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<ul><li><p>Ad Hoc and Wireless MeshNetworking</p><p>Laura Marie Feeneylmfeeney@sics.se</p><p>Datakommunikation III, HT 2006</p><p>Overview</p><p>Ad hoc and wireless mesh networksI Ad hoc network (MANet)</p><p>I operates independently of networkinfrastructure</p><p>I nodes cooperate to provide networkservices</p><p>I Mesh networkI supplements network infrastructureI nodes cooperate to provide Internet</p><p>access</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without base station</p><p>infrastructure</p></li><li><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without base station</p><p>infrastructure</p><p>I nodes cooperate to provide connectivity</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without base station</p><p>infrastructure</p><p>I nodes cooperate to provide connectivity</p><p>I every node is a router (no default</p><p>router)</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without base station</p><p>infrastructure</p><p>I nodes cooperate to provide connectivity</p><p>I every node is a router (no default</p><p>router)</p><p>ad hoc routing problem</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p></li><li><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without centralized</p><p>administration</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without centralized</p><p>administration</p><p>I nodes cooperate to provide services</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without centralized</p><p>administration</p><p>I nodes cooperate to provide services</p><p>I address allocation (no DHCP)</p><p>Ad hoc network</p><p>mobile wireless network</p><p>capable of autonomous operation</p><p>I operates without centralized</p><p>administration</p><p>I nodes cooperate to provide services</p><p>I address allocation (no DHCP)</p><p>I fairness and security</p></li><li><p>Example</p><p>network nodes (mobiles, laptops, PDAs)</p><p>Example</p><p>wireless communication</p><p>Example</p><p>equivalent topology</p><p>Example</p><p>discover multihop route</p></li><li><p>Example</p><p>route failure due to mobility</p><p>Example</p><p>dynamic route repair</p><p>Example</p><p>extend infrastructure</p><p>Example</p><p>How is a MANET different from other</p><p>networks?</p><p>I Internet</p><p>I WLAN/Cellular</p><p>I MobileIP</p></li><li><p>Internet</p><p>default router</p><p>Internet routing(+ humans)</p><p>networkprovider</p><p>simple default router at edges</p><p>expertise managing core</p><p>WLAN/celluar</p><p>nodes communicate only with base-station</p><p>Mobile IP</p><p>correspondent</p><p>CN</p><p>MNhome</p><p>FA</p><p>MobileIP allows a node to change its point of</p><p>attachment to the network</p><p>Mobile IP</p><p>CNFA</p><p>HA</p><p>MN</p><p>home agent (HA) tunnels traffic to the node</p></li><li><p>Applications</p><p>I Military/rescue</p><p>(no infrastructure)</p><p>Applications</p><p>I Military/rescue</p><p>(no infrastructure)</p><p>I Disaster management</p><p>(damaged infrastructure)</p><p>Applications</p><p>I Military/rescue</p><p>(no infrastructure)</p><p>I Disaster management</p><p>(damaged infrastructure)</p><p>I Spontaneous networks</p><p>(meeting/conference room)</p><p>Applications</p><p>I Military/rescue</p><p>(no infrastructure)</p><p>I