networks protocols
play

Networks & Protocols INF566 - X2010 - 2012 Lecture 3 - - PowerPoint PPT Presentation

Nov 05, 2022 •482 likes •2.15k views

Networks & Protocols INF566 - X2010 - 2012 Lecture 3 - Enterprise Grade Routing - OSPF thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 1 Intro, kick-off, objectives and motivation (Thomas)

  1. Some Taxonomy thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  2. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 Router IDs selected independent of interface addresses 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  3. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 Router IDs selected independent of interface addresses Links 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  4. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 Address 10.1.5/24 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  5. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 4 2 1 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 3 2 3 1 Address Cost - called “Metric” 5 10.1.5/24 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  6. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 4 2 1 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 3 2 3 1 Address Cost - called “Metric” Metric in range [0 , 2 16 ] 5 (Metric can be asymmetric) 10.1.5/24 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  7. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 .1 4 .2 2 1 .2 .4 .4 .6 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of .1 .2 .4 .6 interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 3 2 3 1 Address Cost - called “Metric” .3 .5 Metric in range [0 , 2 16 ] 5 (Metric can be asymmetric) .3 .3 .5 .5 10.1.5/24 Interfaces 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  8. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 .1 4 .2 2 1 .2 .4 .4 .6 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of .1 .2 .4 .6 interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 3 2 3 1 Address Cost - called “Metric” .3 .5 Metric in range [0 , 2 16 ] 5 (Metric can be asymmetric) .3 .3 .5 .5 10.1.5/24 Interfaces 10.10.10.3 10.10.10.5 Address thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  9. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 .1 4 .2 2 1 .2 .4 .4 .6 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of .1 .2 .4 .6 interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 3 2 3 1 Address Cost - called “Metric” .3 .5 Metric in range [0 , 2 16 ] 5 (Metric can be asymmetric) .3 .3 .5 .5 10.1.5/24 Interfaces 10.10.10.3 10.10.10.5 Address From the “link prefix” thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  10. Some Taxonomy 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 .1 4 .2 2 1 .2 .4 .4 .6 Router IDs selected 10.1.1/24 10.1.4/24 10.1.7/24 independent of .1 .2 .4 .6 interface addresses 10.1.2/24 10.1.8/24 Links 10.1.3/24 10.1.6/24 3 2 3 1 Address Cost - called “Metric” .3 .5 Metric in range [0 , 2 16 ] 5 (Metric can be asymmetric) .3 .3 .5 .5 10.1.5/24 Interfaces 10.10.10.3 10.10.10.5 Address From the “link prefix” In this case, all .X are the same thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 10

  11. Link State Advertisements 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 .1 4 .2 2 1 .2 .4 .4 .6 10.1.1/24 10.1.4/24 10.1.7/24 .1 .2 .4 .6 10.1.2/24 10.1.8/24 10.1.3/24 10.1.6/24 3 2 3 1 .3 .5 5 .3 .3 .5 .5 10.1.5/24 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 11

  12. Link State Advertisements 10.10.10.1 10.10.10.2 .1 4 .2 2 .2 10.1.1/24 10.1.4/ .1 .2 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 12

