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Information and Communication engineering (ICE) MUT ITEC4610 Network Switching and Routing ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร.

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Presentation on theme: "Information and Communication engineering (ICE) MUT ITEC4610 Network Switching and Routing ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร."— Presentation transcript:

1 Information and Communication engineering (ICE) MUT ITEC4610 Network Switching and Routing ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร (ICE) MUT Email: prawit@mut.ac.thprawit@mut.ac.th ห้องทำงาน : F402 เบอร์โทรศัพท์ที่ทำงาน : (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่ : 065343850

2 Information and Communication engineering (ICE) MUT Class V Routing Algorithms, RIPv1&RIPv2 ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร (ICE) MUT Email: prawit@mut.ac.thprawit@mut.ac.th ห้องทำงาน : F402 เบอร์โทรศัพท์ที่ทำงาน : (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่ : 065343850

3 Information and Communication engineering (ICE) MUT หัวข้อที่จะบรรยาย  Routing Algorithm –Distance-vector routing –Link state routing RIPv1 RIPv2

4 Information and Communication engineering (ICE) MUT IP components สร้างได้ อย่างไร ? ไว้ทำอะไร สร้างได้ อย่างไร ? ไว้ทำอะไร ? สร้างได้ อย่างไร ? ไว้ทำอะไร ?

5 Information and Communication engineering (ICE) MUT Routing protocol Define how routers exchange network –What type of information –The format of information –When to exchange –Which router to exchange information with RIP, OSPF,BGP, IGRP,EIGRP etc.

6 Information and Communication engineering (ICE) MUT Routing algorithm To choose or compute a route based on the available network information A routing algorithm is defined by –The type of network information exchanges –Which router to exchange with –Method to compute the routes Distance vector routing, Link state routing, Diffusing update algorithm (DUAL) etc.

7 Information and Communication engineering (ICE) MUT Routing Algorithm classification Global or decentralized information? Global: all routers have complete topology, link cost info “link state” algorithms Decentralized: router knows physically- connected neighbors, link costs to neighbors iterative process of computation, exchange of info with neighbors “distance vector” algorithms Static or dynamic? Static: routes change slowly over time Dynamic: routes change more quickly –periodic update –in response to link cost changes

8 Information and Communication engineering (ICE) MUT Upon completion you will be able to: Distinguish between intra and interdomain routing Understand distance vector routing and RIP Understand link state routing Objectives Unicast Routing Protocols: RIP

9 Information and Communication engineering (ICE) MUT Routing inside an autonomous system is referred to as intradomain routing. Routing between autonomous systems is referred to as interdomain routing. INTRA- AND INTERDOMAIN ROUTING

10 Information and Communication engineering (ICE) MUT Autonomous systems

11 Information and Communication engineering (ICE) MUT Popular routing protocols

12 Information and Communication engineering (ICE) MUT Routing in the Internet Path- or distance- vector protocols Link-state protocols Inter-domain (policy) BGP Intra-domain (performanc e) RIP, IGRP, EIGRP(advan ce DV) OSPF, IS-IS

13 Information and Communication engineering (ICE) MUT In distance vector routing, the least cost route between any two nodes is the route with minimum distance. In this protocol each node maintains a vector (table) of minimum distances to every node The topics discussed in this section include: InitializationSharingUpdating When to Share Two-Node Loop Instability Three-Node Instability DISTANCE VECTOR ROUTING

14 Information and Communication engineering (ICE) MUT Distance vector routing tables

15 Information and Communication engineering (ICE) MUT ขบวนการสร้าง routing table Initialization Sharing Updating

16 Information and Communication engineering (ICE) MUT Initialization of tables in distance vector routing

17 Information and Communication engineering (ICE) MUT Initialization ได้มาจากที่ไหน –ICMP - Router Solicitation - Router Advertisement

18 Information and Communication engineering (ICE) MUT In distance vector routing, each node shares its routing table with its immediate neighbors periodically and when there is a change. Note:

