MACCS Comms Review – 15 December 2004 Page 1 SRI International MACCS Communications Network MACCS Communications Network Status Review Status Review Roy Stehle SRI International Center for GeoSpace Studies Menlo Park, CA 94025 [email protected]650-859-2552 15 December 2004
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MACCS Comms Review – 15 December 2004 Page 1 SRI International MACCS Communications Network Status Review Roy Stehle SRI International Center for GeoSpace.
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MACCS Comms Review – 15 December 2004Page 1 SRI International
MACCS Communications Network MACCS Communications Network Status ReviewStatus Review
MACCS Comms Review – 15 December 2004Page 2 SRI International
AgendaAgenda
Design Overview
Sample Data Set
View Hardware
Discussion Items
MACCS Comms Review – 15 December 2004Page 3 SRI International
MACCS Remote Site HardwareMACCS Remote Site Hardware
Computer – 850 MHz Celeron, 256-MB RAM, 80-GB hard drive, Floppy, CD-RW, Linux
NAL Research A3LA-I Iridium Transceiver
Trimble ACE-III GPS Module
NAROD Magnetometer Interface
MACCS Comms Review – 15 December 2004Page 4 SRI International
Network ArchitectureNetwork Architecture
Remote MACCS sites share a DoD Iridium channel
Data Transport Net Server at SRI manages the link and newsgroup data distribution; generates HTTP status pages and e-mail distribution
Newsgroup data replicated to alternate sites (e.g., Augsburg College, Boston University)
Internet
Local News Server
MACCS-1
MACCS-2SRI’s News Server
MACCS Comms Review – 15 December 2004Page 5 SRI International
Iridium Link TimeshareIridium Link Timeshare
Iridium link acquisition: 0.25 to 1.7 sec
Data transfer: 20 to 80 sec– bzip2 compression of data
Nominal data latency: < 5 sec
Link back-off strategy for difficult channels
Host at SRI sets channel transmission strategy
MACCS-1
MACCS-20 8642 10 min
Link Handshake
Data Transfer
MACCS Comms Review – 15 December 2004Page 6 SRI International
Data Transfers as Usenet Message AttachmentsData Transfers as Usenet Message Attachments
Well developed protocols for reliable message transfer over a wide variety of networks
Headers provide the metadata; content can be any type of data
MACCS Comms Review – 15 December 2004Page 7 SRI International
Newsgroup Message QueueNewsgroup Message Queue
Remote device writes data files to shared network folder
Posting program reacts to network characteristics
Newsgroup acts as a queue to hold messages– Multiple newsgroups can be handled
MACCS Comms Review – 15 December 2004Page 8 SRI International
Newsgroup Publication and SubscriptionNewsgroup Publication and Subscription
Single producer, many consumers
Short-term history with automatic expiration
Archive possible at master or at image sites
Data interpretation for quick-look display
Status monitor with distribution of Alerts through e-mail distribution
MACCS Comms Review – 15 December 2004Page 9 SRI International
Multisite Data ProcessingMultisite Data Processing
SRI server can aggregate data from multiple sites(e.g., MACCS-1, MACCS-2)
MACCS Comms Review – 15 December 2004Page 10 SRI International
Distribution to Remote News ServersDistribution to Remote News Servers
Periodic replication of data to one or more remote servers(e.g., Augsburg College, Boston University)
Local file access, with access controls, avoids Internet delays
Data replication and archival
Bidirectional
MACCS Comms Review – 15 December 2004Page 11 SRI International
Directory of Data FilesDirectory of Data Files
File name format: YYYYMMDD-HHMMSS.[hi|lo]res.dat
# ll data/total 184Kdrwxr-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 16:39 20041206-163500.hires.dat-rw-rw-r-- 1 transport transport 2.6K Dec 6 16:40 20041206-163500.lores.dat-rw-rw-r-- 1 transport transport 26K Dec 6 16:44 20041206-164000.hires.dat-rw-rw-r-- 1 transport transport 2.6K Dec 6 16:45 20041206-164000.lores.dat-rw-rw-r-- 1 transport transport 26K Dec 6 16:49 20041206-164500.hires.dat-rw-rw-r-- 1 transport transport 2.6K Dec 6 16:50 20041206-164500.lores.dat-rw-rw-r-- 1 transport transport 26K Dec 6 16:54 20041206-165000.hires.dat-rw-rw-r-- 1 transport transport 2.6K Dec 6 16:55 20041206-165000.lores.dat-rw-rw-r-- 1 transport transport 26K Dec 6 16:59 20041206-165500.hires.dat-rw-rw-r-- 1 transport transport 2.6K Dec 6 17:00 20041206-165500.lores.dat-rw-rw-r-- 1 transport transport 10K Dec 6 17:26 20041206-172500.hires.dat-rw-rw-r-- 1 transport transport 1012 Dec 6 17:26 20041206-172500.lores.dat
MACCS Comms Review – 15 December 2004Page 12 SRI International