  13. Link State Advertisements 10.10.10.1 10.10.10.2 .1 4 .2 2 .2 10.1.1/24 10.1.4/ .1 .2 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  14. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 10.1.1/24 10.1.4/ .1 .2 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  15. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 Link State ID : 10.10.10.1 = Router ID 10.1.1/24 10.1.4/ .1 .2 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  16. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 Link State ID : 10.10.10.1 = Router ID 10.1.1/24 10.1.4/ Advertising Router: 10.10.10.1 = Router ID .1 .2 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  17. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 Link State ID : 10.10.10.1 = Router ID 10.1.1/24 10.1.4/ Advertising Router: 10.10.10.1 = Router ID .1 .2 Number of links: 3 = 2 links plus router itself 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  18. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 Link State ID : 10.10.10.1 = Router ID 10.1.1/24 10.1.4/ Advertising Router: 10.10.10.1 = Router ID .1 .2 Number of links: 3 = 2 links plus router itself 10.1.2/24 10.1.3/24 Description of Link 1: Link ID = 10.1.1.1, Metric = 4 3 2 Description of Link 2: Link ID = 10.1.2.1, Metric = 3 .3 Description of Link 3: Link ID = 10.10.10.1, Metric = 0 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  19. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 Link State ID : 10.10.10.1 = Router ID 10.1.1/24 10.1.4/ Advertising Router: 10.10.10.1 = Router ID .1 .2 Number of links: 3 = 2 links plus router itself 10.1.2/24 10.1.3/24 Description of Link 1: Link ID = 10.1.1.1, Metric = 4 3 2 Description of Link 2: Link ID = 10.1.2.1, Metric = 3 .3 Description of Link 3: Link ID = 10.10.10.1, Metric = 0 5 .3 .3 Other stuff: 10.1.5/ checksum, sequence number, .... 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  20. Link State Advertisements 10.10.10.1 10.10.10.2 • LSA of router 10.10.10.1: .1 4 .2 2 .2 Link State ID : 10.10.10.1 = Router ID 10.1.1/24 10.1.4/ Advertising Router: 10.10.10.1 = Router ID .1 .2 Number of links: 3 = 2 links plus router itself 10.1.2/24 10.1.3/24 Description of Link 1: Link ID = 10.1.1.1, Metric = 4 3 2 Description of Link 2: Link ID = 10.1.2.1, Metric = 3 .3 Description of Link 3: Link ID = 10.10.10.1, Metric = 0 5 .3 .3 Other stuff: 10.1.5/ checksum, sequence number, .... 10.10.10.3 Each router sends its LSA to all routers in the network (using a method called reliable flooding) thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 13

  21. LSDB 10.10.10.1 10.10.10.2 .1 4 .2 2 .2 10.1.1/24 10.1.4/ .1 .2 10.1.2/24 10.1.3/24 3 2 .3 5 .3 .3 10.1.5/ 10.10.10.3 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 14

  22. 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 .1 4 .2 2 1 .2 .4 .4 .6 LSDB 10.1.1/24 10.1.4/24 10.1.7/24 .1 .2 .4 .6 10.1.2/24 10.1.8/24 10.1.3/24 10.1.6/24 3 2 3 1 Each router has a .3 .5 database which 5 .3 .3 .5 .5 contains the LSAs from all other routers 10.1.5/24 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 15

  23. LSDB • The collection of all LSAs is called the link-state database • Each router has and identical link-state database • Useful for debugging: complete network description • When neighboring routers discover each other for the first time, they will exchange their link-state databases • The link-state databases are synchronized using reliable flooding thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 16

  24. OSPF Packet Format OSPF packets are not carried as UDP payload! OSPF has its own IP protocol number: 89 TTL: set to 1 (in most cases) Destination IP: neighbor’s IP address or 224.0.0.5 (ALLSPFRouters) or 224.0.0.6 (AllDRouters) thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 17

  25. OSPF Header Format thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  26. OSPF Header Format 2: current version is OSPF V2 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  27. OSPF Header Format 2: current version is OSPF V2 Message types: 1: Hello (tests reachability) 2: Database description 3: Link Status request 4: Link state update 5: Link state acknowledgement thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  28. OSPF Header Format 2: current version is OSPF V2 ID of the Area Message types: from which the 1: Hello (tests reachability) packet originated 2: Database description 3: Link Status request 4: Link state update 5: Link state acknowledgement thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  29. OSPF Header Format 2: current version is OSPF V2 ID of the Area Message types: from which the 1: Hello (tests reachability) packet originated 2: Database description 3: Link Status request 4: Link state update 5: Link state acknowledgement Standard IP checksum taken over entire packet thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  30. OSPF Header Format 2: current version is OSPF V2 ID of the Area Message types: from which the 1: Hello (tests reachability) packet originated 2: Database description 3: Link Status request 4: Link state update 0: no authentication 5: Link state acknowledgement 1: Cleartext password 2: MD5 checksum Standard IP checksum taken (added to end over entire packet packet) thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  31. OSPF Header Format 2: current version is OSPF V2 ID of the Area Message types: from which the 1: Hello (tests reachability) packet originated 2: Database description 3: Link Status request 4: Link state update 0: no authentication 5: Link state acknowledgement 1: Cleartext password 2: MD5 checksum Standard IP checksum taken (added to end over entire packet packet) Authentication passwd = 1: 64 cleartext password Authentication passwd = 2: 0x0000 (16 bits) Prevents replay KeyID (8 bits) attacks Length of MD5 checksum (8 bits) Nondecreasing sequence number (32 bits) thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 18

