1. FTP Server Structure
Markus Heene, DWD

2. Agenda Structure of FTP Server for Dissemination Phase
Basic estimates of directories
24h Cache requirement

3. Dissemination Phase – Tree 1
Level 1: CCCC
Level 2: Alpha / Binary
Alpha: T1T2 – Data Type
GRIB: A2 – Reference Time
GRIB: ii – Level
GRID: A1 – Geographical Area,
A2 – Reference Time
CREX: T1T2A1
YY: Day of the month
GG: Hour of observation

4. Basic estimates of directories
Level 1 – CCCC ~ 300 according to
Level 1 – CCCC ~ 1500 according to VolC1 published 17 September 2013
Level 1 – CCCC on FTP Server: 286
Idea: If CCCC ~ 1500, we can create an additional top level directory ISO 2-letter or ISO 3-letter country code to group the CCCCs
Level 2 – alpha or binary
Level 3 – GRIB – A2: 26 Reference times where 4 currently not assigned
Level 3 – T1T2 in case of Alpha: ~ 174
Level 3 – BUFR T1T2A1: ~ 57
Level 3 – GRID: only 4 CCCC’s provide GRID data
Level 3 – CREX: only 8 CCCC’s provide GRID data
Level 3 – PIC: ~ 25 CCCC’s provide PIC data

5. Basic estimates of directories – Archive directory
Archive: This directory contains 2-minute archives of all data received in this time interval
Max archive size (zip): ~ 60.4 MB
Max archive size (gz): ~ 58.2 MB
Max archive size (bzip2): ~ 55.7 MB
Max archive size (xz): ~ 51.8 MB
One day (17th Oct. 2013: 5.4 GB [zip])
Suggestion: /RUMS_AMDCN: Directory with 2-minute archives of all data from GISC Moscow’s AMDCN
Max archive size (xz): ~ 34 KB
One day (17th Oct. 2013: 927 KB [xz])
Compressed archives reduce transfer data volume and we get an additional checksum for free