1. DNS and IP Scalability Communication Systems Design 2002

2. 2 DNS and IP Scalability  Members  Daniel Hedberg  Liyi Meng  Patrick Brosset  Thomas Wetterberg  YanHong Xu  Principal  B.Svante Eriksson, SCINT  Coach  Fredrik Lilieblad

3. 3 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A

4. 4 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A  Scalability?  Limitation of Scope

5. 5 What is Scalability?  Ease of handling changes in volume  Ease of supporting new services

6. 6 In the beginning...  DNS security requirements  Quality of Service for VoIP  The growing in routing tables  The load on Internet Exchanges  The lack of IP adresses ...

7. 7 Limitation of Scope  DNS and IP Scalability  DNS  Transition - from IPv4 to IPv6

8. 8 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A

9. 9 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A  IPv6  Security  Root Servers  Emerging Services

10. 10 DNS  Domain Name System  Distributed Database

11. 11 DNS  2 transactions  Query – Response->UDP  Zone Transfers->TCP Size Limit – 512 bytes Connection oriented – large overhead

12. 12 DNS and IPv6  Addresses 128 bits  2 DNS records  AAAA  A6 35N56 – N64 010RegistryIDProviderIDSubscriberIDHost 010 3 RegistryID 5 ProviderID N SubscriberID 56 – N Host 64 Fragmented IPv6 address

13. 13 DNS and IPv6 Scalability  AAAA and A6->Larger packets  A6 ->More queries

14. 14 DNS and Security  DNSSEC  Protect against:  Manipulation of data  Masquerading of data origin  Protects by:  Signing each response  ”Chain of trust”

15. 15 DNS and Security Scalability  DNSSEC  Signed records->Larger packets  Check zone keys->More Queries

16. 16 DNS services  DNS available  Globally  All the time  Ideal for storage  Public encryption keys  Certificates

17. 17 DNS services ENUM – ”Electronic numbers”  Telephone numbers –> URIs  Phone / fax / mobile  IP-telephony / SIP  E-mail / SMS / Voice mail server  Public encryption keys  ENUM using DNS stores information  User decides priority of services  Processing in the host

18. 18 DNS services Scalability  New services->More queries  Medium sized packets  Risk of packet growth

19. 19 Root servers  Critical for all DNS operation  Need for One, Unique root

20. 20 Root servers  Limited number - 13  Zone transfer by UDP  Uneven distribution

21. 21 Root server Operation  Load –> 5 000-8 000 queries/second  Can handle 40 000 - 50 000 q/s  2/3 can go down without loosing service  ”Normal” computers

22. 22 Root server Scalability  Traffic volume increases  IPv6 addresses

23. 23 DNS Conclusions  Volume will increase  Split a zone -> share the load ”DNS is the most scalable database ever designed” – Johan Ihrén, Autonomica  Packet size will increase  DNSSEC  IPv6  IPv6 + DNSSEC  New services + DNSSEC  UDP packets to small -> TCP connections

24. 24 DNS Conclusions (cont.)  Solution already designed – IPv6  UDP packet size 1280 bytes  Will take time to implement  IPv6 queries will be routed over IPv4

25. 25 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A

26. 26 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A  Overview  Mechanisms  Conclusions

27. 27 Why do we need IP Transition?

28. 28 IP transition

29. 29 IP Transition strategies  Company Level  IPv6 over IPv4 tunnels  Translation mechanisms  ISP / Backbone  IPv6 over dedicated datalink  IPv6 over MPLS backbone  Dual stack backbones

30. 30 What did we do?  Dual Stack  6to4  ISATAP  NAT-PT  Teredo  Because  Focus on finding solutions for company users  Not all implementations are available  Time limitation

31. 31 About the test The test measure:  Throughput – FTP, HTTP  Path characteristics (Delay, bottleneck, queuing) – pchar  Packet loss – MGEN All these results are compared between IPv4, transition and IPv6

32. 32 Transition mechanism  Dual Stack  6to4  ISATAP  NAT-PT  Teredo

33. 33 Dual Stack How it works

34. 34 Dual Stack Features & Limitations  IPv4 Requirements  1 IPv4 address per host  IPv4 connectivity remains  Scale-up of hardware and software  Implementation all at once  More processing and memory in the router to manage both IPv4 & IPv6  DNS requirements  AAAA records.

35. 35 Dual Stack Features & Limitations  Support of services  end-to-end  real-time  Mobile IP  Multicasting  Open Acess Network  Flow labels  Anycast  Connectivity/Reliability  Same connectivity as a pure IPv6 network

36. 36 Dual Stack Conclusion  Benefits  Important technology for other mechanisms  Have every support that IPv6 has  Limitations  Double-work and management

37. 37 Transition mechanism  Dual Stack  6to4  ISATAP  NAT-PT  Teredo

38. 38 6to4 How it works

39. 39 6to4 Features & Limitations  IPv4 Requirements  1 IPv4 address per site  Scale-up of hardware and software  Implementation all at once  further scale-up very easy  DNS requirements  IPv6 DNS  6to4 tunnel won’t work through NAT

40. 40 6to4 Features & Limitations  Support of services  end-to-end  real-time  Mobile IP: not supported (IPv4).  Flow labels not supported.  Connectivity/Reliability  Effect of a router going down  Performances  - 5%

41. 41 6to4 Our Testing network

42. 42 6to4 Test Result Throughput

43. 43 6to4 Test Result Path characteristics

44. 44 6to4 Test Result The Packet Loss

45. 45 6to4 Conclusion  Benefits  Easy to startup  No management overhead in the future  Limitation  Tunneling can not go through NAT box  Maybe loss connectivity when tunneling over IPv4 island  User  Suitable for companies that want to migration to IPv6 all at once.