  32. OSPF LSA Format LSA Header Link 1 Link 2 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 19

  33. Know Thy Neighbors thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 20

  34. Know Thy Neighbors • Routers multicasts OSPF Hello packets on all OSPF- enabled interfaces. thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 20

  35. Know Thy Neighbors • Routers multicasts OSPF Hello packets on all OSPF- enabled interfaces. • If two routers share a link, they can become neighbors, and establish an adjacency OSPF HELLO 10.10.10.1 10.10.10.2 Scenario: OSPF HELLO: I heard 10.10.10.2 Router 10.1.10.2 restarts thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 20

  36. Know Thy Neighbors • Routers multicasts OSPF Hello packets on all OSPF- enabled interfaces. • If two routers share a link, they can become neighbors, and establish an adjacency OSPF HELLO 10.10.10.1 10.10.10.2 Scenario: OSPF HELLO: I heard 10.10.10.2 Router 10.1.10.2 restarts DBx • After becoming adjacent, routers exchange their link state databases thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 20

  37. Database Exchange OSPF HELLO 10.10.10.1 10.10.10.2 Scenario: OSPF HELLO: I heard 10.10.10.2 Router 10.1.10.2 restarts DBx thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 21

  38. Scenario: Database Exchange Router 10.10.10.2 restarts OSPF HELLO 10.10.10.1 10.10.10.2 OSPF HELLO: I heard 10.10.10.2 DBx thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 22

  39. Scenario: Database Exchange Router 10.10.10.2 restarts OSPF HELLO 10.10.10.1 10.10.10.2 Discovery of OSPF HELLO: I heard 10.10.10.2 adjacency DBx After neighbors are discovered the nodes exchange their databases thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 22

  40. Scenario: Database Exchange Router 10.10.10.2 restarts OSPF HELLO 10.10.10.1 10.10.10.2 Discovery of OSPF HELLO: I heard 10.10.10.2 adjacency DBx After neighbors are discovered the nodes exchange their databases Database Description: Sequence = X Send empty Database Description thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 22

  41. Scenario: Database Exchange Router 10.10.10.2 restarts OSPF HELLO 10.10.10.1 10.10.10.2 Discovery of OSPF HELLO: I heard 10.10.10.2 adjacency DBx After neighbors are discovered the nodes exchange their databases Database Description: Sequence = X Send empty Sends database Database description. Database Description: Sequence = X, Description (description only 5 LSA Headers = { contains LSA Router-LSA, 10.10.10.1, 0x80000006 headers) Router-LSA, 10.10.10.3, 0x80000007 Router-LSA, 10.10.10.4, 0x8000003a Router-LSA, 10.10.10.5, 0x80000038 Router-LSA, 10.10.10.6, 0x80000005 } thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 22

  42. Scenario: Database Exchange Router 10.10.10.2 restarts OSPF HELLO 10.10.10.1 10.10.10.2 Discovery of OSPF HELLO: I heard 10.10.10.2 adjacency DBx After neighbors are discovered the nodes exchange their databases Database Description: Sequence = X Send empty Sends database Database description. Database Description: Sequence = X, Description (description only 5 LSA Headers = { contains LSA Router-LSA, 10.10.10.1, 0x80000006 headers) Router-LSA, 10.10.10.3, 0x80000007 Router-LSA, 10.10.10.4, 0x8000003a Router-LSA, 10.10.10.5, 0x80000038 Router-LSA, 10.10.10.6, 0x80000005 Database } Description of 10.10.10.2 Database Description: Sequence = X+1 1 LSA Headers = { Router-LSA, 10.10.10.2, 0x80000005 } thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 22

  43. Scenario: Database Exchange Router 10.10.10.2 restarts OSPF HELLO 10.10.10.1 10.10.10.2 Discovery of OSPF HELLO: I heard 10.10.10.2 adjacency DBx After neighbors are discovered the nodes exchange their databases Database Description: Sequence = X Send empty Sends database Database description. Database Description: Sequence = X, Description (description only 5 LSA Headers = { contains LSA Router-LSA, 10.10.10.1, 0x80000006 headers) Router-LSA, 10.10.10.3, 0x80000007 Router-LSA, 10.10.10.4, 0x8000003a Router-LSA, 10.10.10.5, 0x80000038 Router-LSA, 10.10.10.6, 0x80000005 Database } Description of 10.10.10.2 Acknowledges Database Description: Sequence = X+1 receipt of description 1 LSA Headers = { Router-LSA, 10.10.10.2, 0x80000005 } Database Description: Sequence = X+1 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 22

