IPv6 over 802.16’s IPv6 Convergence Sublayer draft-madanapalli-ipv6-over-802.16-ipv6cs-00 Syam Madanapalli Basavaraj Patil Erik Nordmark JinHyeock Choi Soohong D. Park IETF 66 – Montreal 9-14 July 2006

Agenda Introduction to WiMAX Network Architecture IPv6 over 802.16’s IPv6 CS – Solution Scope of the draft Way Forward

WiMAX Network Architecture ASN GW - Omniscient AR Knows about all nodes attached to itself Only one AR at any given time MAC Transport Connection Always exists between MS and ASN GW 802.16 MAC connection between MS and BS R6 GRE tunnel between BS and ASN GW Initial Service Flow Created as soon as completion of Network Entry Can be used for autoconfiguration MS 1 ASN GW MS 2 BS 1 MS 3 MS 4 BS 2 ASN R1 R6 R3

Proposed Solution IP Link Access Router Prefix Assignment The ASN GW, Multiple BSs attached to the ASN GW and all MS attached to these BSs are all on same IP Link Access Router ASN GW is the first-hop AR Prefix Assignment One or more prefixes are shared among the MSs MS 1 ASN GW MS 2 BS 1 MS 3 MS 4 BS 2 ASN R1 R6 R3 Link

Neighbor Discovery … Router Discovery Periodic RAs Prefix Assignment Send an unsolicited RA as soon as the initial 802.16 transport connection has been established Or just do RS/RA Periodic RAs Send them in unicast manner MaxRtrAdvInterval > 1800 sec. Prefix Assignment One or more prefixes are shared among the nodes on the link Prefixes are advertised with on-link flag (L-bit) reset and autonomous address-configuration flag (A-bit) set Next-Hop Always the ASN GW for an MS An intelligent implementations need not perform this No direct communication is allowed between two MSs

Neighbor Discovery Address Resolution NUD Redirect Hop Count Not required But the existing implementations may attempt address resolution AR just ignores the NS After no response, MS sends the packet to the AR, the default router NUD Required because an MS may have more than one IPv6 address Can be performed as specified in 2461bis Redirect ASN GW should not redirect for the packets destined to the same IP Link Hop Count Should not be decremented for the on-link communication

Address Autoconfiguration Interface Identifier generation Generate the IID from MS’s 48-bit MAC address as per RFC2464 Optionally, it is allowed to use Privacy Extensions as specified in RFC 3041 Duplicate Address Detection MS behavior is as specified in 2462bis DAD is performed using Relay DAD

Relay DAD ASN GW Maintains Address Cache List of IPv6 addresses that are currently in use including solicited-node multicast addresses. Learns the addresses from DAD NS, if the address is not duplicate Learns the Solicited-Node Multicast Addresses from MLD Join Relays the DAD Probe if there is a match in the address cache for the destination solicited node multicast address MS responds to the DAD Probe if the address is duplicate Address Cache entries expire when Prefix life time expires MS or another entity deregisters explicitly R6 GRE tunnel for the MS is deleted NS/NA exchange with longer intervals

Issues Address Cache overflow Loss of DAD Probe AR should limit the no. of addresses an MS can have at any given time Loss of DAD Probe Do we need to dealt with it? Tunnel between BS and AR Should be per MS for IP CS

Scope of the document Current scope covers only WiMAX Network Architecture Should 16ng consider other deployment scenarios? Should this document cover the other scenarios? Or WG allows writing another draft?

Way Forward Include other deployment scenarios? Accept as WG document?