Advanced Security and Mobile Networks

Transcription

1 Advanced Security and Mobile Networks W.Buchanan (1)

2 Research Area Area Define current limitations of technology Refinement Define Define Research Question Faster? More reliable? More configurable? Design Design Analysis Model Model Implement Refinement Refinement Formal Design Phases W.Buchanan (2)

3 Routing Protocols Background Area II Area Main highway Area B Area D Area A Area G Main connection to the Rest of the World (World gateway) Area F Access ontrol W.Buchanan (3)

4 1 AA Net1 Net2 2 Net5 Net4 4 Net6 6 Net8 BB 3 Net3 5 Net BB AA BB BB Alternative Routes BB W.Buchanan (4)

5 Routing based on hops: Route (1,3,5,6) = 4 hops [BEST] Route (1,3,5,2,4,6) = 6 hops Routing based on delay (latency): Route(2,4,6) = = 2.75 Route(2,5,6) = = 2.4 [BEST] Routing based on error probability: P e (2 5)=0.01 P e (5 6)=0.15 P e (2 4)=0.05 P e (4 6)=0.1 P noerror (2,5,6) =(1 0.01) (1 0.15) = P noerror (2,4,6) =(1 0.05) (1 0.1) = [BEST] Best route? W.Buchanan (5)

6 Bandwidth. The data capacity of a link, which is typically defined in bps. Delay. The amount of time that is required to send a packet from the source to a destination. Load. A measure of the amount of activity on a route. Reliability. Relates to the error rate of the link. Hop count. Defined by the number of routers that it takes between the current router and the destination. Ticks. Defines the delay of a link by a number of ticks of a clock. ost. An arbitrary value which defines the cost of a link, such as financial expense, bandwidth, and so on. Best Route Parameters? W.Buchanan (6)

7 Best Route based on hops B H F Network B Network A A ABH ABDFGH ABEH 3 hops 7 hops 4 hops D E Unfortunately hop count may not be the best way to find the best route, as ABH might involve a slow (or unreliable) link, such as BH, where ABEH could be faster (or more reliable). G W.Buchanan (7)

8 Analyse a part of a route that goes from one routing node to another, and reject the worst routes, so that it reduces the complexity of the problem 80 miles Glasgow Falkirk 64 miles Stirling Edinburgh This route would be dismissed Dijkstra s Algorithm W.Buchanan (8)

9 Inverness Oban 120 Stirling 20 Dunfermline Falkirk Glasgow Edinburgh Glasgow to Falkirk Glasgow to Oban Oban to Inverness Oban to Stirling Inverness to Stirling Stirling to Falkirk Stirling to Edinburgh Stirling to Dunfermline Falkirk to Edinburgh Dunfermline to Edinburgh 50 miles 100 miles 90 miles 120 miles 100 miles 5 miles 60 miles 20 miles 70 miles 15 miles Dijkstra s Algorithm W.Buchanan (9)

10 Inverness Oban 120 Stirling 20 Dunfermline Falkirk Glasgow Edinburgh Dijkstra s Algorithm W.Buchanan (10)

11 Inverness Oban 120 Stirling 20 Dunfermline Falkirk Glasgow Edinburgh Dijkstra s Algorithm W.Buchanan (11)

12 Inverness Oban Stirling 20 Dunfermline 5 50 Falkirk Glasgow Edinburgh Edin, Falkirk, Glasgow: Edin, Dunf, Stir, Falk, Glasgow: 120 miles 90 miles W.Buchanan (12)