  44. Regular LSA Exchange 10.10.10.1 10.10.10.2 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 23

  45. Regular LSA Exchange 10.10.10.1 10.10.10.2 Link State Reequest packets, LSAs = { Router-LSA, 10.10.10.1, Router-LSA, 10.10.10.3, Router-LSA, 10.10.10.4, 10.10.10.2 explicitly Router-LSA, 10.10.10.5, requests each LSA Router-LSA, 10.10.10.6, from 10.10.10.1 } thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 23

  46. Regular LSA Exchange 10.10.10.1 10.10.10.2 Link State Reequest packets, LSAs = { Router-LSA, 10.10.10.1, Router-LSA, 10.10.10.3, Router-LSA, 10.10.10.4, 10.10.10.2 explicitly Router-LSA, 10.10.10.5, requests each LSA Router-LSA, 10.10.10.6, from 10.10.10.1 } 10.10.10.1 sends requested LSAs Link State Update Packet, LSAs = { Router-LSA, 10.10.10.1, 0x80000006, LSA... Router-LSA, 10.10.10.3, 0x80000007, LSA... Router-LSA, 10.10.10.4, 0x8000003a, LSA... Router-LSA, 10.10.10.5, 0x80000038, LSA... Router-LSA, 10.10.10.6, 0x80000005, LSA.... } thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 23

  47. Regular LSA Exchange 10.10.10.1 10.10.10.2 Link State Reequest packets, LSAs = { Router-LSA, 10.10.10.1, Router-LSA, 10.10.10.3, Router-LSA, 10.10.10.4, 10.10.10.2 explicitly Router-LSA, 10.10.10.5, requests each LSA Router-LSA, 10.10.10.6, from 10.10.10.1 } 10.10.10.1 sends requested LSAs Link State Update Packet, LSAs = { Router-LSA, 10.10.10.1, 0x80000006, LSA... Router-LSA, 10.10.10.3, 0x80000007, LSA... Router-LSA, 10.10.10.4, 0x8000003a, LSA... 10.10.10.2 has more Router-LSA, 10.10.10.5, 0x80000038, LSA... recent value for Router-LSA, 10.10.10.6, 0x80000005, LSA.... 10.10.1.6 and sends } it to 10.10.10.1 (with higher Link State Update Packet, sequence number) LSAs = { Router-LSA, 10.10.10.6, 0x80000006, LSA.... } thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 23

  48. Routing Data Distribution 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 24

  49. Routing Data Distribution 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 24

  50. Routing Data Distribution 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 24

  51. Routing Data Distribution 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 24

  52. Routing Data Distribution Update database 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 24

  53. Routing Data Distribution Update database 10.10.10.1 10.10.10.2 10.10.10.4 10.10.10.6 10.10.10.3 10.10.10.5 thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 24

  54. LSA Updates • Triggered by local topology or link cost changes • A received LSA that contains no new information is suppressed • Exception: very infrequent (every 30 min) flooding • Acknowledgement: • explicit ACK • implicit via reception of LSA Update thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 25

  55. Question • What is the role of the Database Description packets? thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 26

  56. OSPF Autonomous System • A region of the Internet administered by a single entity. • Examples of autonomous regions are: • X’s campus network • Frees backbone network • Routing is done differently within an autonomous system (intradomain routing) and between autonomous system (interdomain routing). thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 27

  57. Large OSPF nets • Large link-state table • Each router maintains a LSDB for all links • The LSDB requires the use of memory • Frequent SPF calculations • Topology changes; re-run Dijkstra • Flapping links • Large routing table • Solution: Divide the network into multiple areas thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 28

  58. Multi-Area OSPF • A flapping link will affect only an area • Dijkstra only when changes within that area • Complete topology only for that area ➡ Separate large network into smaller ➡ Hierarchical routing ➡ Area == Isolation of “problems” thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 29

  59. Area 0 / Area 2 Backbone Area Area 1 Ext. AS thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 30

  60. Area 0 / Area 2 Backbone Area Area 1 Internal Routers Ext. AS thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 30

  61. Area 0 / Area 2 Backbone Area Area 1 Internal Routers Backbone Routers Ext. AS thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 30

