1. DS-Lite for Point-to- Point Access Network IETF 78 Maastricht 2010 July 30

2. 2 Objectives Address v4 exhaustion in Point-to-Point network Identify v4 hosts when there is address overlapping in plain IP-in-IP tunnel Offer v6 service to customers before the access network has been upgraded to v6.

3. 3 Ideas DS-Extra-lite suggests to use L2 id (eg. vlan tag or circuit id) to identify the customers in the point-to-point network instead of using IPv6 address. This relaxes the requirement to upgrade the access network to v6 for DS-lite. The Edge Router uses the point-to-point id to map it to an IPv6 Flow Label and creates a softwire to the AFTR. The IPv6 Flow Label is the Context-Id used in GI-DS-Lite.

4. Architecture Host 1 CPE A AN Edge Router IPv6 IPv4 network AFTR Softwire tunnel Host 2 Host 3 Host 4 Map IPv6 Flow Label to CID CPE B NAT Mappings: (Flow Label, TCP port1 a.b.c.d, TCP port2) Pt-to-Pt unnumbered I/F Access CPE A and B use 192.168.1.0/24.5.6

5. 5 Procedure CPE will act as a DHCP server handing out RFC1918 addresses. CPE won’t perform the NAT function. Instead, it will forward the packet to the point-to-point circuit to the ER. ER maps the point-to-point circuit to the IPv6 Flow Label. ER creates a softwire to the AFTR using the IPv6 Flow Label as the CID. ER forwards the packet to the AFTR over the softwire. AFTR receives the packet, decapsulates the IPv6 header, and performs the NAT-44 function.

6. 6 CPE Management Some operators using RFC1918 to manage devices (eg, STB, ATA) behind the CPE. This model can stay unchanged. When the ER receives the packet from the management prefix, it will not forward the packets into the softwire. Instead, the ER will forward the packets to its internal management network.

7. 7 Offer IPv6 to the CPE The encapsulation procedure can be used to support IPv6 deployment in the CPE. The ER will assign a /64 prefix over the point-to-point circuit. The CPE will advertise the IPv6 prefix to the hosts. The ER is the default v6 router of the CPE.

8. Q & A Questions? Any interest?