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AIMS'99 Workshop AIMS'99 Workshop
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AIMS'99 Workshop AIMS'99 Workshop

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  • 1. P805: Internet Roaming
    • Giuseppe Sisto - Telecom Italia / CSELT
    • [email_address]
    • Project participants:
    • Deutsche Telecom
    • Finnet Group
    • France Telecom
    • MATAV
    • Telecom Italia
  • 2.
    • Scope
    • Objectives
    • Technical approach
    • P805 results
    • P914 expected results
  • 3. The Scope (from P717)
    • Multiple ISPs in each country
    • Problem similar to GSM roaming
    • Same model for roaming solution
    • Based on bilateral agreements between parties
    • No central clearing point
    • Distributed solution: Scaleable and robust
  • 4. Roaming Service Reference Model Home ISP’s Roaming User Traditional, Centralized Solution: 3rd Party Clearing Point P805 Solution: Direct A-A Interface The Internet Remote ISP Home ISP Authentication Server for Remote ISP NAS: Network Access Service Authentication Server for Home ISP
  • 5.
    • Terminal-network interface:
      • should work for PSTN and ISDN
      • should work for most common devices and configurations
    • Network-network interface (A-A protocol)
      • should allow transport of all necessary parameters
      • should be secure (encryption, mutual validation)
      • should run over IP
    • Compatible with existing third party solutions
    The Requirements
  • 6. The Possible Solutions
    • The solutions examined
    • HTTP based
    • RADIUS Based
    • RADIUS/LDAP Integration
  • 7. HTTP-based Solution
    • SIR: Secure Internet Roaming specification (i-Pass consortium)
    • good security level (use of encryption and digital certificates)
    • based on a “centralized” model (MSS= Message Switching Server): out of our scope
    Home ISP (H-ISP) NAS RSAP Remote ISP (R-ISP) H-ISP’s Roaming User MSS VNAS Authorizing entity Encrypted communication with HTTP on SSL PPP with CHAP
  • 8. RADIUS-based Solution
    • No end-to-end security in case of untrusted intermediate proxies
    • Protocol not extensible: need for a new protocol
    Home ISP (H-ISP) NAS Remote ISP (R-ISP) AAA-Server (RADIUS) H-ISP’s Roaming User AAA-Server (RADIUS) Intermediate ISP (I-ISP) AAA-Server (RADIUS) PPP with CHAP
    • Framework for any service which requires AAA/Policy support
    • flexible/ extensible
    • Wide range of security solutions (including X.509 certificates)
    • Roaming scenario not yet available in ‘98
    • Only one “experimental” implementation from Merit
    • Not yet officially recognized by IETF
    RADIUS Protocol DIAMETER Protocol Home ISP (H-ISP) NAS H-ISP’s Roaming User DIAMETER (proxy) Server PPP with CHAP DIAMETER (proxy) Server Remote ISP (R-ISP)
  • 10. A Directory Enabled Solution
    • Directory Enabled Networks: a single common directory to support all applications, services and infrastructure
    • LDAP v. 3 (Lightweight Directory Access Protocol): IETF standard for Internet Directories (RFC2251)
    • Client/Server Model, Distributed Service, Security Framework (Access Control / TLS / SASL)
    Directory Service E-mail Network Operating System Other Applications
  • 11. LDAP-based roaming model H-ISP Roaming User RADIUS Server LDAP Client R-ISP LDAP Server 2. Referral to H-ISP LDAP server 1. LDAP Inquiry AAA Server NAS [email_address] Password Remote ISP (R-ISP) H-ISP LDAP Server 3. Inquiry to H-ISP LDAP Server Home ISP (H-ISP) RADIUS
  • 12. Directory information modeling (referral entry) Uid=ISPnAuthorisedUser ISP1 O = ISP1 (i.e. o=TIN.IT) Uid=ISP1User 1 Uid=ISP1User 2 Uid=ISP1User N O=ISP2 (referral entry) O=ISP n “ “ ... … . ... O=ISP1AdminUsers Pointers to other ISPs’ LDAP servers
  • 13. The Pilot
  • 14. Implementation description
    • Merit AAA Server (basic version)
    • Netscape Directory Server
    • Project Development of RADIUS/LDAP gateway
    • Set up of a Certification Authority to issue X.509 certificates for the use of SSL (sn=SIRTE CA,o=CSELT, c=IT)
  • 15. The Trials
    • Functionality tests
      • whole chain from roaming end-user to home ISP’s directory server
    • Performance tests
      • local access vs. remote access of a user
      • secure connections vs. non secure connections between LDAP servers
      • influence of DB size
    • “ Near Operational” tests
      • All participants simultaneously authenticating themselves both locally and remotely over a period of time
  • 16. Results from the Trials
    • Functionality tests: the model works!
    • Performance tests
      • Local access:
        • non-secure connections: delay of few tenths of a second
        • secure connections: delay of ~ 1/3 vs. non secure
        • no influence of DB size
      • Remote access
        • network delay of few seconds: the delay introduced by use of SSL not relevant.
    • “ Near Operational” tests: influenced by network conditions
  • 17. Recommendations from the Pilot
    • ISPs:
    • before signing contracts for centralised solutions with third party providers, first identify the participation costs to the consortia;
    • do not sign “exclusive” contracts for centralised solutions with third party providers; keep the possibility to offer at the same time a de-centralised solution!
    • keep under observation the research activity, which may provide important innovations the near future,
  • 18. P914: Study and Trials for Internet Roaming in Europe Two new participants: Portugal Telecom and Telefonica España
    • Enhancements to the Roaming Solution: management aspects, accounting mechanisms, security, directory phonebook
    • Client Interface for Roaming users
    • Support DIAMETER work; development and trial of a DIAMETER-based roaming solution (EURESCOM now member of Merit AAA consortium, members active participants to IETF Roamops and AAA Groups).
    Scope & Activities