  62. Area 0 / Area Border Router Area 2 Backbone Area Area 1 Internal Routers Backbone Routers Ext. AS thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 30

  63. Area 0 / Area Border Router Area 2 Backbone Area Area 1 Internal Routers Backbone Routers Ext. AS Border Router AS thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 30

  64. Area 0 / Area Border Router Area 2 Backbone Area Area 1 Internal Routers Backbone Routers Ext. AS Border Router AS thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 30

  65. Internal Routers Backbone Routers Area Border Router AS Border Router thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 31

  66. Internal Routers Routers with all their interfaces within the same area Backbone Routers Routers with at least one interface connected to area 0 AS Border Router Routers that have at least one interface connected to an another autonomous system Area Border Router Routers with interfaces attached to multiple areas within the same autonomous system thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 32

  67. Internal Routers Backbone Routers Routers with at least one interface connected to area 0 AS Border Router Routers that have at least one interface connected to an another autonomous system Area Border Router Routers with interfaces attached to multiple areas within the same autonomous system thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 32

  68. Internal Routers Backbone Routers AS Border Router Routers that have at least one interface connected to an another autonomous system Area Border Router Routers with interfaces attached to multiple areas within the same autonomous system thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 32

  69. Internal Routers Backbone Routers AS Border Router Area Border Router Routers with interfaces attached to multiple areas within the same autonomous system thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 32

  70. Internal Routers Backbone Routers AS Border Router Area Border Router thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 32

  71. Internal Routers Backbone Routers AS Border Router Area Border Router thomas@thomasclausen.org http://www.thomasclausen.org mark@townsley.net http://www.townsley.net/ 33

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend

Routing In Ad Hoc Networks 1. Introduction to Ad-hoc networks 2. Routing in Ad-hoc networks 3.

Routing In Ad Hoc Networks 1. Introduction to Ad-hoc networks 2. Routing in Ad-hoc networks 3.

Routing In Ad Hoc Networks 1. Introduction to Ad-hoc networks 2. Routing in Ad-hoc networks 3. Proactive routing protocols DSDV 4. Reactive routing protocols DSR, AODV 5. Non-uniform routing protocols ZRP, CEDAR 6. Other

392 views • 22 slides
End-to-End Protocols Guevara Noubir Textbook: Computer Networks: A

End-to-End Protocols Guevara Noubir Textbook: Computer Networks: A

End-to-End Protocols Guevara Noubir Textbook: Computer Networks: A Systems Approach, L. Peterson, B. Davie, Morgan Kaufmann Chapter 5. Fundamentals of Computer Networks End-to-End Protocols 1 Lecture Outline

516 views • 47 slides
Securing Home Networks Securing Home Networks protocols protocols A SWN04 A SWN04 K.

Securing Home Networks Securing Home Networks protocols protocols A SWN04 A SWN04 K.

Securing Home Networks Securing Home Networks protocols protocols A SWN04 A SWN04 K. MASMOUDI, K. MASMOUDI, H. AFIFI H. AFIFI Boston, 08/2004 6 th PCRD Integrated Project Goal : provide secure communication

450 views • 22 slides
Next Generation Networks Next Generation Networks QoS Control Architectures and QoS Control

Next Generation Networks Next Generation Networks QoS Control Architectures and QoS Control

I nternational Telecom m unication Union ITU-T Next Generation Networks Next Generation Networks QoS Control Architectures and QoS Control Architectures and Protocols Protocols Keith Mainwaring Technical Leader, Cisco S ystems I TU-T W

662 views • 19 slides
4 Application Layer Protocols Device Management Protocols Application layer protocols offering

4 Application Layer Protocols Device Management Protocols Application layer protocols offering

EPFL, Spring 2017 4 Application Layer Protocols Device Management Protocols Application layer protocols offering remote services for large networks of devices: - Monitoring (health of devices and network, get current state) - Management

1.31k views • 93 slides
Wireless Networks and Protocols MAP-Tele Manuel P. Ricardo Faculdade de Engenharia da

Wireless Networks and Protocols MAP-Tele Manuel P. Ricardo Faculdade de Engenharia da

WNP-MPR-Fundaments 1 Wireless Networks and Protocols MAP-Tele Manuel P. Ricardo Faculdade de Engenharia da Universidade do Porto WNP-MPR-Fundaments 2 Topics Scheduled for Today Introduction to Wireless Networks and Protocols

1.16k views • 97 slides
When Users Interfere with Protocols Prospect Theory in Wireless Networks WINLAB Narayan B.

