process all the incoming data, the file processing script (either  'tarproc' in Unix or 'tarto.bat' in Windows) should be halted and the file edited to change the t to an x so that the product data files are saved to the indicated location. The received file processing utilities produce their own log files and these will need periodic rotation and/or archiving to avoid filling up the file system with log data. It is the responsibility of the user to determine the most effective method to do this or modify the scripts not to produce the log data in the first place.
   
   
   
5. Tailor the job files to reflect local path configuration
   
   • NOTE: It is wise to create a separate disk partition and file-system for the location of the product data and log files to avoid filling up the file-system where the Operating System and Application software are installed. If these are moved from their default locations, the corresponding options in the jrx/cfg files should be modified to reflect their new locations relative to the file-system root. The ListenIP option in all .cfg files for the client receivers or the  RXPUBLIC1 option in the .jrx files for Omnicast receivers should be set to the multicast group address indicated in the "Network Configuration Procedures" section above if the default group is not globally modified from the default setting using the Omnicast administrator utility (see step 7 below). Some Unix client receiver software will only permit UDP port configuration through the  sbclient.cfg files rather than through a command line option; configure as appropriate.
     
     If the receiver system is a multi-homed host, it will also be necessary to set the  XMITADDR and  RECVADDR options if using the client receivers, or the  TXIPADDR and  RXIPADDR .jrx options if using Omnicast, to the IP address assigned to the interface which will be used to receive the multicast traffic. If using Omnicast, the hostname and IP address must be configured in the application database for the interface used to transmit and receive data to/from the multicast dispatcher ("sender") server (see step 7 below and the Omnicast documentation).
   
   
   
6. Perform Omnicast startup procedure if using Omnicast
   • NOTE: This may be done automatically as a part of the installation procedure (an icon is provided for this purpose in Start/Programs/StarBurst/Omnicast). It is also advisable that the system administrator configure the system startup procedures to automatically start Omnicast running with appropriate user privileges at boot time should the system need to be restarted for any reason (see also step 8 below).
   
   
   
7. If using Omnicast, configure the log file creation frequency to daily and modify the default public address from '224.0.1.88' to that indicated in the "Network Configuration Procedures" section above with the admin console "dispatcher" selection and restart Omnicast. This may also be accomplished by submitting an appropriate job file to the reciever using the Command-Line-Interface (CLI) utility as described in the documentation.
   
   
   
8. Start the receiver file processing script obtained above
   
   • NOTE: This script is critical to prevent the received compressed tar archive files from rapidly filling up the disk partition where the sbdata subdirectory is located. It periodically checks for files located in this subdirectory, decompresses and extracts their contents and then remove them. It is the client's responsibility to process the extracted WSR-88D NEXRAD product data files according to your local application and move/remove them as required to prevent overflow of the disk partition where they are stored. If the multicast receiver software is configured to start automatically at boot time (see step 6 above or step 9 below), this procedure should also be configured to be started along with it to avoid file system overflow.
   
   
   Example invocation:
   - On Unix:
   1. nohup tarproc 5 /opt/sburst/omnicast/sbdata /aux >> /tmp/tarproc.log&
   
   
   - On Windows:
   1. Start a "Command Prompt" window
   2. tarproc 5 C:\sburst\omnicast\sbdata F:\aux
   3. Minimize the "Command Prompt" window
      Do not logout  (doing so will halt all running programs)
   
   
   
   • NOTE: The pause time between checks for new files in the  sbdata subdirectory (the first argument to the program) can be set to values greater than 5 to increase its efficiency by processing more received files per pass but values less than 5 do not make much sense as new archive files will appear at a rate no greater than one every 10 seconds from the dispatcher.
     
     
   
   
9. Submit/run the six receiver job files as configured above
   
   • Notes: Either the sbcli or the Omnicast "User Console" GUI can be used for this purpose (consult the StarBurst documentation supplied with their software). If running the  sbclient_cli basic receiver utility on Unix, invoke the script  'sbclients 6' provided to start all six processes necessary to receive data on all six receive channels. It is also advisable that the Unix system administrator configure the system startup procedures to run this script with appropriate privileges at boot time should the system need to be restarted for any reason (see also step 8 above). The  sbclients utility also accepts arguments 'show' and 'kill' to provide a convenient way to list the active client receiver processes or shut them all down if necessary.
   
   
   
10. Configure any log file rotation or other maintenance scripts as necessary
    
    • Notes:The importance of this cannot be overemphasized. The large number of files along with the sheer volume of data being received by a NEXRAD multicast receiver system is likely to cause resource shortages unless the proper rotation of log files and the removal of received data is regularly performed. Once the receiver system runs out of resources, it will no longer register dispatcher announcements and continuous reception of data will be interrupted. The subdirectories that are most likely to fill up with large numbers of files and/or data besides the location of the extracted product data files are:
      a) the sbdata subdirectory,
      b) the sbtemp subdirectory if there are aborted file delivery attempts, and the  logs subdirectory if running Omnicast.
      The sbrotlog and sbtempcln utilities for Unix users are provided as examples of such scripts for the convenience of the user. It is also possible for other subdirectories and/or file systems unrelated to Omnicast containing log file data maintained by the operating system to also cause resource shortages on a receiver system. It is the responsibility of the receiver system administrator to be aware of these system log files and implement appropriate preventative measures to prevent system resource shortages which could cause interruption of the multicast receiver.