High-resolution Data SampleHigh-resolution Data Sample
# sudo /sbin/ifdown iridium# netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth00.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
# ping fireball.sri.comPING fireball.sri.com (128.18.26.41) 56(84) bytes of data.64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=0 ttl=63 time=0.811 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=1 ttl=63 time=0.745 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=2 ttl=63 time=0.757 ms
MACCS Comms Review – 15 December 2004Page 15 SRI International
Iridium Network TimingIridium Network Timing
# tail -f link.log[2004-12-15 09:56:34 INFO] LinkControl: Posted link stats[2004-12-15 09:56:34 INFO] LinkControl: Shutting down the link ...[2004-12-15 09:56:51 INFO] LinkControl: Link is down (took 00:00:17.27 to hangup)[2004-12-15 10:00:10 INFO] LinkControl: Bringing up the Iridium link ...[2004-12-15 10:00:50 INFO] LinkControl: Link is up (took 00:00:39.86 to dial)[2004-12-15 10:00:50 INFO] LinkControl: Posting...[2004-12-15 10:01:15 INFO] LinkControl: Transferred 3480 bytes in 24 secs (143.37 bytes/sec[2004-12-15 10:01:15 INFO] LinkControl: Posted link stats[2004-12-15 10:01:15 INFO] LinkControl: Shutting down the link ...[2004-12-15 10:01:22 INFO] LinkControl: Link is down (took 00:00:07.22 to hangup)[2004-12-15 10:05:10 INFO] LinkControl: Bringing up the Iridium link ...[2004-12-15 10:06:34 INFO] LinkControl: Link is up (took 00:01:24.31 to dial)[2004-12-15 10:06:34 INFO] LinkControl: Posting...[2004-12-15 10:07:14 INFO] LinkControl: Transferred 3480 bytes in 40 secs (86.86 bytes/sec[2004-12-15 10:07:14 INFO] LinkControl: Posted link stats[2004-12-15 10:07:14 INFO] LinkControl: Shutting down the link ...[2004-12-15 10:07:22 INFO] LinkControl: Link is down (took 00:00:07.23 to hangup)
MACCS Comms Review – 15 December 2004Page 16 SRI International
Iridium Network Ping StatisticsIridium Network Ping Statistics# ping fireball.sri.comPING fireball.sri.com (128.18.26.41) 56(84) bytes of data.64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=0 ttl=63 time=5135 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=1 ttl=63 time=4230 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=2 ttl=63 time=3395 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=3 ttl=63 time=2581 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=4 ttl=63 time=2404 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=5 ttl=63 time=2289 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=6 ttl=63 time=2350 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=7 ttl=63 time=2333 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=8 ttl=63 time=2415 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=9 ttl=63 time=2402 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=10 ttl=63 time=2303 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=11 ttl=63 time=2291 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=12 ttl=63 time=2375 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=13 ttl=63 time=2359 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=14 ttl=63 time=2443 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=15 ttl=63 time=2337 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=16 ttl=63 time=2333 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=17 ttl=63 time=2407 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=18 ttl=63 time=4800 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=19 ttl=63 time=3897 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=20 ttl=63 time=2987 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=21 ttl=63 time=2339 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=22 ttl=63 time=2325 ms64 bytes from fireball.SRI.COM (128.18.26.41): icmp_seq=23 ttl=63 time=2412 ms --- fireball.sri.com ping statistics ---26 packets transmitted, 24 received, 7% packet loss, time 32951msrtt min/avg/max/mdev = 2289.599/2798.130/5135.301/828.190 ms, pipe 7
MACCS Comms Review – 15 December 2004Page 17 SRI International
Items for DiscussionItems for Discussion
Schedule– Student visit– Shipment to Boston University– Field deployment
SRI as Prime News Host– Network monitoring– E-mail alerts
Data archival– Researcher responsibility– Local news aging
Difficult link management strategy– Latency requirements– Need for low resolution data
CD burning at remote sites– Is it needed if data verified after receipt over Iridium?