When Users Interfere with Protocols Prospect Theory in Wireless Networks WINLAB Narayan B.

When Users Interfere with Protocols Prospect Theory in Wireless Networks WINLAB Narayan B. Mandayam (joint work with Tianming Li) Motivation: Engineered System Design Current radio technologies and associated communication protocols are

665 views • 28 slides
Wireless Networks: Network Protocols/Mobile IP Mo$va$on

Wireless Networks: Network Protocols/Mobile IP Mo$va$on

Wireless Networks: Network Protocols/Mobile IP Mo$va$on Problems Data transfer DHCP Encapsula$on Security IPv6 Adapted from J. Schiller,

441 views • 29 slides
Direct Link Networks: Multiaccess Protocols (2.7) CS/ECpE 5516: Computer Networks Originally by

Direct Link Networks: Multiaccess Protocols (2.7) CS/ECpE 5516: Computer Networks Originally by

Direct Link Networks: Multiaccess Protocols (2.7) CS/ECpE 5516: Computer Networks Originally by Scott F. Midkiff (ECpE) Modified by Marc Abrams (CS) Virginia Tech courses.cs.vt.edu/~cs5516 Lecture Topics I Multiaccess control I IEEE 802.5

725 views • 39 slides
Chapter 8 Communication Networks and Services 1. IPv6 2. Internet Routing Protocols: OSPF,

Chapter 8 Communication Networks and Services 1. IPv6 2. Internet Routing Protocols: OSPF,

Chapter 8 Communication Networks and Services 1. IPv6 2. Internet Routing Protocols: OSPF, RIP, BGP 3. Other protocols: DHCP, NAT, and Mobile IP Chapter 8 Communication Networks and Services IPv6 Fall 2012 Prof. Chung-Horng Lung 2 IPv6

552 views • 52 slides
Ad hoc and Sensor Networks Chapter 11: Routing protocols Holger Karl Computer Networks Group

Ad hoc and Sensor Networks Chapter 11: Routing protocols Holger Karl Computer Networks Group

Ad hoc and Sensor Networks Chapter 11: Routing protocols Holger Karl Computer Networks Group Universitt Paderborn Goals of this chapter In any network of diameter > 1, the routing & forwarding problem appears We will discuss

586 views • 47 slides
Principles and Protocols for Power Control in Wireless Ad Hoc Networks Vikas Kawadia and P. R.

Principles and Protocols for Power Control in Wireless Ad Hoc Networks Vikas Kawadia and P. R.

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS: SPECIAL ISSUES ON WIRELESS AD HOC NETWORKS 1 Principles and Protocols for Power Control in Wireless Ad Hoc Networks Vikas Kawadia and P. R. Kumar Department of Electrical and Computer

313 views • 13 slides
Wireless Ad Hoc & Sensor Networks Wireless Ad Hoc & Sensor Networks Multiple Access

Wireless Ad Hoc & Sensor Networks Wireless Ad Hoc & Sensor Networks Multiple Access

Outline Wireless Ad Hoc & Sensor Networks Wireless Ad Hoc & Sensor Networks Multiple Access Technique Medium Access Control Application Designing Issues of MAC protocols Classification of MAC protocols Classification of

306 views • 14 slides
Synthesis of software-based protocols for dynamically reconfigurable networks Ufuk Topcu (Univ of

Synthesis of software-based protocols for dynamically reconfigurable networks Ufuk Topcu (Univ of

Synthesis of software-based protocols for dynamically reconfigurable networks Ufuk Topcu (Univ of Pennsylvania) www.seas.upenn.edu/~UTopcu Outline: Reconfiguration in electric power networks on aircraft An academic testbed Newer

460 views • 29 slides
Chapter 8 Communication Networks and Services 1. IPv6 2. Internet Routing Protocols: OSPF,

Chapter 8 Communication Networks and Services 1. IPv6 2. Internet Routing Protocols: OSPF,

Chapter 8 Communication Networks and Services 1. IPv6 2. Internet Routing Protocols: OSPF, RIP, BGP 3. Other protocols: DHCP, NAT, and Mobile IP Chapter 8 Communication Networks and Services IPv6 SYSC5201 2 IPv6 Longer address

898 views • 55 slides
CompSci 514: Computer Networks Lecture 14 Datacenter Transport protocols II Xiaowei Yang