19 Information and Communication engineering (ICE) MUT Updating in distance vector routing of A

20 Information and Communication engineering (ICE) MUT Trigger Updates A cost update distributed immediately in response to a detected change in the cost estimate for a route to destination May delay trigger updates for a short time The trigger updates contain information about only changed routes –RIP

21 Information and Communication engineering (ICE) MUT Holddowns Prevent the reinstatement of old routes When a router moves from its routing table a route to a particular destination, it invokes a holddown that disables acceptance of new routes to this detination for a specified time interval Disadvantage –Increase the time for routers to learn the correct new routes

22 Information and Communication engineering (ICE) MUT การแสดงในรูปแบบของเวกเตอร์ Bellman-Ford algorithm on a number of hops h

23 Information and Communication engineering (ICE) MUT ตัวอย่างการคำนวน i/j123 1015 2102 3520 D ij ( 1)

24 Information and Communication engineering (ICE) MUT ตัวอย่างการคำนวน i/j123 1013 2102 3320 D ij ( 2)

25 Information and Communication engineering (ICE) MUT ตัวอย่างการคำนวน Node 1’s routing Table ToCostNext Node 21direct Node 32Node 2 Node 45Node 2 Node 56Node 2

26 Information and Communication engineering (ICE) MUT Two-node instability

27 Information and Communication engineering (ICE) MUT Defining Infinity

28 Information and Communication engineering (ICE) MUT Split Horizon

29 Information and Communication engineering (ICE) MUT Problem of Split Horizon Node A could not guess that this is due to the split horizon strategy or because B has not received any news about X recently

30 Information and Communication engineering (ICE) MUT Split Horizon and Poison Reverse

31 Information and Communication engineering (ICE) MUT Three-node instability

32 Information and Communication engineering (ICE) MUT Defining Infinity

33 Information and Communication engineering (ICE) MUT Loop-Free Distance Vector Routing Distributing enough information in update messages --> quickly detect, no prevent routing loop Controlling the order in which nodes distribute update messages and compute routes in response to an increase in link cost  Prevent loop but require –A significant number of message exchanges –Slow convergence Refs –J. J. Garcia-Luna-Aceves: A Minimum-Hop Routing Algorithm Based on Distributed Information. Computer Networks 16: 367-382 (1989) –DUAL  EIGRP

34 Information and Communication engineering (ICE) MUT คำถาม ?

35 Information and Communication engineering (ICE) MUT แบบฝึกหัดลองทำดู Node 2’s routing Table ToCostNext Node 1 Node 3 Node 4 Node 5

36 Information and Communication engineering (ICE) MUT เฉลย Node 2’s routing Table ToCostNext Node 11direct Node 32direct Node 44Node 3 Node 55Node 3

37 Information and Communication engineering (ICE) MUT แบบฝึกหัดลองทำดู เป็นการบ้าน จงแสดงการคำนวนหา node 1’ routing table ใช้ Bellman-Ford’s algorithm

38 Information and Communication engineering (ICE) MUT In link state routing, if each node in the domain has the entire topology of the domain, the node can use Dijkstra’s algorithm to build a routing table. The topics discussed in this section include: Building Routing Tables LINK STATE ROUTING

39 Information and Communication engineering (ICE) MUT Concept of link state routing Each router knows network topology

40 Information and Communication engineering (ICE) MUT Link state knowledge

41 Information and Communication engineering (ICE) MUT Dijkstra algorithm

42 Information and Communication engineering (ICE) MUT Example of formation of shortest path tree

43 Information and Communication engineering (ICE) MUT Table 14.1 Routing table for node A

44 Information and Communication engineering (ICE) MUT การแสดงในรูปแบบของเวกเตอร์

45 Information and Communication engineering (ICE) MUT ตัวอย่าง Find A’s routing table no de 12345 10523∞ 2504∞3 3240∞4 43∞∞0∞ 5∞34∞0 d ij