Disaster management</p><p>(damaged infrastructure)</p><p>I Spontaneous networks</p><p>(meeting/conference room)</p><p>I Personal area networks</p></li><li><p>Applications</p><p>I Military/rescue</p><p>(no infrastructure)</p><p>I Disaster management</p><p>(damaged infrastructure)</p><p>I Spontaneous networks</p><p>(meeting/conference room)</p><p>I Personal area networks</p><p>I Campus area networks</p><p>Applications</p><p>I Extend coverage</p><p>improve range or capacity in a building</p><p>Applications</p><p>I Extend coverage</p><p>improve range or capacity in a building</p><p>I Community mesh networks</p><p>share network connectivity with</p><p>neighbors</p><p>Applications</p><p>I Extend coverage</p><p>improve range or capacity in a building</p><p>I Community mesh networks</p><p>share network connectivity with</p><p>neighbors</p><p>I Developing countries</p><p>provide cheap communication</p><p>infrastructure</p></li><li><p>History</p><p>Not a new idea</p><p>I US DARPA (1970s)</p><p>History</p><p>Not a new idea</p><p>I US DARPA (1970s)</p><p>I Amateur (ham) radio operators (1970s)</p><p>packet radio</p><p>History</p><p>Not a new idea</p><p>I US DARPA (1970s)</p><p>I Amateur (ham) radio operators (1970s)</p><p>packet radio</p><p>I renewed interest mid-1990s</p><p>History</p><p>Not a new idea</p><p>I US DARPA (1970s)</p><p>I Amateur (ham) radio operators (1970s)</p><p>packet radio</p><p>I renewed interest mid-1990s</p><p>I IETF MANET working group (1997)</p></li><li><p>History</p><p>Not a new idea</p><p>I US DARPA (1970s)</p><p>I Amateur (ham) radio operators (1970s)</p><p>packet radio</p><p>I renewed interest mid-1990s</p><p>I IETF MANET working group (1997)</p><p>I startup companies (2000)</p><p>Ad hoc routing</p><p>Outline</p><p>I challenges</p><p>I design choices</p><p>I protocol example</p><p>I wireless communication</p><p>Challenges</p><p>I distributed state in unreliable</p><p>environment</p><p>Challenges</p><p>I distributed state in unreliable</p><p>environment</p><p>I changing topology</p><p>I limited communication capacity</p><p>I limited battery capacity</p></li><li><p>Challenges</p><p>I distributed state in unreliable</p><p>environment</p><p>I changing topology</p><p>I limited communication capacity</p><p>I limited battery capacityI wireless communication</p><p>I variable link qualityI non-symetric linksI interference and collisions</p><p>CriteriaI effectiveness</p><p>I convergence/recoveryI scalability (number of nodes, density)</p><p>CriteriaI effectiveness</p><p>I convergence/recoveryI scalability (number of nodes, density)</p><p>I performanceI data throughputI route latency (delay)I route optimality</p><p>(hops/stability/diversity)I overhead cost</p><p>(packets/bandwidth/energy)</p><p>Alphabet Soup</p><p>many proposed protocols:</p><p>AODV CEDAR ABR FSR</p><p>TORA GSR OLSR LANMAR</p><p>ZRP LAR DSR OSPF++</p><p>RDMAR CBRP DSDV WRP</p><p>TBRPF CGSR GPSR HSR</p></li><li><p>Design choices</p><p>protocols divided into a few main categories</p><p>I on-demand (reactive)</p><p>I table driven (proactive)</p><p>I hierarchical/cluster-based</p><p>I geographic/position-based</p><p>Reactive Routing</p><p>find routes as needed (on demand)</p><p>I advantagesI no overhead maintaining unused routes</p><p>I disadvantagesI high route latencyI optimization?