13 Routing protocols. A routing protocol provides a mechanism for routers to share routing information. These protocols allow routers to pass information between themselves, and update their routing tables. Examples of routing protocols are Routing Information Protocol (RIP), Interior Gateway Routing Protocol (IGRP), Enhanced Interior Gateway Routing Protocol (EIGRP), and Open Shortest Path First (OSPF). Routed protocols. These protocols are any network layer protocol that allows for the addressing of a host and a destination on a network, such as IP and IPX. Routers are responsible for passing a data packet onto the next router in, if possible, an optimal way, based on the destination network address. The definition of an optimal way depends on many things, especially its reachability. With IP, routers on the path between a source and a destination, examine the network part of the IP address to achieve their routing. Only the last router, which is connected to the destination node network, examines the host part of the IP address. Layer 3 protocols W.Buchanan (13)

14 Distance-vector. Distance-vector routing uses a distance-vector algorithm (such as the Bellman-Ford routing algorithm), which uses a direction (vector) and distance to any link in the internetwork to determine the best route. Each router periodically sends information to each of its neighbors on the cost that it takes to get to a distance node. Typically, this cost relates to the hop count (as with RIP). The main problem with distance-vector is that updates to the network are step-bystep, and it has high bandwidth requirements as each router sends its complete routing table to all of its neighbors at regular intervals. Link-state. Link-state involves each router building up the complete topology of the entire internetwork (or at least of the partition on which the router is situated), thus each router contains the same information. With this method, routers only send information to all of the other routers when there is a change in the topology of the network. Linkstate is also known as shortest path first. Typical link-state protocols are OSPF, BGP and EGP. With OSPF, each router builds a hierarchical topology of the internetwork, with itself at the top of the tree. The main problem with link-state is that routers require much more processing power to update the database, and more memory as routers require to build a database with details of all the routers on the network. Routing protocol types W.Buchanan (14)

15 Broadcast. In broadcast, routers transmit their information to other routers at regular intervals. A typical broadcast routing protocol is RIP, in which routers send their complete routing table once every few minutes, to all of their neighbors. This technique tends to be wasteful in bandwidth, as changes in the route do not vary much over short amounts of time. Event-driven. In event-driven routing protocols, routing information is only sent when there is a change in the topology or state of the network. This technique tends to be more efficient than broadcast, as it does not use up as much bandwidth. Type of Update? W.Buchanan (15)

16 Hybrid (IS-IS) Layer Layer 3 protocols Types Types + Link-state + + Distance-vector Routed (IP, IPX, NetBEUI) + + Routing (RIP, OSPF) Session Session Transport Transport Network Network Data Data link link Physical Physical HTTP HTTP TP TP IP IP RIP RIP Ethernet/ Ethernet/ FDDI FDDI Routing Distance metrics Updates Hop count + Delay Tick + Bandwidth + ost + Reliability + Each router Each router transmits routing periodically sends information to information to all other routers each of its neighbors only when there (RIP). are changes (OSPF/BGP/EGP) Problems: Bandwidth Problems: Step-by-step updates Initial flooding Processing/memory Event driven v. broadcast Static.v. dynamic Routing protocol types W.Buchanan (16)

17 Dest Hops Next Dest Hops Next A 1 B 2 1 x z z A 0 B 1 2 Network A y y W 2 X Network A Dest Hops A 2 B 1 0 Next w y Network Z Network Y Network B Dest Hops A 1 B 0 1 Next x Network B z Example routing W.Buchanan (17)

18 Timing of events A B B E. E. Network Network A A reachable reachable D E E Routing loops B. B. I I can can reach reach Network Network A A in in 3 3 hops hops W Router Z thinks it can reach Network A in 4 hops, as Router W says it can reach it in 3 hops, this overrules the information from Router Y which says it cannot reach Network A Z A. A. Network Network A A unreachable unreachable.. Network Network A A Reachable Reachable via via Router Router W X Y A. A. Network Network A A unreachable unreachable V D. D. Network Network A A reachable reachable Network unreachable Network A W.Buchanan (18)