46 Information and Communication engineering (ICE) MUT ตัวอย่าง

47 Information and Communication engineering (ICE) MUT ตัวอย่าง

48 Information and Communication engineering (ICE) MUT ตัวอย่าง

49 Information and Communication engineering (ICE) MUT ตัวอย่าง

50 Information and Communication engineering (ICE) MUT สรุปเป็นตาราง StepPB (cost, NH) C (cost, NH) D (cost, NH) E (cost, NH) 0A5,A2,A3,A∞ 1AC5,A3,A6,C 2ACD5,A6,C 3ACDB6,C 4ACDBE

51 Information and Communication engineering (ICE) MUT Comparison of LS and DV algorithms Message complexity LS: with n nodes, E links, O(nE) msgs sent DV: exchange between neighbors only –convergence time varies Speed of Convergence LS: O(n 2 ) algorithm requires O(nE) msgs –may have oscillations DV: convergence time varies –may be routing loops –count-to-infinity problem Robustness: what happens if router malfunctions? LS: –node can advertise incorrect link cost –each node computes only its own table DV: –DV node can advertise incorrect path cost –each node’s table used by others error propagate thru network

52 Information and Communication engineering (ICE) MUT คำถาม ?

53 Information and Communication engineering (ICE) MUT แบบฝึกหัดลองทำดู Node 2’s routing Table ToCostNext Node 1 Node 3 Node 4 Node 5

54 Information and Communication engineering (ICE) MUT เฉลย j/i12345 101 ∞∞ 7 2102 ∞ 8 3 ∞ 202 ∞ 4 ∞∞ 201 578 ∞ 10 d ji

55 Information and Communication engineering (ICE) MUT เฉลย j/i12345 101 ∞∞ 7 2102 ∞ 8 3 ∞ 202 ∞ 4 ∞∞ 201 578 ∞ 10 d ji

56 Information and Communication engineering (ICE) MUT เฉลย j/i12345 101 ∞∞ 7 2102 ∞ 8 3 ∞ 202 ∞ 4 ∞∞ 201 578 ∞ 10 d ji

57 Information and Communication engineering (ICE) MUT เฉลย j/i12345 101 ∞∞ 7 2102 ∞ 8 3 ∞ 202 ∞ 4 ∞∞ 201 578 ∞ 10 d ji

58 Information and Communication engineering (ICE) MUT สรุปเป็นตาราง StepPNode 2 (cost, NH) Node 3 (cost, NH) Node 4 (cost, NH) Node 5 (cost, NH) 011,1∞∞7,1 1123,1∞7,1 21235,37,1 312346,4 412345

59 Information and Communication engineering (ICE) MUT แบบฝึกหัดลองทำดู จงแสดงการคำนวนหา node 1’ routing table ใช้ Dijkstra’s algorithm

60 Information and Communication engineering (ICE) MUT เฉลย สรุปเป็นตาราง StepPNode 2 (cost, NH) Node 3 (cost, NH) Node 4 (cost, NH) Node 5 (cost, NH) Node 5 (cost, NH) 0 1 2 3 4 5

61 Information and Communication engineering (ICE) MUT The Routing Information Protocol (RIP) is an intradomain routing protocol used inside an autonomous system. It is a very simple protocol based on distance vector routing. The topics discussed in this section include: RIP Message Format Requests and Responses Timers in RIP RIP Version 2 Encapsulation RIP

62 Information and Communication engineering (ICE) MUT Example of a domain using RIP

63 Information and Communication engineering (ICE) MUT RIP message format Command : 1, request, 2 response Version : version 1 or version 2 Family : Define family of the protocol used ex. 2 for TCP/IP Network address : The address of destination address Distance :Hop count to the destination networ

64 Information and Communication engineering (ICE) MUT Request messages

65 Information and Communication engineering (ICE) MUT Response Message -Command field = 1 -Solicited response is sent only answer to request -Unsolicited response is sent periodically, every 30 second

