1. Routing across wired and wireless mesh networks Experimental compound internetworking with OSPF Juan Antonio CorderoMatthias PhilippEmmanuel Baccelli INRIA Saclay – Île-de-France (France) 8 th International Wireless Communications and Mobile Computing Conference Limassol (Cyprus), August 27-31, 2012

2. / 132 Agenda Motivation: compound internetworks in the Internet core Introduction to OSPF Our contribution: objectives and experiments The testbed Data plane results Control plane results

3. / 133 Compound internetworks in the Internet Set of interconnected wireless and wired networks in a single domain Autonomous System Rest of the Internet

4. / 134 Compound internetworks in the Internet Set of interconnected wireless and wired networks in a single domain Compound Autonomous System Rest of the Internet

5. / 135 OSPF basic operation What is OSPF ? Open Shortest Path First Link-state routing protocol Main Interior Gateway Protocol (IGP) used in Internet routing How does it work ? Interface types (Supported networks) Point-to-point Broadcast MANET-like Packet types Neighbor sensing : Hellos Topology flooding : LS-Updates, LS-Acks Database sychronization : LS-Reqs, DB Description

6. / 136 Contribution : Objectives and Experiments Experimental evaluation in a compound internetworking testbed (layer 3 perspective) Confirm/dismiss underlying assumptions on previous research On the data plane : UDP flows and pings On the control plane : OSPF control traffic structure Extension of OSPF for operation in compound internetworks

7. / 137 Wired/wireless static internetwork, 6 computers MAC layer : 802.3 Ethernet (wired) 802.11b WLAN (wireless) Routing : OSPF for IPv6 point-to-point interface (wired) MPR-OSPF MANET interface (wireless) 3 with wired interfaces (DECchip 21140) 3 with wireless interfaces (Broadcom BCM4306 WLAN) 2 with wired and wless interfaces (hybrids) Testbed description

8. / 138 Study of control traffic eth0 S h2h2 w2w2 eth1 eth0 wlan0 h2h2 w2w2 eth0 eth1 eth0 wlan0 h1h1 eth0 eth1 eth0 wlan0 h1h1 w3w3 1 wired hop + 1 wireless hop 1 + 21 + 3 S h1h1 w1w1 w3w3 S h2h2 w2w2 w1w1 w3w3 Logical topologies : three scenarios Scenario I Scenario IIScenario III Data flow (UDP/ICMP)

9. / 139 Computers position at the Computer Science Lab of École Polytechnique (LIX, France) Sh1h1 h2h2 w2w2 w1w1 w3w3 w3w3 PC with wired ifs. PC with (only) wless ifs. Physical topology 10 m

10. / 1310 Quality of communication degrades (almost) linearly as packets traverse more wireless hops Packet Delivery Ratio (/1) Data plane results Round Trip Time (msec) UDP data flowsICMP requests (pings) m ~ -15%

11. / 1311 Control plane results : wireless/wired comparison hybrid1:eth1hybrid1:wlan0 Periodic pattern in both cases Different role of flooding in wireless and wired components

12. / 1312 Control plane results : OSPF control traffic in wireless wless3:wlan0 Synchronization traffic is present during the whole lifetime of a wireless (static) link

13. / 1313 To conclude Routing with OSPF in compound (wired/wireless) internetworks OSPF optimization for wireless mesh operation Link-state synchronization traffic to be minimized Flooding bursts to be avoided General observations Number of wireless links in compound routes should be minimized Optimal compound routes are not necessarily those with less hops Metrics for wireless networks Integrated shortest-path routing for compound internetworks

14. / 1314 Questions ? E-mail : j.a.cordero@gmail.comj.a.cordero@gmail.com

15. / 1315 Backup slides

16. / 1316 Compound Autonomous Systems Compound Autonomous System Rest of the Internet

17. / 1317 Testbed configuration details CBR UDP traffic Sender bit rate: 100 pkt/sec Packet payload: 1024 B CBR real effective traffic rate ~ 300 kbps Flow duration: 5 min/flow 60 iterations/value ICMP traffic 84 iterations/value OSPF parameters (common for wired/wireless interfaces, for fairness) HelloInterval: 2 sec DeadInterval: 10 sec RxmtInterval: 5 sec AckInterval: 2 sec MinLSInterval: 5 sec MinLSArrival: 1 sec LSRefreshInterval: 60 sec Other parameters IEEE 802.11b: 11 Mbps (nominal data rate), no RTS/CTS, ARQ IP MTU: 1500 B

18. / 1318 Sh1h1 h2h2 w2w2 w1w1 w3w3 w3w3 PC with wired ifs. PC with (only) wless ifs. Physical topology : routes for data flows 10 m 2 hops = 1 + 1 3 h. = 1 + 2 4 h. = 1 + 3

19. / 1319 Link-state routing Link-State Advertisements (LSAs) Link-state Database (LSDB) Shortest Path Tree (SPT) Routing Table ( Dijkstra ) ( next-hop )