19 Network 1 becomes unreachable for a short time + LSP (Link state packets) + Topological database (for SPF) Methods Problem Link-state LSP:Network LSP:Network LSP:Network LSP:Network Reachable Reachable Unreachable Unreachable W Z X LSP:Network LSP:Network Unreachable Unreachable LSP Operation 4 Y OSPF OSPF (RF1583) (RF1583) Ver. Ver. Type Type Message Message Len. Len. Router Router ID ID oncerns Area Area ID ID hecksum hecksum Auth. Auth. Type Type Authentication Authentication Each router Processing + Memory builds up a tree Increased processing Increased topology of the power required to amount of subnetworks and find build trees storage memory shortest path for tree Network unreachable arrives after network reachable A change in topology causes updates to all other routers Link-state overview W.Buchanan (19)

20 Ad-hoc Routing Access ontrol W.Buchanan (20)

21 F Infrastructure (uses traditional routing of a fixed network) Ad-hoc routing (uses nodes to route data) W.Buchanan (21)

22 Table-driven. This is where the route is defined by continually updating routing tables. Examples include: DSDV (Destination-Sequenced Distance-Vector). GSR (lusterhead Gateway Switch Routing). WRP (Wireless Routing Protocol). Demand-driven (source-initiated). This is where the source initiates a route for a given connection. Examples include: AODV (Ah-hoc On-Demand Distance Vector). DSR (Dynamic Source Routing). LMR (Lightweight Mobile Routing). TORA (Temporally Ordered Routing Algorithm). ABR (Associativity-based Routing). SSR (Signal Stability Routing). lassifications of Ad-hoc Routing W.Buchanan (22)

23 Table-based Ad-hoc Routing DSDV GSR WRP Access ontrol W.Buchanan (23)

24 Routing table Routing table Routing table Routing table Routing table Routing table Table-based Routing W.Buchanan (24)

25 B F F A A A can see B and D B can see A, D and And so on. D D E E Example of wireless domains W.Buchanan (25)

26 B F F A A A can see B and D B can see A, D and And so on. D D E E Example of wireless domains W.Buchanan (26)

27 Destination Route Next Hop No. of hops H ABH B 2 ABDFH B 3 ABDEFH B 4 ADFH D 2 ADEFH D 3 1 hop B F F A A D D E E Destination-Sequenced Distance-Vector Routing W.Buchanan (27)

28 Destination Route Next Hop No. of hops H ABH B 2 ADFH D 2 Best route is either through B or D 1 hop B F F A A D D E E Destination-Sequenced Distance-Vector Routing W.Buchanan (28)

29 Destination Next Hop No. of hops B B 0 B 1 D D 0 E D 1 F D 1 H B 2 B F F A A D D E E Destination-Sequenced Distance-Vector Routing W.Buchanan (29)

30 Destination Next Hop No. of hops Sequence B B 0 5 B 1 6 D D 0 10 E D 1 1 F D 1 4 H B 2 30 B F F A A D D E E The sequence number Is defined by the destination node, and is used to determine how up-to-date a route is. DSVR (with Sequence Number) W.Buchanan (30)

31 Destination Destination Next Next Hop Hop No. No. of of hops hops Sequence Sequence B B 0 5 B 1 6 D D E D 1 1 F D 1 4 H B B F F A A Full dump of routing table sent at startup or where there is large-scale mobility D D E E NPDU - Network Packet Data Unit DSVR (Full dump of routing table) W.Buchanan (31)

32 Destination Destination Next Next Hop Hop No. No. of of hops hops Sequence Sequence B B 0 5 B 1 6 D D E D 1 1 F D 1 4 H B B F F A A Incremental update of route changes D D E E NPDU - Network Packet Data Unit DSVR (Incremental update) W.Buchanan (32)

33 Destination Destination Next Next Hop Hop No. No. of of hops hops Sequence Sequence B B 0 5 B 1 6 D D E D 1 1 F D 1 4 H B B A A Broadcast of a new route (I). Information sent: D D Dest_Add (I), Hops, Sequence_No (received from I), Sequence_No (of this broadcast) e.g , 0, 10, 22 DSVR (New route discovery) E E I I F F W.Buchanan (33)

