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Softwires Hub & Spoke Deployment Framework with L2TPv2. draft-ietf-softwire-hs-framework-l2tpv2-00.txt. Guidelines for using L2TPv2 as the Softwires H&S Solution. Overview of the L2TPv2 Solution Description of how it meets the Softwires H&S requirements
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Softwires Hub & Spoke Deployment Framework with L2TPv2 draft-ietf-softwire-hs-framework-l2tpv2-00.txt
Guidelines for using L2TPv2 as the Softwires H&S Solution • Overview of the L2TPv2 Solution • Description of how it meets the Softwires H&S requirements • Outline of how L2TPv2 can support each of the deployment scenarios mentioned in the problem statement • Details on: • Provisioning • L2TPv2 tunnel and session usage • PPP usage • IPv6 Neighbor discovery • DHCP • AAA
Overview of the L2TPv2 Solution • L2TPv2 is RFC2661 • Use the voluntary tunneling model • End user client initiates the tunnel • SI takes the LAC role • SC takes the LNS role • Single L2TP session per tunnel • A PPP session within each L2TP session
How L2TPv2 meets the Softwires H&S Requirements • draft-ietf-softwire-problem-statement-02 • List each of the requirements and describe how L2TPv2 meets them. • Widely implemented and integrated with existing SP infrastructure • Runs over UDP • Supports bi-directional authentication • Can run with IPsec
How L2TPv2 supports the deployment scenarios • Problem statement outlines four deployment scenarios • The use of L2TPv2 and supporting protocols is described for each scenario • Both IPv6 over IPv4 and IPv4 over IPv6 are discussed.
IPv6 over IPv4 Softwire with L2TPv2:Router CPE as Softwire Initiator SC LNS Dual AF CPE IPv4 IPv6 o PPP L2TPv2 o UDP o IPv4 IPv6CP: capable of /64 interface ID assignment or uniqueness check /64 prefix RA /48 prefix DNS, etc /64 prefix DHCPv6 RA DNS, etc DHCPv4/v6
The Provisioning Model • Recommendations for address assignment • In general IPv6 addresses should be globally routable • Exceptions exist • Recommendations for prefix delegation • Length of IPv6 prefixes should be a multiple of 4
L2TPv2 Tunnel/Session Usage • L2TPv2 must run over UDP for Softwires • Outline control flow for tunnel establishment • SCCRQ, SCCRP, SCCCN • Outline control flow for session establishment • ICRQ, ICRP, ICCN • Recommendations for the use of AVPs within the control messages. • Don’t require tunnel authentication • Simpler to rely on PPP authentication
L2TPv2 Tunnel/Session Usage (cont) • Many AVPs are irrelevant for Softwires • When they are mandatory we recommend a value for the sender • We require that the receiver ignore them • Recommend the use of the L2TP Hello message for tunnel maintenance
The PPP connection • Each L2TPv2 session contains a PPP session • We require that CHAP (RFC1994) authentication be supported • PPP authentication is optional if configured by the SC administrator • IPv6CP (RFC2472) must be used to exchange the Interface Identifier • IPv4CP (RFC1332) should be used to obtain an IPv4 address
Neighbor Discovery • The IPv6 SI must send a Router Solicit message after IPv6CP • The IPv6 SC must respond with a Router Advertisement containing the IPv6 prefix of the PPP link
DHCP • DHCPv6 is used for prefix delegation for IPv6 (RFC3633) • DHCPv4 is recommended for prefix delegation for IPv4 • draft-ietf-dhc-subnet-alloc-03
AAA • Use of RADIUS attributes in address assignment • IPv6 • Framed-Interface-Id (RFC3162) • Framed-IPv6-Prefix (RFC3162) • IPv4 • Framed-IP-Address(RFC2865)
Still some sections to complete. • MIBs • Security (as relates to the security draft) • Accounting – perhaps another draft • ???