PANA in DSL networks draft-morand-pana-panaoverdsl-01.txt Lionel Morand France Telecom Alper Yegin Samsung Yoshihiro Ohba Toshiba John Kaippallimalil Huawei IETF-71, Philadelphia

Draft History IETF 66: IETF 67: IETF 67 and IETF 71: IETF 71: PANA use case for DSL removed from PANA Framework IETF 67: First presentation of the "PANA over DSL" draft (v00) IETF 67 and IETF 71: Draft frozen during finalization of PANA protocol DSL Liaison on access authentication requirements IETF 71: Update version of the "PANA over DSL" draft (v01) Based on final version of the PANA base protocol and comments received and outputs of DSLF liaison discussions

Context Evolution of DSL architecture in two steps: Moving from ATM-based aggregation to Gigabit Ethernet Moving from PPP-based environment to IP-based model "IP Sessions" model ongoing work in DSL Forum Basically, an IP session represents the subscriber IP traffic associated with an IP address Need for a subscriber access authentication mechanism DSL Forum working around DHCP evolution for supporting EAP DSL Liaison discussion during IETF70 in the Internet Area meeting session PANA should also be considered a natural candidate Fulfill DSL Forum security requirements provided in the Liaison

Summary Provides guidelines for PANA deployment over DSL access networks Focus on DSL networks migrating from: a traditional PPP access model Where PPP is used to carry authentication parameters (PAP/CHAP or EAP methods) to a pure IP-based access environment No built-in explicit per-subscriber access authentication Use of DHCP option 82 for implicit line-based authentication PANA provides such a mechanism in this environment

From v00 to v01 Alignment with PANA final specification Clarification on the possible PAA-EP interface Removal of reference to SNMP or ANCP Description of DHCP snooping/triggering mechanism Reorganization of the draft New section on the use of the MAC address as authorized device ID Added section on specific implementation example With the use of Link-local IPv4 address More details in message flow descriptions

PAA/EP Location ISP DSLAM BRAS ISP DSLAM BRAS PAA/EP DSL Modem/RG API or DHCP Snooping EP PAA BRAS ISP DSL Modem/RG DSLAM

PaC Location ISP DSLAM Bridge BRAS ISP DSLAM NAT/Router BRAS ISP DSLAM PAA/EP BRAS ISP DSL Modem/RG DSLAM PaC Bridge 1/ Bridged Mode in IPv4/IPv6 PAA/EP BRAS PaC ISP DSL Modem/RG DSLAM NAT/Router 2a/ Routed Mode in IPv4 PaC PAA/EP BRAS PaC ISP DSL Modem/RG DSLAM PaC Router 2b/ Routed Mode in IPv6

Use of PRPA/POPA Mainly useful in IPv4 context to prevent waste of scarce IP resources In IPv4 context, PRPA may be: Link-local IP address Private IP address Temporary allocated IP address with short-lease and/or limited use After a successful authentication, POPA is configured using DHCP

RADIUS/Diameter Authentication 6. IP Session/data traffic Generic Message Flows DSL Model/RG or host (PaC) DSLAM (EP) BRAS (PAA) AAA Server 1. PRPA Configuration 2. PAA Discovery 3. PANA Authentication RADIUS/Diameter Authentication 4. POPA Configuration* 5. EP filter setup 6. IP Session/data traffic *Only needed if the IP address needs to be reallocated

Specific example Deployment scenario in which: DSL Network configuration with: PaC in the DSL modem/RG BRAS hosting PAA, DHCP Server/Relay, and AAA client DSLAM acting as EP Link-local IPv4 address as PRPA DHCP-based PAA discovery EAP-MD5 Authentication method POPA configured using DHCPv4 EP is triggered by DHCPACK whose 'yiaddr' field is filled

Specific Message flows DSL Model/RG or host (PaC) DSLAM (EP) BRAS (PAA) EP Filter allowing only DHCP and PANA AAA Server No IP Address Allocation 1. Link local PRPA Configuration 2. DHCP Inform *(req PAA option) 3. DHCP Ack (PAA option) 4. PANA client initiation Authentication 5. PANA Auth Req (EAP-MD5 Challenge) 6. PANA Auth Ans (EAP-MD5 resp) 7. RADIUS Access Req (EAP) 8. RADIUS Access Accept (EAP) 9. PANA Auth Req (EAP Success) 10. PANA Auth Ans (Ack) 11. DHCP Discover 12. DHCP Offer IP Address Allocation 13. DHCP Request (with IP address in 'yiaddr') 14. DHCP Ack 15. IP Session/data traffic EP Filter update based on DHCP snooping

Next Step Provide more details on: The use of link-local IP@ Mechanism to avoid/resolve possible address conflict/collision PANA impacts on DSL network: Host, DSL Modem, DSLAM, BRAS, DHCP server DSLAM acting as EP And the use of DHCP as EP triggering mechanism IP@/Identity binding management Tight/loose coupling between DHCP/PANA/AAA Investigate/clarify the case of hosts behind a NAT/Router in IPv4 Does PANA support NAT traversal? Consider Unspecified IP address? As an alternative to link-local IP address as PRPA

Thank You