34 Destination Destination Next Next Hop Hop No. No. of of hops hops Sequence Sequence B B 0 5 B 1 6 D D E D 1 1 F D 1 4 H B B A A Broadcast of a new route (I). Information sent: D D Dest_Add (I), Hops, Sequence_No (received from I), Sequence_No (of this broadcast) e.g , 0, 10, xx DSVR (New route discovery) E E I I F F W.Buchanan (34)

35 Destination Destination Next Next Hop Hop No. No. of of hops hops Sequence Sequence B B 0 5 B 1 6 D D E D 1 1 F D 1 4 H B B A A Broadcast of a new route (I). Information sent: D D Dest_Add (I), Hops, Sequence_No (received from I), Sequence_No (of this broadcast) e.g , 0, 10, xx DSVR (New route discovery) E E I I F F W.Buchanan (35)

36 Destination Destination Next Next Hop Hop No. No. of of hops hops Sequence Sequence B B 0 5 :: :: H B II D B F F A A , 0, 11, xx This will be ignored as it has the sequence number is lower than a previous update. I I D D E E , 0, 10, xx I I DSVR (New route discovery) W.Buchanan (36)

37 B F F A A D D E E lusterhead Gateway Switch Routing (GSR) W.Buchanan (37)

38 Gateway node is used to route data between clusters luster 2 I I B F F luster 4 A A luster 1 One node is elected a cluster head (normally based on geographical knowledge) D D E E luster 3 GSR W.Buchanan (38)

39 R R luster 2 I I QQ S S T T JJ K B P P U U A A L L luster 1 N N D D OO MM E E F F luster 3 luster 4 luster heads are responsible for the clusters and locating clusters outwith its cluster. A node which can be contacted by two cluster heads is elected as the gateway. SGR W.Buchanan (39)

40 R R luster 2 I I QQ S S T T JJ K B P P N U A L D luster 1 For example if K wishes to sent to Q: 1. K sends data packet to its cluster head (A) OO MM E E F F luster 3 luster 4 SGR W.Buchanan (40)

41 R R luster 2 I I QQ S S T T JJ K B P P N U F A L D MM OO luster 1 E luster 3 For example if K wishes to sent to Q: 2. luster head (A) sends the data packet to the required gateway (B) luster 4 SGR W.Buchanan (41)

42 R R luster 2 I I QQ S S T T JJ K B P P N U F A L D MM OO luster 1 E luster 3 For example if K wishes to sent to Q: 3. The gateway node (B) forwards the data packet to the cluster head (I) luster 4 SGR W.Buchanan (42)

43 R R luster 2 I I QQ S S T T JJ K B P P N U F A L D MM OO luster 1 E luster 3 For example if K wishes to sent to Q: 4. luster head forwards the data packet to the required node (Q) luster 4 SGR W.Buchanan (43)

44 luster member table Dest U R L :: Dest luster head A I A R R luster 2 I I QQ S S T T JJ K B P P U U A A L L luster 1 Each node stores a luster Member Table which is broadcast by each node at various times N N D D OO MM E E F F luster 3 luster 4 SGR - luster Member Table W.Buchanan (44)

45 Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. Update Messages: Dest, Distance, Predecessor of the destination, Nodes to ack. update B Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. I I opy of routing table F A D E MRT stores the required updates for an update message, and contains: Seq_No_of_Update_Message Retransmission_ounter Acknowledgement_flag List_Of_Updates Wireless Routing Protocol (WRP) W.Buchanan (45)

46 Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. B Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. I I A A Update Messages: Dest, Distance, Predecessor of the destination, Nodes to ack. update Once received, a node may forward the update message to its own neighbours D D E E F F Wireless Routing Protocol (WRP) W.Buchanan (46)

