TTM4130 Service Intelligence and mobility Spring 2008

1. TTM4130 Service Intelligence and mobilitySpring 2008 Chapter 10 Addresses, identities and names Steinar Andresen

2. Name hierarchy in Internet * * New additions, 20-feb-2006: .cat, .jobs, .mobile and .travel

3. Where ISO 3166 and ICANN/IANA differ • ISO: GB • ICANN: • .ac  –  Ascension Island • .gg  –  Guernsey • .im  –  Isle of Man • .je  –  Jersey • .uk  –  United Kingdom (England, Scotland and Whales). • ISO: TL (East Timor) ICANN: No entry

4. How to find the address? • Address Resolver (at the user) connects the application program with DNSF and finds the address either • in local cache or • By asking the nearest local nearest name server. • Local Name Server • Finds the address in cache, and answers or • Asks another name server to obtain the answer (proxy - this working scheme is termed recursive) or • Reply back with an address (”a link”) to a name server that ”knows better” (this working scheme is termed iterative)

5. Why is not DNScentralised? Because this would give: • A vulnerable system( with a ”single point of failure”) • To great traffic volume on a single server. • A remote centralised data base (which may result in long delays and vulnerability to network faults). • Problems with up dates • A solution that do not scale.

6. The local name server • Is “the first stop” when trying to retrieve the address. • A local name server usually operates in a recursive (proxy) mode, i.e. it acts on behalf of the client in order to find the complete address. Root name servers • Are multiplied • In order not to put too much load on a single server and • To obtain a more resilient system. • The root name servers to day operates today in an iterative way (”re-direct”) • There is 13 such servers.

7. Iterative DNS address retrieval The operation is iterative as seen from the from the local name server

8. Root servers 2005

9. 13 root servers in DNS per 20. Feb. 2006 Letter Old name Operator Location A ns.internic.net VeriSign Dulles, Virginia, USA B ns1.isi.edu ISI Marina Del Rey, California, USA C c.psi.net Cogent distributed using anycast D terp.umd.edu University of Maryland College Park, Maryland, USA E ns.nasa.gov NASA Mountain View, California, USA F ns.isc.org ISC distributed using anycast G ns.nic.ddn.mil U.S. DoD NIC Columbus, Ohio, USA H aos.arl.army.mil U.S. Army Research Lab Aberdeen Proving Ground, Maryland, USA I nic.nordu.net Autonomica distributed using anycast J VeriSign distributed using anycast K RIPE NCC distributed using anycast L ICANN Los Angeles, California, USA M WIDE Project Tokyo, Japan

10. Root servers 2007

11. Root servers 2007 (continued)

12. The functions of a Name Server • All name servers (except the root name servers) are able to find the address in • Own database • In a local copy of the database of another name server or • In a local ”cache” (results from request made earlier) • An authoritative name server for a given host • Stores the name and the IP address of the host • Can realise address resolution for this host name. (All hosts must have at least on authoritative name server

13. D(ynamic)DNS • Methodology discussed in • RFC 2136 Dynamic Updates in the Domain System and • RFC 3007 Secure Domain Name System (DNS) Dynamic Update. Can be utilised to in order to realise dynamic up dates of mapping between names (that usually should be kept) and current valid IP addresses. Some enterprises have specialized themselves in a business aimed at providing DDN to domain name owners that moves a lot , see e.g.: http://www.google.com/Top/Computers/Software/Internet/Servers/Address_Management/Dynamic_DNS_Services/

14. Caching The mapping between a name and address can be retained or ”cached” at the server. Recommended times (measured in seconds) for activities at top domain servers are:o 86400 Refreshing entries - every 24 hour o 7200 Make a new trial every 2. hour o 2592000 Delete ”on date” 30 days o 345600 Least time to live(TTL) 4 days

15. Address system of IP version 6 • Unicast • Anycast • Multicast (includes “broadcast) • Address is written in a form made up of 8 groups, each group consists of 4 digits from a hexadecimal character set. Each group encodes 16 bit (or 2 octets). Colons ( ”:”) is used as a delimiter between groups. Samples: • FEDC:BAC98:7654:3210:FEDC:BHAC98:7636:3219 and • 1080:0:0:0:8:800:200C:417A

16. Prefix specification In order to realise an explicit length specification for the prefixes (encompass all sub net identities in the address) one can write ”/prefix length” after the address, e.g.: 1080::8:800:200C:417A/64 specifying a prefix 1080:0:0:0 and an interface identity of 8:800:200C:417A.

17. Address types

18. Global Unicast(the “common” form) usually n + m = 64

19. Addresses with a confined area of validity (scope)

20. Multicast addresses

21. Solicited-node multicast - link-local (Etterspurt nodes multikastadresse) This is an address of the format: FF02:0:0:0:0:1:FFXX:XXXX • XX:XXXX corresponds to the last 24 bit of the unicast (or anycast) address of the node. • This address form is used when a node need to “attach” to one or more multicast groups. Groups with different prefixes will create only one solicited-node multicast group per interface. This is a ”smart form” of addressing that is utilised under the neighbour discovery process.

22. Addresses that must be recognised (by a normal host that is not a router) • Assigned link local addresses (for all interfaces) • Any unicast or anycast address configured for the interfaces of the node (manually or automatically) • The Loopback address, • ”All local-nodes” multicast addresses as defined earlier • The corresponding ” Solicited-node multicast addresses” that may be created on the basis of any uni- or anycast address assigned to the node. • Multicast addresses for all other groups where the node participates as a member.

23. Additional addresses that must be recognised by a router • Subnet-router anycast addresses for all interfaces of the node where it acts as a router. • All other anycast addresses that has been configured for the router. • ”All-link local-routers” multicast addresses, as defined earlier.

24. Figure 10.10bis. Correction

25. MAC (IEEE) Org ID=24 bit “Serial number” =24 bit EUI (Extended Unique Identifier)-64 bits with an encapsulated 48 bits MAC value Org ID=24 bit FFFF “Serial number” =24 bit IPv6 address (formed by stateless autoconfiguration) Prefix and subnet field =64 bit EUI-64 with encapsulated MAC addr. Ref: http://standards.ieee.org/regauth/oui/tutorials/EUI64.html

26. Telephone Numbers E.164Sample number structure

27. Hierarchical number-structure

28. International “Freephone” number

29. IMSI

30. IMSI different interpretations (meaning essentially the same) • GSM International Mobile Subscriber Identity • IMS Subscriber Identifier • International Mobile Subscriber Identity • International Mobile Station Identifier + one that is different • Inter MAN (Metropolian Area Network) Subscriber Id.

31. The relation between different UMTS id-s and numbers • IMSI International Mobile Subscriber Identity • TMSI Temporary Mobile Subscriber Identity • TLLI Temporary Logical Link Identity • MSIDN Mobile Station International PSTN/ISDN Number • MSRN Mobile Station Roaming Number • MSIDN Mobile Station International Data Number -> IP address? • “Handover Number” • IMEI(SV) International Mobile Equipment Identifier (and Software version) • 8 digit Type Allocation Code + 6 digit Serial Number + 1digit reserved or 2 digits (giving IMEISV) referring to the software version

32. Location area (for circuit switched services)

33. Global Cell- Id (structure)

34. Name- and address concepts

35. The relation between private and public User ID in IM CN (IMS) User Id. specified in NAI (RFC2486) format: <user name>@<fully qualified domain name> Address on the form: sip: <user name>@< fully qualified domain name >