66 Information and Communication engineering (ICE) MUT Figure 14.11 shows the update message sent from router R1 to router R2 in Figure 14.8. The message is sent out of interface 130.10.0.2. See Next Slide The message is prepared with the combination of split horizon and poison reverse strategy in mind. Router R1 has obtained information about networks 195.2.4.0, 195.2.5.0, and 195.2.6.0 from router R2. When R1 sends an update message to R2, it replaces the actual value of the hop counts for these three networks with 16 (infinity) to prevent any confusion for R2. The figure also shows the table extracted from the message. Router R2 uses the source address of the IP datagram carrying the RIP message from R1 (130.10.02) as the next hop address. Example 1

67 Information and Communication engineering (ICE) MUT Solution to Example 1 it replaces the actual value of the hop counts for these three networks with 16 (infinity) to prevent any confusion for R2 -- Split Horizon and Poison Reverse

68 Information and Communication engineering (ICE) MUT RIP timers - Periodic timer = Controls the advertising of regular update message - Expiration = Governs the validity of a route - Garbage Collection= When to purge a route from the routing table -This timer allows neighbors to become aware of the invalidity of the route prior to purging

69 Information and Communication engineering (ICE) MUT A routing table has 20 entries. It does not receive information about five routes for 200 s. How many timers are running at this time? Solution The 21 timers are listed below: Periodic timer: 1 Expiration timer: 20 − 5 = 15 Garbage collection timer: 5 RIP timers

70 Information and Communication engineering (ICE) MUT RIP version 2 format Route tag –Carries information such as autonomous system number Subnet mask –Carries subnet mask or prefix Next-hop address –Carries the address of next hop

71 Information and Communication engineering (ICE) MUT Authentication

72 Information and Communication engineering (ICE) MUT Multicasting RIP Version 1 uses broadcasting RIP Version 2 uses the all router multicast address

73 Information and Communication engineering (ICE) MUT RIP uses the services of UDP on well-known port 520. Note:

74 Information and Communication engineering (ICE) MUT RIPv1 Distance vector protocol Uses UDP port 520 Classlfull protocol Metric is router hop count Maximum hop count is 15;infinite (unreachable) routes have a metric of 16 Periodic updates sent every 30 seconds to multicast address 224.0.0.9 25 routes per RIP messages (24 if uses authentication) Implement split horizon with poison reverse Implements triggered updates No support Authentication Subnet mask included in route entry Administrative of distance for RIPv2 is 120 –A rating of the trustworthiness of a routing information source. In Cisco routers, administrative distance is expressed as a numerical value between 0 and 255. The higher the value, the lower the trustworthiness rating.

75 Information and Communication engineering (ICE) MUT RIPv2 Distance vector protocol Uses UDP port 520 Classless protocol Support VLSM Metric is router hop count Maximum hop count is 15;infinite (unreachable) routes have a metric of 16 Periodic updates sent every 30 seconds to multicast address 224.0.0.9 25 routes per RIP messages (24 if uses authentication) Implement split horizon with poison reverse Implements triggered updates Subnet mask included in route entry Administrative of distance for RIPv2 is 120

76 Information and Communication engineering (ICE) MUT IP components สร้างได้ อย่างไร ?

77 Information and Communication engineering (ICE) MUT RIP Table processing RIP routing tables managed by application- level process called route-d (daemon) advertisements sent in UDP packets, periodically repeated physical link network forwarding (IP) table Transprt (UDP) routed physical link network (IP) Transprt (UDP) routed forwarding table

78 Information and Communication engineering (ICE) MUT คำถาม ?

79 Information and Communication engineering (ICE) MUT Summary Distance Vector routing Link State Routing RIPv1 & RIPv2

80 Information and Communication engineering (ICE) MUT Homeworks เตรียมบรรยายเรื่อง 2-3 คนต่อ 1 กลุ่ม – เปรียบเทียบ IPv4 และ IPv6 หรือ – เปรียบเทียบ ICMP4 และ ICMP6 หรือ –Mobile IPv4 หรือ –Mobile IPv6 ใช้ Microsoft PowerPoint ในการบรรยาย บรรยายกลุ่มละ 10-15 นาที ถามตอบ 5 นาที่ เก็บ 5 % บรรยาย 1 กรกฎาคม 2549 เวลา 16.00 ( ต้องตรง เวลา )


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