47 Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. B Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. I I A A Update Messages: Dest, Distance, Predecessor of the destination, Nodes to ack. update D D Updates thus propagate throughout the network E E F F Wireless Routing Protocol (WRP) W.Buchanan (47)

48 Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. Distance Distance Table. Table. Routing Routing Table. Table. Link-cost Link-cost Table. Table. Message Message retransmission retransmission Table. Table. I I A A HELLO D D B HELLO HELLO HELLO E E HELLO Nodes determine their neighbours by listening to HELLO messages, which are sent out at regular intervals. A lack of a HELLO message means that the node have gone. F F WRP - HELLO messages W.Buchanan (48)

49 Source-Initiated Ad-hoc Routing AODV DSR TORA ABR Access ontrol W.Buchanan (49)

50 B F F A A RREQ (Route Request) D D I I E E Ad-hoc On-demand Distance Vector (AODV) W.Buchanan (50)

51 Routing Table New route added (from A) B F F A A D D RREQ (Route Request) I I E E AODV - Route Request W.Buchanan (51)

52 Routing Table New route added (from B) B F F A A D D RREQ (Route Request) I I E E AODV W.Buchanan (52)

53 Routing Table New route confirmed B Routing Table New route confirmed F F A A D D RREP (Route Reply) I I E E AODV - Route Reply W.Buchanan (53)

54 Routing Table New route confirmed B Routing Table New route confirmed F F A A D D RREP (Route Reply) I I E E AODV - Route Reply W.Buchanan (54)

55 HELLO B HELLO HELLO HELLO A A D D HELLO Along with RREQ and RREP, there are HELLO broadcasts which inform nodes as to their neighbours I I E E F F AODV - HELLO broadcasts W.Buchanan (55)

56 B F F A A D D I I E E Dynamic Source Routing (DSR) W.Buchanan (56)

57 Route Request Destination: H Route: A ID B F F A A Route Request Destination: H Route: A ID D D I I E E DSR - Route Discovery W.Buchanan (57)

58 A A D D B Route Request Destination: H Route: A, D ID Route Request Destination: H Route: A, B ID Route Request Destination: H Route: A, D ID I I E E F F DSR - Route Discovery W.Buchanan (58)

59 Route Request Destination: H Route: A, B, ID A A D D B E E Route Request Destination: H Route: A, D, I ID I I F F Route Request Destination: H Route: A, D, E ID DSR - Route Discovery W.Buchanan (59)

60 Routing Table New route confirmed Route Reply Destination: H Route: A, B,, H ID B Route Reply Destination: H Route: A, B,, H ID Route Reply Destination: H Route: A, B,, H ID F F A A D D I I E E DSR - Route Reply W.Buchanan (60)

61 The route is kept alive with acknowledgements of data received Ack B Ack Ack F F A A D D I I E E DSR - Keeping the route alive W.Buchanan (61)

62 Nodes will rip-up the route on receiving the error packets Error packet Destination not available B F F A A D D I I E E DSR - Route Reply W.Buchanan (62)

63 B F F A A D D I I E E A A B B D D D D I I E F F F First a Directed Acyclic Graph (DEG) is drawn A DEG contains no cycles, thus it is not possible to start from one position and end at the same place Temporally Ordered Routing Algorithm W.Buchanan (63)

64 A major problem in wireless networks is that nodes can be mobile and highly mobile nodes can loose the route W.Buchanan (64)

65 Association Table Node B Node D B F F A A D D The association table defines the possible stability of the route. High association typically equals low mobility I I E E Associated-Based Routing (ABR) W.Buchanan (65)

66 Route Request Destination: H Association: A-B (val) B Route Request Destination: H Association: A-B (val) B- (val) Route Request Destination: H Association: A-B (val) B- (val) -H (val) A A Route Request Destination: H Association: A-D (val) D D The destination can choice which route is the most stable. If they have the same associativity then a hop count is used. I I E E F F Route Request Destination: H Association: A-D (val) D-E (val) E-F (val) F-H (val) ABR W.Buchanan (66)