46. 46 Transition mechanism  Dual Stack  6to4  ISATAP  NAT-PT  Teredo

47. 47 ISATAP How it works  Intra-Site  Communication between two IPv6 nodes over an IPv4 network  Host automatically creates a tunnel to an ISATAP router

48. 48 ISATAP How it works

49. 49 ISATAP Features & Limitations  IPv4 Requirements  1 IPv4 address per ISATAP host  IPv4 connectivity remains  Scale-up of hardware and software  Implementation step-by-step  further scale-up easy  DNS requirements  Well-known service ISATAP (for hosts)  AAAA records.  Won't work through a NAT

50. 50 ISATAP Features & Limitations  Support of services  end-to-end  real-time  private IPv4 addresses  Mobile IP: not supported (IPv4)  Flow labels not supported  Connectivity/Reliability  ISATAP router is the critical point  Performances  - 3%

51. 51 ISATAP Our Testing network

52. 52 ISATAP Test Result Throughput

53. 53 ISATAP Test Result Path characteristics

54. 54 ISATAP Test Result Packet Loss

55. 55 ISATAP Conclusion  Benefits  Suits very well for companies deploying IPv6 step-by-step.  Setup easy.  Further scale-up easy.  Limitation  Still relies on IPv4 infrastructure.  User  Big company networks

56. 56 Transition mechanism  Dual Stack  6to4  ISATAP  NAT-PT  Teredo

57. 57 NAT-PT How it works Network Address Translation- Protocol Translation Works for communication between IPv6 only host and IPv4 only host

58. 58 NAT-PT How it works FEDC:BA98::7654:3210 IPv6 server IPV4 only network IPv6 native network NAT-PT IPv6 host IPv4 server IPv4 host 132.146.243.30 (DNS-ALG) SA=FEDC:BA98::7654:3210 DA=PREFIX::132.146.243.30 SA=120.130.26.10 DA=132.146.243.30

59. 59 NAT-PT Features & Limitations IPv4 requirements At least one global address Scale-up Configuration all at once Further scale-up easy DNS requirements ALG

60. 60 NAT-PT Features & Limitations Connectivity NAT box easy to overload NAT box = critical point Support of services Breaks end-to-end principle

61. 61 NAT-PT Conclusion Benefits: Enables interoperation between pure IPv4 and pure IPv6 Limitations: End-to-end connectivity Security Users: Suitable for a new IPv6 company A temporary patch before entire migration

62. 62 Transition mechanism  Dual Stack  6to4  ISATAP  NAT-PT  Teredo

63. 63 Teredo How it works  Tunneling over UDPv4 through NAT  Teredo server  Teredo relay connects to IPv6

64. 64 Teredo How it works

65. 65 Teredo Features & Limitations  IPv4 Requirements  All hosts behind the NAT share on a pool of addresses  Scale-up of hardware and software  Implementation step-by-step  DNS requirements  Dynamic updates on DNS  AAAA records

66. 66 Teredo Features & Limitations  Support of services  real-time (might be possible)  private IPv4 addresses  Mobile IP: not supported  Flow labels not supported  Connectivity/Reliability  If the Teredo server, relay or NAT box goes down, connections break down...

67. 67 Teredo Conclusion  Benefit  enables tunnel through a NAT box  Limitation  3 critical points  User  Big company networks that have a NAT implemented and want IPv6 connectivity

68. 68 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A  Overview  Mechanisms  Conclusions

69. 69 IP transition Conclusions Facts  Degradation of throughput not significant  Packet loss also acceptable in most cases.  IPv6 “strange” delay  Early-state applications  Tunnel links are a bottleneck  extra processing  Our conclusion

70. 70 IP transition Conclusions Recommendations  Smaller case  Small network  Able to migrate all at once  Pure IPv6 + 6to4 + NAT- PT  Further scale-up easy

71. 71 IP transition Conclusions Recommendations  larger case  Large company network  Cannot configure all at once  ISATAP  Setup easy  Private addresses supported  Further scale-up easy

72. 72 IP transition Conclusions Lab sessions experience  Lot’s of configuration problems  Test more difficult  6to4 standardized  Draft state OS’s and applications  But most of the technics are workable  Now it’s time to migrate!

73. 73 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A

74. 74 Video – Start projektor

75. 75 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A

76. 76 Summary DNS  Volume will increase  No problem  Packet size will increase  Problem!  UDP packets to small -> TCP connections  Solution excists -> IPv6

77. 77 Summary IP Transition  Mechanims work well  Choose the one that fits your needs

78. 78 Overview  Introduction  DNS  IP Transition  Video  Summary  Q & A