</p><p>Proactive routing</p><p>table-based, more similar to conventional</p><p>routing</p><p>I advantagesI low route latencyI state information</p><p>I disadvantagesI high overhead (periodic table updates)I route accuracy depends on updates</p><p>AODV (DYMO)</p><p>Ad hoc On demand Distance Vector</p><p>Perkins et.al.</p></li><li><p>AODV (DYMO)</p><p>Ad hoc On demand Distance Vector</p><p>Perkins et.al.</p><p>conventional distance vector</p><p>I nodes exchange distance information (to</p><p>all nodes) with their neighbors</p><p>I periodic exchange and immediate</p><p>update for changes</p><p>I routing table selects shortest path</p><p>AODV (DYMO)</p><p>Ad hoc On demand Distance Vector</p><p>Perkins et.al.</p><p>conventional distance vector</p><p>I nodes exchange distance information (to</p><p>all nodes) with their neighborsI periodic exchange and immediate</p><p>update for changesI routing table selects shortest path</p><p>exchange a lot of information that is never</p><p>used</p><p>AODV (DYMO)</p><p>on-demand variant of conventional distance</p><p>vector</p><p>AODV (DYMO)</p><p>on-demand variant of conventional distance</p><p>vector</p><p>I route request (RREQ) packet is flooded</p><p>through the network</p></li><li><p>AODV (DYMO)</p><p>on-demand variant of conventional distance</p><p>vector</p><p>I route request (RREQ) packet is flooded</p><p>through the network</p><p>I route discovery creates (temporary)</p><p>reverse paths back to the source</p><p>AODV (DYMO)</p><p>on-demand variant of conventional distance</p><p>vector</p><p>I route request (RREQ) packet is flooded</p><p>through the network</p><p>I route discovery creates (temporary)</p><p>reverse paths back to the source</p><p>I route reply (RREP) turns a valid reverse</p><p>path into a route</p><p>AODV (DYMO)</p><p>handling topology change</p><p>AODV (DYMO)</p><p>handling topology change</p><p>I link failure causes route error (RERR)</p><p>I destination managed sequence number</p><p>ensures loop freedom</p></li><li><p>AODV (DYMO)</p><p>handling topology change</p><p>I link failure causes route error (RERR)</p><p>I destination managed sequence number</p><p>ensures loop freedom</p><p>AODV is RFC 3562 (experimental)</p><p>DYMO is IETF Internet draft</p><p>AODV (simplified)</p><p>7</p><p>1</p><p>2</p><p>6</p><p>11</p><p>13103</p><p>5</p><p>12</p><p>4</p><p>8</p><p>914</p><p>route from node 1 to node 14</p><p>AODV (RREQ)</p><p>1479</p><p>8</p><p>4</p><p>12</p><p>5</p><p>3 10 13</p><p>11</p><p>6</p><p>1</p><p>2</p><p>14?1 hop</p><p>broadcast flooding of route request</p><p>wireless multicast advantage</p><p>AODV (RREQ)</p><p>5</p><p>1hop</p><p>41&gt;14: via 1</p><p>8</p><p>1hop</p><p>914</p><p>1&gt;14: via 1</p><p>3</p><p>6</p><p>7</p><p>111hop</p><p>13</p><p>1</p><p>101&gt;14: via 1</p><p>212</p><p>node from which RREQ was received defines</p><p>reverse path to source</p></li><li><p>AODV (RREQ)</p><p>14?</p><p>2 hops</p><p>2</p><p>6</p><p>1</p><p>14</p><p>11</p><p>13103</p><p>5</p><p>12</p><p>4</p><p>8</p><p>97</p><p>2 hops</p><p>2 hops</p><p>14?</p><p>14?