67 Stability Table Signal Strength, Location B F F A A D D I I E E Signal Stability Routing W.Buchanan (67)

68 Agent-based, Ah-hoc, On-demand routing - N.Migas, PhD Student, So - G.Sinclair, BEng (Hons), SEng, So W.Buchanan (68)

69 Wireless Domain A Wireless Domain Wireless Domain B Wireless Domains W.Buchanan (69)

70 Wireless Domain Wireless Domain A Wireless Domain B Routing Over Wireless Domains W.Buchanan (70)

71 Hosts Fixed network Wireless domains Bridging Wireless Domains W.Buchanan (71)

72 Routing mechanism between wireless domains (Defining metrics for different traffic types). Performance tests on hosts, especially related to routing. ompatibility of devices (Window, UNIX, Windows E, and so on). Generation of routing tables. Definition of QoS for connections. How agents are used (Static or Mobile?). Tests: Network performance. onnectivity. Memory buffering. Processor performance. Protocol performance. And so on. Issues? W.Buchanan (72)

73 Wireless Domain A Device running a proxy server Wireless Domain B Using a Proxy for Routing W.Buchanan (73)

74 Agents? - Goal-oriented programs Mobile Agent - an migrate code and data between hosts - an thaw its execution, serialise itself, and the start on another machine Static Agent - Stays local to the machine - an have high integration with host Mobile and Static Agents W.Buchanan (74)

75 Agents? - Goal-oriented programs Mobile Agent - Gathers information on hosts Static Agent - Runs routing tests, such as Processor tests, network tests, and so on. Mobile and Static Agents (How they are used in this research) W.Buchanan (75)

76 Routing Agent Database Agent Itinerary Agent Test Agent Database Agent Test Agent Mobile Agent Database Agent Test Agent Database Agent Test Agent Mobile and Static Agents (How they are used in this research) W.Buchanan (76)

77 Many programs now use client-server elements to their operation. The following sections show how Java and Visual Basic implement sockets. Most of the connections on the Internet are based on these sockets. Visual Basic is event-driven where an event occurs from the keyboard or from the network connection. Unfortunately Java does not quite allow this, and we must use threads to allow one thread to monitor the keyboard, and another to monitor the network connection. Socket programming W.Buchanan (77)

78 lient/server programming using threads System.in client Thread1 Thread1 Thread2 Thread2 System.out server W.Buchanan (78)

79 Server program public class server extends Thread { public static void main( String arg[]) throws IOException { int port1=1000, debug=0; if (arg.length>=1) port1=integer.parseint(arg[0]); // receiving port System.out.println("Using incoming port: " + port1 ); try { System.out.println("Listening..."); ServerSocket sock = new ServerSocket(port1); Socket sock1 = sock.accept(); System.out.println("Accepting"); System.out.println("Input : " + sock1.getinetaddress() + " Port : " + sock1.getport()); System.out.print("reating Write1 Thread..."); writethread1 w1thd = new writethread1(sock1); writethread2 w2thd = new writethread2(sock1); w1thd.start(); w2thd.start(); W.Buchanan (79)

80 lient program public class client extends Thread { public static void main( String arg[]) throws IOException { String addr=" "; int port1=1000; if (arg.length>=1) addr=arg[0]; // destination if (arg.length>=2) port1=integer.parseint(arg[1]); // receiving port System.out.println("Using incoming port: " + port1 + " Destination address : " + addr); try { Socket sock1 = new Socket(addr,port1); System.out.println("Input : " + sock1.getinetaddress() + " Port : " + sock1.getport()); System.out.print("reating Write1 Thread..."); writethread1 w1thd = new writethread1(sock1); writethread2 w2thd = new writethread2(sock1); w1thd.start(); w2thd.start(); W.Buchanan (80)