CompSci 514: Computer Networks Lecture 14 Datacenter Transport protocols II Xiaowei Yang

CompSci 514: Computer Networks Lecture 14 Datacenter Transport protocols II Xiaowei Yang Roadmap Clos topology Datacenter TCP Re-architecting datacenter networks and stacks for low latency and high performance Best Paper award,

437 views • 41 slides
Testes caixa preta - 1 Abordagens combinatrias Criao: Abr/2001 Reformulao: Mar/2013

Testes caixa preta - 1 Abordagens combinatrias Criao: Abr/2001 Reformulao: Mar/2013

Testes caixa preta - 1 Abordagens combinatrias Criao: Abr/2001 Reformulao: Mar/2013 Referncias M. Pezz, M. Young. Teste e Anlise de Software . Bookman Companhia Editora, 2008, cap. 10 e 11. P. Ammann, J. Offutt. Introduction to

899 views • 59 slides
for Cooperative Agents Shlomo Zilberstein Shlomo Zilberstein School of Computer Science School of

for Cooperative Agents Shlomo Zilberstein Shlomo Zilberstein School of Computer Science School of

Multiagent Multiagent Planning Planning Planning under Uncertainty for Cooperative Agents Shlomo Zilberstein Shlomo Zilberstein School of Computer Science School of Computer Science ! Challenge : How to achieve intelligent coordination of a

473 views • 30 slides
A Flow Control Strategy for Connectionless Traffic over an ATM Network Lorne G. Mason

A Flow Control Strategy for Connectionless Traffic over an ATM Network Lorne G. Mason

0 A Flow Control Strategy for Connectionless Traffic over an ATM Network Lorne G. Mason INRS-Telecommunications University of Quebec, Nuns Island, Quebec H3E 1H6 e-mail: lgmason@telusplanet.net Felisa J. V azquez-Abad Department of Computer

417 views • 13 slides
CHES Tutorial Cryptographic hardware: how to make it cool, fast and secure Junfeng Fan KULeuven,

CHES Tutorial Cryptographic hardware: how to make it cool, fast and secure Junfeng Fan KULeuven,

9/9/2012 CHES Tutorial Cryptographic hardware: how to make it cool, fast and secure Junfeng Fan KULeuven, ESAT/SCD-COSIC CHES 2012 Crypto hardware 9/9/2012 CHES Tutorial: Crypto hardware design 3 1 9/9/2012 Smart card SoC (NXP P60C080)

826 views • 54 slides
9/22/10 VISUAL FEATURES OF KIM Kimberlitic Indicator Minerals Maja Kiridzija Knowing the

9/22/10 VISUAL FEATURES OF KIM Kimberlitic Indicator Minerals Maja Kiridzija Knowing the

9/22/10 VISUAL FEATURES OF KIM Kimberlitic Indicator Minerals Maja Kiridzija Knowing the micro world leads to the macro discovery OBJECTIVE At the end of todays activities you will be able to identify and separate KIM grains from

473 views • 30 slides
Morphomic properties and the interface of syntacticosemantic content with morphological form

Morphomic properties and the interface of syntacticosemantic content with morphological form

Morphomic properties and the interface of syntacticosemantic content with morphological form Gregory Stump University of Kentucky University of Leipzig, July 8, 2015 1 Morphosyntactic grammatical properties to which properties: morphology

1.97k views • 180 slides
Effective Metadata Systems for Archives EAD and Unified Collection Management Systems Gregory

Effective Metadata Systems for Archives EAD and Unified Collection Management Systems Gregory

Effective Metadata Systems for Archives EAD and Unified Collection Management Systems Gregory Wiedeman University Archivist University at Albany, SUNY Archival Metadata Systems Paper Finding Aids HTML Finding Aids EAD records

326 views • 19 slides
Near-surface regions of chalcopyrite (CuFeS 2 ) studied using XPS, HAXPES, XANES and DFT Yuri

Near-surface regions of chalcopyrite (CuFeS 2 ) studied using XPS, HAXPES, XANES and DFT Yuri

2016 International Conference Synchrotron and Free electron laser Radiation: generation and application, Novosibirsk Near-surface regions of chalcopyrite (CuFeS 2 ) studied using XPS, HAXPES, XANES and DFT Yuri Mikhlin, Alexander

237 views • 20 slides

More recommend