Val Schmidt 22 July 2004 Collaborators Toby Martin - Oregon State Geoff Davis - Scripps

1. SWAPSHIP to SHIP/SHIP to SHORE Wireless Access ProtocolWireless Mesh Networking in the UNOLS Fleet Val Schmidt 22 July 2004 Collaborators Toby Martin - Oregon State Geoff Davis - Scripps El McFadden - USCG Many Thanks to NSF and the LDEO OMA!

2. For two ships operating in close proximity. Sending data between them requires two satellite hops. At ~$35/Megabyte a 1 hour multibeam file (~2000m depth) may cost as much as $700 and take 5-6 hours. Ship to Ship Data Transfer Today Assumes no compression, transfer via MPDS at Ewing’s nominal 500 bps and no intermediate connection.

3. Toby Martin, Oregon State University, R/V Wacoma System Admin 802.11b point to point connection using Lucent”Remote Outdoor Routers” between the R/V Wacoma and R/V Thompson and both ships and the pier. Successful but raised loads of questions. Wireless Working Group and email list begun. Early 802.11 Tests RVTEC - 2002http://pigeon.shipops.orst.edu/swap/rvtec2002/

4. Questions • Was there a need in the UNOLS fleet for such a ship to ship system? • What were the capabilities of currently available commercial hardware? • What impact would this have on the ship’s internal network? • What level of technical skill would be required to maintain such a system? • At what range could we make connections? • What effect would pitch and roll have on connections? • Would we experience interference with other communications systems? • Were there other applications? • Could/should we create a fleet wide system?

5. RVTEC 2003 - Story Scenarios • A ship pulls into its homeport but before the ship moors at the pier, a wireless network link is made automatically to the local shore network and larger Internet. • Same as 1 except the port is not the ship’s home port, but any facility offering this service. • A wireless network link is generated automatically between two ships at sea when in reception range. This requires no user interaction, and automated processes that look for the presence of the other ship will execute over the link to dedicated known hosts on the peer ship.

6. Story Scenarios Continued… • A link is generated automatically between three or more ships at sea when in reception range. If ship A is in range of ship B but not ship C, ship B can still forward packets on to ship C from ship A. (“Hidden nodes” are still routable.) • In the case of 3 or 4, if one ship is outfitted with a broadband satellite link to shore (e.g. HighSeasNet), shipboard personnel can provide the other ships access to that link via the wireless ship-to-ship service.

7. Story Scenarios Continued… • An instrumented buoy outfitted with a wireless radio is externally triggered to attempt a wireless connection with a passing ship. When the connection is made, the buoy’s data and operating status are downloaded to a known server on that ship. • A ship passing within radio range of a participating shore facility maintains a constant data link to shore. The link might serve ships operating near institutions without deep water ports (e.g. an Ice Breaker passing Barrow), or ships conducting local coastal surveys.

8. Practical Requirements • Automatic. • Maintenance free. • Requires little or no increased technical skill on the part of the ship’s staff and no additional personnel. • Relatively secure. • Doesn’t require redesign of ship or shore facility networks.

9. The Search No inexpensive commercial implementations met our requirements. • Ability to make point to point links with multiple participants. • Ability to decentralize routing management.

10. 802.11Wireless Links Infrastructure Basic Service Set (IBSS) AP/Client Model Independent Basic Service Set Ad-hoc Model

11. Wireless Distribution System - Network Bridging Connect network segments instead of hosts Wireless equivalent of a single switch. Layer 2 connection - All bridged segments are in the same IP subnet. Doesn’t scale. Most implementations only support a single link.

12. Open System Interconnection[OSI] Model 7. Application Layer 6. Presentation Layer 5. Session Layer 4. Transport Layer 3. Network Layer Routing packets BETWEEN Networks 2. Data Link Layer Sending packets to hosts WITHIN Networks 1. Physical Layer 802.11 Standard

13. WDS Links with aladin With each WDS link, pseudo network interfaces are created and assigned IP addressing. IP: 10.200.1.33 Net Mask: 255.255.255.252 IP: 10.200.1.34 Net Mask: 255.255.255.252 Connects networks instead of segments. Layer 3 connection. Wireless equivalent of two routers connected by an Ethernet segment.

14. Learning About Network States:Open Shortest Path First OSPF detects link state changes and propagates them between peers to facilitate exchange of routing tables. Net A --> eth0 Net B --> wlan0wds0 Net C --> via 10.200.1.34 Net C --> eth0 Net B --> wlan0wds0 Net C --> via 10.200.1.33 • Network routing tables are updated automatically as links come and go. • Each router independently determines the best route to an endpoint, decentralizing the network. • Intermediate nodes route traffic on to end points that are not locally connected. MESH NETWORKING! Net B Net C Net A

15. The Solution The grass-roots open source wireless community. OSPF http://www.quagga.net Aladin http://www.sown.org.uk/index.php/HomePage HostAP http://www.seattlewireless.net/ Pebble Linux http://www.nycwireless.net

16. SWAP Device Hardware Single Board PC 802.11b PCMCIA Card Compact Flash Card (OS) 15Db Omni-Directional Antenna

17. SWAP Network SWAP HOST SWAP HOST SWAP LOCAL NETWORK SWAP LOCAL NETWORK SWAP DEVICE SWAP DEVICE NAT NAT SHIP’s INTERNAL NETWORK PUBLIC INTERNET

18. SWAP Network Assignments R/V Kilo Moana • Within the Local SWAP Network • 32 Address Space • First address is always the SWAP Host • Last 11 addresses are served up by DHCP • WDS Pool • Smallest 2 host network requires 4 addresses • 32 address pool provides for 8 possible links

19. SWAP Network SHORE SHIP SWAP LOCAL NETWORK SWAP DEVICE NAT SHIP’s INTERNAL NETWORK SHIP

20. An Example

21. Maximum Connection Range Can I “see” the antenna? Do I have enough oomph to shine/see that far?

22. Visual LOS vs. Fresnel Zone P LOS R1 P - LOS<= lambda / 2

23. Fresnel and Earth Clearance Westwern Legend’s Main Mast Height (~24m)

24. Fade Margin • Transmit Power • Pigtail Loss • Cable Loss • Antenna Gain • Free Space Loss • Antenna Gain • Cable Loss • Pigtail Loss • Receiver Sensitivity • 23dB • -.3 dB • -3 dB • 15 dB • ? • 15 dB • -3 dB • -.3 dB • ? Fade margin ?

25. Free Space Loss for Microwave Links • D = distance in meters • f = frequency in MHz

26. Receiver Sensitivity • Seneo/Engenius -- NL/SL2511CD PLUS EXT2 Rate (Mbps) 1 2.5 5 11 Sensitivity (dB) 95 93 91 89 http://www.freenetworks.org/moin/index.cgi/ReceiveSensitivity

27. Fade Margin Plot Minimum Acceptable Margin

28. SWAP Applications Ship’s Web Page Science Party Chat Sessions Shared Directories Incoming Science Party Lines Outgoing “IDT to Deploy America's First Commercial WiFi Phone Service” E-Mail

29. SWAP Applications Distributed GIS of Opportunity

30. Installations WHIO Oregon St. - Corvalis MBARI U of Hawaii - Snug Harbor Scripps

31. Assigned Address Space

32. Closing • Burgeoning new mesh network for cost effective, short range low maintenance links. • Loads of interest in the community. • Loads of application possibilities to make science better, faster, cheaper and easier - or maybe just cooler. • Nearing the “telecom reality check”.