MACCS Comms Review – 15 December 2004 Page 1 SRI International MACCS Communications Network Status Review Roy Stehle SRI International Center for GeoSpace Studies Menlo Park, CA December 2004

MACCS Comms Review – 15 December 2004 Page 2 SRI International Agenda o Design Overview o Sample Data Set o View Hardware o Discussion Items

MACCS Comms Review – 15 December 2004 Page 3 SRI International MACCS Remote Site Hardware o Computer – 850 MHz Celeron, 256-MB RAM, 80-GB hard drive, Floppy, CD-RW, Linux o NAL Research A3LA-I Iridium Transceiver o Trimble ACE-III GPS Module o NAROD Magnetometer Interface

MACCS Comms Review – 15 December 2004 Page 4 SRI International Network Architecture o Remote MACCS sites share a DoD Iridium channel o Data Transport Net Server at SRI manages the link and newsgroup data distribution; generates HTTP status pages and distribution o Newsgroup data replicated to alternate sites (e.g., Augsburg College, Boston University) Internet Local News Server MACCS-1 MACCS-2 SRI’s News Server

MACCS Comms Review – 15 December 2004 Page 5 SRI International Iridium Link Timeshare o Iridium link acquisition: 0.25 to 1.7 sec o Data transfer: 20 to 80 sec –bzip2 compression of data o Nominal data latency: < 5 sec o Link back-off strategy for difficult channels o Host at SRI sets channel transmission strategy MACCS-1 MACCS min Link Handshake Data Transfer

MACCS Comms Review – 15 December 2004 Page 6 SRI International Data Transfers as Usenet Message Attachments o Well developed protocols for reliable message transfer over a wide variety of networks o Headers provide the metadata; content can be any type of data

MACCS Comms Review – 15 December 2004 Page 7 SRI International Newsgroup Message Queue o Remote device writes data files to shared network folder o Posting program reacts to network characteristics o Newsgroup acts as a queue to hold messages –Multiple newsgroups can be handled

MACCS Comms Review – 15 December 2004 Page 8 SRI International Newsgroup Publication and Subscription o Single producer, many consumers o Short-term history with automatic expiration o Archive possible at master or at image sites o Data interpretation for quick-look display o Status monitor with distribution of Alerts through distribution

MACCS Comms Review – 15 December 2004 Page 9 SRI International Multisite Data Processing o SRI server can aggregate data from multiple sites (e.g., MACCS-1, MACCS-2)

MACCS Comms Review – 15 December 2004 Page 10 SRI International Distribution to Remote News Servers o Periodic replication of data to one or more remote servers (e.g., Augsburg College, Boston University) o Local file access, with access controls, avoids Internet delays o Data replication and archival o Bidirectional

MACCS Comms Review – 15 December 2004 Page 11 SRI International Directory of Data Files o File name format: YYYYMMDD-HHMMSS.[hi|lo]res.dat # ll data/ total 184K drwxr-xr-x 2 transport transport 4.0K Dec 6 17:25./ drwxr-xr-x 7 transport transport 4.0K Dec 6 17:06../ -rw-rw-r-- 1 transport transport 26K Dec 6 16: hires.dat -rw-rw-r-- 1 transport transport 2.6K Dec 6 16: lores.dat -rw-rw-r-- 1 transport transport 26K Dec 6 16: hires.dat -rw-rw-r-- 1 transport transport 2.6K Dec 6 16: lores.dat -rw-rw-r-- 1 transport transport 26K Dec 6 16: hires.dat -rw-rw-r-- 1 transport transport 2.6K Dec 6 16: lores.dat -rw-rw-r-- 1 transport transport 26K Dec 6 16: hires.dat -rw-rw-r-- 1 transport transport 2.6K Dec 6 16: lores.dat -rw-rw-r-- 1 transport transport 26K Dec 6 16: hires.dat -rw-rw-r-- 1 transport transport 2.6K Dec 6 17: lores.dat -rw-rw-r-- 1 transport transport 10K Dec 6 17: hires.dat -rw-rw-r-- 1 transport transport 1012 Dec 6 17: lores.dat

MACCS Comms Review – 15 December 2004 Page 12 SRI International High-resolution Data Sample o GPS Timestamp –Every 0.5 sec o Data samples (3-axis) # tail -f data/ hires.dat :27: :27: :27: :27: :27: :27: :27: :27: :27: :27: :27: :27: :27: :27:

MACCS Comms Review – 15 December 2004 Page 13 SRI International Low-resolution Data Sample # tail -f data/ lores.dat :10: :10: :10: :10: :10: :10: :10: :10: :10: :10: :10: :10: :11: :11: :11: :11: :11: :11: :11: :11: :11: :11: :11: :11: :12: :12: :12: :12: :12: :12: :12: :12: :12: :12: :12: :12: :13: :13: :13: :13: :13: :13: :13: :13: :13: :13: :13: :13: :14: :14: :14: :14: :14: :14: :14: :14: :14: :14: :14: :14:

MACCS Comms Review – 15 December 2004 Page 14 SRI International Iridium and Ethernet Network Routing Tables # sudo /sbin/ifup iridium # netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface UH ppp U eth U eth UG ppp0 # sudo /sbin/ifdown iridium # netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface U eth U eth UG eth0 # ping fireball.sri.com PING fireball.sri.com ( ) 56(84) bytes of data. 64 bytes from fireball.SRI.COM ( ): icmp_seq=0 ttl=63 time=0.811 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=1 ttl=63 time=0.745 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=2 ttl=63 time=0.757 ms

MACCS Comms Review – 15 December 2004 Page 15 SRI International Iridium Network Timing # tail -f link.log [ :56:34 INFO] LinkControl: Posted link stats [ :56:34 INFO] LinkControl: Shutting down the link... [ :56:51 INFO] LinkControl: Link is down (took 00:00:17.27 to hangup) [ :00:10 INFO] LinkControl: Bringing up the Iridium link... [ :00:50 INFO] LinkControl: Link is up (took 00:00:39.86 to dial) [ :00:50 INFO] LinkControl: Posting... [ :01:15 INFO] LinkControl: Transferred 3480 bytes in 24 secs ( bytes/sec [ :01:15 INFO] LinkControl: Posted link stats [ :01:15 INFO] LinkControl: Shutting down the link... [ :01:22 INFO] LinkControl: Link is down (took 00:00:07.22 to hangup) [ :05:10 INFO] LinkControl: Bringing up the Iridium link... [ :06:34 INFO] LinkControl: Link is up (took 00:01:24.31 to dial) [ :06:34 INFO] LinkControl: Posting... [ :07:14 INFO] LinkControl: Transferred 3480 bytes in 40 secs (86.86 bytes/sec [ :07:14 INFO] LinkControl: Posted link stats [ :07:14 INFO] LinkControl: Shutting down the link... [ :07:22 INFO] LinkControl: Link is down (took 00:00:07.23 to hangup)

MACCS Comms Review – 15 December 2004 Page 16 SRI International Iridium Network Ping Statistics # ping fireball.sri.com PING fireball.sri.com ( ) 56(84) bytes of data. 64 bytes from fireball.SRI.COM ( ): icmp_seq=0 ttl=63 time=5135 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=1 ttl=63 time=4230 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=2 ttl=63 time=3395 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=3 ttl=63 time=2581 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=4 ttl=63 time=2404 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=5 ttl=63 time=2289 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=6 ttl=63 time=2350 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=7 ttl=63 time=2333 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=8 ttl=63 time=2415 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=9 ttl=63 time=2402 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=10 ttl=63 time=2303 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=11 ttl=63 time=2291 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=12 ttl=63 time=2375 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=13 ttl=63 time=2359 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=14 ttl=63 time=2443 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=15 ttl=63 time=2337 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=16 ttl=63 time=2333 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=17 ttl=63 time=2407 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=18 ttl=63 time=4800 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=19 ttl=63 time=3897 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=20 ttl=63 time=2987 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=21 ttl=63 time=2339 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=22 ttl=63 time=2325 ms 64 bytes from fireball.SRI.COM ( ): icmp_seq=23 ttl=63 time=2412 ms --- fireball.sri.com ping statistics packets transmitted, 24 received, 7% packet loss, time 32951ms rtt min/avg/max/mdev = / / / ms, pipe 7

MACCS Comms Review – 15 December 2004 Page 17 SRI International Items for Discussion o Schedule –Student visit –Shipment to Boston University –Field deployment o SRI as Prime News Host –Network monitoring – alerts o Data archival –Researcher responsibility –Local news aging o Difficult link management strategy –Latency requirements –Need for low resolution data o CD burning at remote sites –Is it needed if data verified after receipt over Iridium?