IPv4 over IP CS Soohong Daniel Park Syam Madanapalli

IPv4 Convergence Sublayer IPv4 CS is responsible for the transmission and reception of IPv4 packets Classification parameters constitute of IPv4 Header and Transport Header Source and Destination IPv4 addresses Source and Destinations Ports Type-of-Service IP Protocol Filed The following are the list of functions of IPv4 CS Classification of an IPv4 packet to an appropriate MAC Connection Suppression of IPv4 Header, called Payload Header Suppression (PHS) (optional) Delivery of the resulting IPv4 CS PDU to the MAC-CPS SAP to delivery to the peer MAC-CPS SAP. Receipt of the IPv4 CS PDU from the MAC-CS SAP MAC CPS IPv4 CS ULP IPv4

WiMAX Network Architecture P2P MAC Transport Connection always exists between MS and ASN GW MAC connection between MS and BS R6 GRE tunnel between BS and ASN GW Each IPv4 MS is on separate p2p link MS 1 ASN GW MS 2 BS 1 MS 3 MS 4 BS 2 ASN R1R6 R3 Connection WiMAX P2P MAC Transport Connection

Frame Format H: Header Type (1 bit), 0 - Generic MAC PDU E: Encryption Control R: Reserved. Shall be set to zero C: CRC Indicator EKS: Encryption Key Sequence LEN: The Length in bytes of the MAC PDU including the MAC header and the CRC if present (11 bits) CID: Connection Identifier (16 bits) HCS: Header Check Sequence (8 bits) CRC: An optional 8-bit field. CRC appended to the PDU after encryption. Type: This field indicates the subheaders (Mesh subheader, Fragmentation Subheader, Packing subheader etc) and special payload types (ARQ) present in the message payload |H|E| Type |R|C|EKS|R|LEN | | LEN LSB | CID MSB | | CID LSB | HCS | | IPv4 | +- header -+ | | +- and -+ / payload... / | | |CRC (optional) |

Address Assignment Each MS is assigned an unique IPv4 address using DHCP Each MS is assigned an unique IPv4 address using DHCP This may be a private IPv4 address routable only within the service provider network This may be a private IPv4 address routable only within the service provider network NAT support for Internet Connectivity NAT support for Internet Connectivity DHCP is run over initial MAC transport connection DHCP is run over initial MAC transport connection The initial MAC transport connection is established as soon as MS completes its network entry procedures The initial MAC transport connection is established as soon as MS completes its network entry procedures It is p2p connection between MS and AR, hence the DHCP packets reach AR irrespective the DHCP destination address It is p2p connection between MS and AR, hence the DHCP packets reach AR irrespective the DHCP destination address AR shall implement DHCP relay to forward the DHCP request to the DHCP server AR shall implement DHCP relay to forward the DHCP request to the DHCP server

Address Mapping Mapping of multicast IP address to MAC address Mapping of multicast IP address to MAC address MAC address is not used for the data path MAC address is not used for the data path Instead it uses the Connection ID (CID) Instead it uses the Connection ID (CID) Hence no mapping is required Hence no mapping is required

Address Resolution Protocol (ARP) ARP is not required for IPv4 CS, as MAC address is not used for data path. ARP is not required for IPv4 CS, as MAC address is not used for data path. All MSs with IPv4 support SHOULD be configured with a default router (AR) All MSs with IPv4 support SHOULD be configured with a default router (AR) So that all packets will go through the AR and normal routing process So that all packets will go through the AR and normal routing process DHCP should be used to configure the default gateway DHCP should be used to configure the default gateway If an MS tries to do address resolution, the AR should support Proxy ARP as defined in RFC 1027 If an MS tries to do address resolution, the AR should support Proxy ARP as defined in RFC 1027

Next Step Drafting an initial version by November Drafting an initial version by November draft-xxxx-16ng-ipv4-over-ipv4cs-00 draft-xxxx-16ng-ipv4-over-ipv4cs-00 Call for comments (November – December) Call for comments (November – December) Ready for WGLC (December) Ready for WGLC (December) Ready for IESG (January, 2007) Ready for IESG (January, 2007)