IPv4 over 802'16 IP CS

1
IPv4 over 802.16 IP CS

• Soohong Daniel Park
• Syam Madanapalli

2
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

3
WiMAX Network Architecture

• P2P 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
• Each IPv4 MS is on separate p2p link

4
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

0 10 1 2 3 4 5 6 7 8 9 0 1 2 3
4 5----------------HE
Type RCEKSRLEN ------------
---- LEN LSB CID MSB
---------------- CID LSB
HCS ---------------
- IPv4 -
header -
- and -/
payload ... /-
-
----------------CRC
(optional) --------
5
Address Assignment

• Each MS is assigned an unique IPv4 address using
  DHCP
• This may be a private IPv4 address routable only
  within the service provider network
• NAT support for Internet Connectivity
• DHCP is run over initial MAC transport connection
• 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
• AR shall implement DHCP relay to forward the DHCP
  request to the DHCP server

6
Address Mapping

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

7
Address Resolution Protocol (ARP)

• 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)
• So that all packets will go through the AR and
  normal routing process
• 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

8
Next Step

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