This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Hi Marck, re: which datastreams do you want to REQUEST from upstream IDD nodes? > The most important one is Forecast Model Output, followed by textual weather > bulletins > and satellite data. Mainly for the Caribbean area. OK. The volumes of the various datastreams that could be involved vary from very modest (global textual observations, IDD IDS|DDPLUS datastream), to intermediate (satellite imagery; IDD datastreams UNIWISC and NIMAGE) to potentially very high (moderate, IDD HRS datasteam; intermediate to high IDD NGRID datastream; very high IDD CONDUIT datastream). To get an idea of the volumes of data in the various datastreams that compose the IDD flow, please review the following snapshot from one of the cluster nodes that comprises the toplevel IDD relay that we operate in UCAR: Data Volume Summary for uni16.unidata.ucar.edu Maximum hourly volume 24822.986 M bytes/hour Average hourly volume 15602.857 M bytes/hour Average products per hour 318834 prods/hour Feed Average Maximum Products (M byte/hour) (M byte/hour) number/hour NEXRAD2 5692.283 [ 36.482%] 7967.348 64686.698 CONDUIT 3298.325 [ 21.139%] 6063.057 71513.628 NEXRAD3 1967.077 [ 12.607%] 2587.342 89026.023 FSL2 1506.577 [ 9.656%] 1717.147 1673.047 FNMOC 1182.267 [ 7.577%] 6358.167 3800.674 NGRID 1145.089 [ 7.339%] 2132.688 20600.116 HDS 335.027 [ 2.147%] 609.231 17521.488 NIMAGE 173.934 [ 1.115%] 329.983 205.814 FNEXRAD 87.234 [ 0.559%] 107.327 70.674 GEM 86.949 [ 0.557%] 371.783 1000.326 IDS|DDPLUS 51.098 [ 0.327%] 64.253 47988.744 EXP 45.649 [ 0.293%] 91.147 370.860 UNIWISC 21.039 [ 0.135%] 31.514 21.116 LIGHTNING 6.924 [ 0.044%] 11.767 349.209 DIFAX 3.320 [ 0.021%] 12.619 4.814 GPS 0.066 [ 0.000%] 0.071 0.977 re: what is your network bandwidth > Our speed is 10 mbps OK, but how much of that is already in full, continuous use? I can safely say that this pipe will _not_ allow you to receive much of the very high volume CONDUIT datastream. re: > We are familiar with linux (centos/fedora/opensuse. Very good. We have been a RedHat shop pretty much for our entire involvement with Linux. We run Fedora releases on most machines, but have begun to deploy more CentOS machines to better match what is increasingly a "standard" configuration in the Unidata community. re: > Regarding the forward and reverse DNS, I can inform you that the way the unix > box is > setup dns is configured to use our isp dns. As is the case with NOAA's ssl > vpn our > static ip is 206.48.100.225. OK. There is no reverse DNS (IP -> name) for the static IP you list: % nslookup 206.48.100.225 Server: 192.168.72.2 Address: 192.168.72.2#53 ** server can't find 225.100.48.206.in-addr.arpa.: NXDOMAIN What is the IP address of the machine you would run the LDM on (my impression is it would be different from 206.48.100.225)? re: > We do receive also WIFS (former wafs) and GIFS (former wmo gts) from NOAA. > But these have limited model data. OK. re: > We got interested in IDD when installing Gempak from your site. We are > running wrf and > using gempak to display the data. Very good. We are willing to help find an upstream site to feed you the data you want (and are able to receive given your current bandwidth). Before contacting Unidata sites to see who would be willing to help, we need to do as much investigating on bandwidth, DNS issues, etc. as possible (to alleviate extra work by the site). One thing that makes extra work for an upstream is having to modify their LDM configuration to ALLOW feed REQUESTs by machine(s) that do not have forward and reverse DNS. The two ways of adding the needed ALLOW (by hardwiring a name for an IP in one's /etc/host file, or by adding an ALLOW by IP address) are both brittle, so sites are reluctant to accept the likely ongoing configuration responsibilities involved. Another question: - are you assigned static IPs by your ISP? You mentioned that you have a static IP for the machine you are using for NOAA's SSL VPN, but I do not know if the machine that has this IP is the one that you would like to use to receive IDD traffic. Cheers, Tom -- **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: VRK-635010 Department: Support IDD Priority: Normal Status: Closed