</p><p>RREQ is flooded though the network</p><p>AODV (RREQ)</p><p>2hop</p><p>6</p><p>14</p><p>1</p><p>1310</p><p>2</p><p>3</p><p>5</p><p>12</p><p>4</p><p>8</p><p>97</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 1)</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1 hop</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 5)2hop</p><p>2hop</p><p>2hop</p><p>1&gt;14: via 2</p><p>11</p><p>reverse paths are recorded</p><p>AODV (RREQ)</p><p>14?</p><p>3 hops</p><p>3 hops 14</p><p>3</p><p>7</p><p>1</p><p>6</p><p>3 hops</p><p>1310</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>3 hops</p><p>11</p><p>2 14?</p><p>14?</p><p>14?</p><p>unreliable broadcast</p><p>destination managed sequence number, ID</p><p>prevent looping</p><p>AODV (RREQ)</p><p>3hop</p><p>79</p><p>8</p><p>4</p><p>12</p><p>5</p><p>3 10 13</p><p>1</p><p>14</p><p>6</p><p>11</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 1)</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1 hop</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 5)2hop</p><p>2hop</p><p>2hop</p><p>1&gt;14: via 22hop</p><p>1&gt;14: via 83hop</p><p>1&gt;14: via 83hop</p><p>1&gt;14: via 7</p><p>2</p><p>reverse paths are recorded</p></li><li><p>AODV (RREQ)</p><p>4 hops</p><p>4 hops2</p><p>14</p><p>3</p><p>7</p><p>1</p><p>6</p><p>11</p><p>1310</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>4 hops14?</p><p>14?</p><p>14?</p><p>broadcast collision problem (jitter)</p><p>AODV (RREQ)</p><p>4hop</p><p>6</p><p>14</p><p>1</p><p>2</p><p>13103</p><p>5</p><p>12</p><p>4</p><p>8</p><p>97</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 1)</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1 hop</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 5)2hop</p><p>2hop</p><p>2hop</p><p>1&gt;14: via 22hop</p><p>1&gt;14: via 8</p><p>1&gt;14: via 83hop</p><p>1&gt;14: via 73hop</p><p>3hop</p><p>1&gt;14 via 10</p><p>1&gt;14 via 104hop</p><p>11</p><p>reverse paths are recorded</p><p>AODV (RREQ)</p><p>14?</p><p>3</p><p>7 14</p><p>13</p><p>1</p><p>6</p><p>11</p><p>10</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9 5 hops</p><p>5 hops14?</p><p>2</p><p>broadcast flooding is very expensive</p><p>AODV (RREQ)</p><p>5 hops</p><p>79</p><p>8</p><p>4</p><p>12</p><p>5</p><p>3 10 13</p><p>1</p><p>14</p><p>6</p><p>11</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 1)</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1 hop</p><p>1&gt;14 (via 1)</p><p>1 hop</p><p>1&gt;14: via 3</p><p>1&gt;14 (via 5)2hop</p><p>2hop</p><p>2hop</p><p>1&gt;14: via 22hop</p><p>1&gt;14: via 8</p><p>1&gt;14: via 83hop</p><p>1&gt;14: via 73hop</p><p>3hop</p><p>1&gt;14 via 10</p><p>1&gt;14 via 104hop</p><p>4hop</p><p>14!2</p><p>RREQ arrives at the destination</p><p>two routes are discovered</p></li><li><p>AODV (RREP)</p><p>14</p><p>7</p><p>3</p><p>14</p><p>1</p><p>6</p><p>11</p><p>10</p><p>2</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>13</p><p>destination sends unicast RREP (sets</p><p>sequence number)</p><p>activate reverse path</p><p>AODV (RREP)</p><p>14</p><p>27</p><p>3</p><p>14</p><p>1</p><p>6</p><p>11</p><p>10</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>13</p><p>destination sends unicast RREP (sets</p><p>sequence number - not shown)</p><p>AODV (RREP)</p><p>11</p><p>6</p><p>1</p><p>9</p><p>3</p><p>7</p><p>1314</p><p>14</p><p>14 via 13</p><p>214</p><p>8</p><p>4</p><p>12</p><p>5</p><p>10</p><p>RREP messages activates reverse path</p><p>AODV (RREP)</p><p>2</p><p>5</p><p>12</p><p>14</p><p>4</p><p>148</p><p>14</p><p>79</p><p>13</p><p>14</p><p>via 13</p><p>1</p><p>3</p><p>6</p><p>1114</p><p>10</p><p>via 10</p><p>RREP messages activates reverse path</p></li><li><p>AODV (RREP)</p><p>via 8</p><p>9</p><p>8</p><p>4</p><p>12</p><p>5</p><p>10</p><p>11</p><p>6</p><p>1</p><p>14</p><p>3</p><p>7</p><p>1314</p><p>14</p><p>14 via 13</p><p>via 101414</p><p>2</p><p>RREP reaches source route discovery</p><p>complete</p><p>AODV (RREP)</p><p>via 5</p><p>9</p><p>8</p><p>4</p><p>12</p><p>5</p><p>10</p><p>11</p><p>6</p><p>1</p><p>14</p><p>3</p><p>7</p><p>1314</p><p>14</p><p>14 via 13</p><p>14 via 10via 814</p><p>2</p><p>source adopts destination sequence number</p><p>AODV</p><p>via 10</p><p>9</p><p>8</p><p>4</p><p>12</p><p>5</p><p>10</p><p>11</p><p>6</p><p>1</p><p>14</p><p>3</p><p>7</p><p>1314</p><p>14 via 5 via 814</p><p>14 via 13</p><p>14</p><p>2</p><p>traffic flows along forward route</p><p>reverse path information times out</p><p>AODV(RERR)</p><p>via 10</p><p>9</p><p>8</p><p>4</p><p>12</p><p>5</p><p>10</p><p>11</p><p>6</p><p>1</p><p>14</p><p>3</p><p>7</p><p>1314</p><p>14 via 5 via 814</p><p>14 via 13</p><p>14</p><p>2</p><p>link failure</p><p>how to be sure?</p></li><li><p>AODV(RERR)</p><p>10</p><p>14</p><p>5</p><p>12</p><p>via 5</p><p>4 14</p><p>8</p><p>via 13</p><p>9</p><p>3</p><p>14</p><p>7</p><p>via 8</p><p>13</p><p>1</p><p>6</p><p>14</p><p>11</p><p>2</p><p>14</p><p>node generates route error message (RERR)</p><p>AODV(RERR)</p><p>via 13</p><p>9</p><p>8</p><p>4</p><p>12</p><p>5</p><p>10</p><p>11</p><p>6</p><p>1</p><p>14</p><p>3</p><p>7</p><p>1314</p><p>14 via 5</p><p>14</p><p>2</p><p>forwarded to source</p><p>AODV(RERR)</p><p>4</p><p>12</p><p>5</p><p>10</p><p>11</p><p>6</p><p>1</p><p>14</p><p>8</p><p>7</p><p>1314 via 13</p><p>14 via 1014?</p><p>2</p><p>14</p><p>9</p><p>3</p><p>initiate new route discovery (RREQ)</p><p>AODV(RERR)</p><p>97</p><p>3</p><p>14</p><p>1</p><p>6</p><p>11</p><p>10</p><p>2</p><p>5</p><p>12</p><p>4</p><p>8</p><p>13</p><p>discover new route (latency)</p></li><li><p>AODV(RERR)</p><p>14?</p><p>7</p><p>3</p><p>14</p><p>1</p><p>6</p><p>2</p><p>11</p><p>10</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>14</p><p>14 via 5 via 814</p><p>14</p><p>14 via 10</p><p>via 1313</p><p>what about a local repair?</p><p>initiate RREQ from point of failure</p><p>AODV(RERR)</p><p>14?</p><p>7</p><p>3</p><p>14</p><p>1</p><p>6</p><p>2</p><p>11</p><p>10</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>14</p><p>14 via 5 via 814</p><p>14</p><p>14 via 10</p><p>via 1313</p><p>what about a local repair?</p><p>initiate RREQ from point of failure</p><p>AODV(RERR)</p><p>via 10</p><p>7</p><p>3</p><p>14</p><p>1</p><p>6</p><p>2</p><p>11</p><p>10</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>14</p><p>14 via 5 via 814</p><p>14</p><p>14 via 10</p><p>via 13</p><p>14</p><p>13</p><p>lower latency</p><p>AODV(RERR)</p><p>via 10</p><p>7</p><p>3</p><p>14</p><p>1</p><p>6</p><p>2</p><p>11</p><p>10</p><p>5</p><p>12</p><p>4</p><p>8</p><p>9</p><p>14</p><p>14 via 5 via 814</p><p>14</p><p>14 via 10</p><p>via 13</p><p>14</p><p>13</p><p>lower latency but longer routes</p></li><li><p>AODV(DYMO)</p><p>I (over)-simplified description here</p><p>I further complexities and optimizations</p><p>I AODV-UU implementation is</p><p>well-known</p><p>CriteriaI effectiveness</p><p>I convergence/recoveryI scalability (number of nodes, density)</p><p>I performanceI data throughputI route latency (delay)I route optimality</p><p>(hops/stability/diversity)I overhead cost</p><p>(packets/bandwidth/energy)</p><p>OLSR</p><p>Optimized Link State Routing</p><p>Clausen et.al</p><p>OLSR</p><p>Optimized Link State Routing</p><p>Clausen et.al</p><p>conventional link-state routing</p><p>I beacon to determine neighbors</p><p>I for each node, disseminate its links to</p><p>all other nodes</p><p>I use SPF algorithm to generate routing</p><p>table</p></li><li><p>OLSR</p><p>Optimized Link State Routing</p><p>Clausen et.al</p><p>conventional link-state routing</p><p>I beacon to determine neighborsI for each node, disseminate its links to</p><p>all other nodesI use SPF algorithm to generate routing</p><p>table</p><p>high overhead, exchange information for links</p><p>that are never used</p><p>OLSR</p><p>variant of conventional link state routing</p><p>OLSR</p><p>variant of conventional link state routing</p><p>I for each node, disseminate only some of</p><p>its links</p><p>I for each node, only disseminate</p><p>information received via some links</p><p>I use SPF to generate routing table</p><p>OLSR</p><p>variant of conventional link state routing</p><p>I for each node, disseminate only some of</p><p>its links</p><p>I for each node, only disseminate</p><p>information received via some links</p><p>I use SPF to generate routing table</p><p>some links = multipoint selector set</p></li><li><p>OLSR</p><p>IETF RFC 3626 (experimental)</p><p>2-hop Neighborhood</p><p>broadcast periodic hello messages</p><p>I each message contains a list of</p><p>neighbors</p><p>I each node discovers its 2-hop</p><p>neighborhood</p><p>I discovers failed links</p><p>I discovers bi-directional links</p><p>Bi-directional Links</p><p>HELLO(3)={1,2,4,7}</p><p>HELLO(6)={2,3,7}</p><p>6</p><p>4</p><p>3</p><p>14</p><p>1</p><p>2</p><p>13</p><p>129</p><p>10</p><p>11</p><p>7</p><p>85</p><p>Bi-directional Links</p><p>NBR(3)={1,2,4,7}</p><p>NBR(3)={1,2,4,7}HELLO(6)={2,3,7}</p><p>5</p><p>3</p><p>14</p><p>1</p><p>2</p><p>13</p><p>129</p><p>10</p><p>11</p><p>7</p><p>8</p><p>6</p><p>4</p></li><li><p>Multipoint Relay</p><p>multipoint relay set (MPR): subset of a</p><p>nodes 1-hop neighbors, such that each of its</p><p>2-hop neighbors is a 1-hop neighbor of a</p><p>node in the MPR set</p><p>Multipoint Relay</p><p>multipoint relay set (MPR): subset of a</p><p>nodes 1-hop neighbors, such that each of its</p><p>2-hop neighbors is a 1-hop neighbor of a</p><p>node in the MPR set</p><p>minimum set of 1-hop neighbors that results</p><p>in the same set of 2-hop neighbors</p><p>Multipoint Relay</p><p>multipoint relay set (MPR): subset of a</p><p>nodes 1-hop neighbors, such that each of its</p><p>2-hop neighbors is a 1-hop neighbor of a</p><p>node in the MPR set</p><p>minimum set of 1-hop neighbors that results</p><p>in the same set of 2-hop neighbors</p><p>each node has an MPR set (not a network</p><p>MPR set)</p><p>Multipoint Relay(MPR set)</p><p>12</p><p>1</p><p>2</p><p>6</p><p>9</p><p>10</p><p>1185</p><p>3</p><p>7</p><p>4</p><p>14</p><p>13</p><p>1-hop and 2-hop neighbors of node 4 ode 5</p><p>is not neede

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