Transmission of IP Packets over Ethernet over IEEE802.16 draft-riegel-16ng-ip-over-eth-over-80216-00

1
Transmission of IP Packets over Ethernet over
IEEE802.16draft-riegel-16ng-ip-over-eth-over-8021
6-00

• Max Riegel ltmaximilian.riegel_at_siemens.comgt
  2006-07-07

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Introduction

• Goal of this presentation
• Present draft-riegel-16ng-ip-over-eth-over-80216-0
  0.txt
• Introduce topic and particular issues with
  Ethernet over IEEE802.16
• Provide background information on IEEE802.16 link
  behavior
• Outline solution approaches
• Promote contributions from others
• Status of draft-riegel-16ng-ip-over-eth-over-80216
  -00.txt
• Initial I-D
• Provides outline and hints, how the solution may
  look like
• IPv4 solution based on results out of WiMAX NWG
• Lots of material still missing

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IP works fine over Ethernet
Internet

• RFC 894 defines transmission of IPv4 packets over
  Ethernet
• RFC 826 recommends the use of ARP for address
  resolution
• RFC2464 specifies the transmission of IPv6
  packets over Ethernet
• Today most Ethernets are (bridged) switched LANs
  with point-to-point links between Switch and Host
• No issues when there is sufficient bandwidth and
  power
• Usually the case for wired Ethernets
• Wireless issues shared transmission resource and
  limited power.
• Power issue may even be more critical than scarce
  transmission resource

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Protocol Layering of the IEEE 802.16 Standard

• Physical Layer, MAC Common Part Sublayer and
  Management/Control Plane are agnostic to user
  payload (CS type)
• Standard accommodates multiple instantiations of
  CS types
• Classification is specific to particular CS type
• e.g. for IPoETH-CS, 14-18 bytes of additional
  header information must be parsed per packet.

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Convergence SublayerClassification
Encapsulation

• Packet-handling in the base station is done based
  on information in the packet header

Classification based on header information
Encapsulation and forwarding
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The IEEE802.16 Link Model
APPL
APPL
APPL
IEEE802.16/802.16e Data/Control Plane
CS SAP
Service Specific Convergence Sublayer (CS)
Classifier
CID6
CID4
CID2
PHS (opt.)
MAC SAP
MAC
MAC Common Part Sublayer (MAC CPS)
Privacy Sublayer
Radio
PHY SAP
Physical Layer (PHY)
PHY
BS
MS
MS
MS

• IEEE802.16 provides point-to-point links between
  the BS and MS
• No direct communication between terminals
  possible
• Fits well into switched Ethernet model

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Switched Ethernet link model for IEEE802.16
APPL
APPL
APPL
IEEE802.16/802.16e Data/Control Plane
CS SAP
Service Specific Convergence Sublayer (CS)
Classifier
CID6
CID4
CID2
PHS (opt.)
MAC SAP
MAC
MAC Common Part Sublayer (MAC CPS)
Privacy Sublayer
Radio
PHY SAP
Physical Layer (PHY)
PHY
BS
MS
MS
MS

• Switch in basestation broadcasts packets to all
  MSs, if destination MAC address is not known in
  the switch
• Waste of radio resource
• All terminals have to wake up to process
  broadcast packet

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Enhanced Ethernet link model for IEEE802.16
APPL
APPL
APPL
IEEE802.16/802.16e Data/Control Plane
CS SAP
Service Specific Convergence Sublayer (CS)
Classifier
CID6
CID4
CID2
PHS (opt.)
MAC SAP
MAC
MAC Common Part Sublayer (MAC CPS)
Privacy Sublayer
Radio
PHY SAP
Physical Layer (PHY)
PHY
BS
MS
MS
MS

• Dedicated switch functions prevent the
  unnecessary transmission of ETH frames over the
  air
• Response to broadcast and multicast requests on
  behalf of the MSs
• Must learn about the MAC IP addresses of the MSs

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IPv4 specific behavior of the bridging function

• Proxy ARP function
• The BS SHALL support Proxy-ARP.
• The BS SHALL have the ability to enable or
  disable Proxy ARP. If Proxy ARP is disabled, the
  ARP Proxy Agent shall pass all ARP packets
  without discrimination or modification using
  Standard Learned Bridging.
• Upon receiving an ARP Request from a network side
  interface, the ARP Proxy Agent shall unicast an
  ARP Response back to that interface, provided
  that the target address matches an entry in the
  Proxy ARP table. If no match is found in the
  Proxy ARP table, the ARP Proxy Agent SHALL
  support silently discarding the Request or
  flooding the Request to all radio connection
  interfaces based upon configuration option.
• The ARP Proxy Agent shall pass all ARP Response
  packets without discrimination or modification
  using Standard Learned Bridging. Upon receiving
  an ARP Request from an radio connection
  interface, the ARP Proxy Agent shall unicast an
  ARP Response back to the interface provided that
  the target address matches an entry in the Proxy
  ARP table. Otherwise, the ARP Proxy Agent shall
  flood the Request to all network side interfaces.
• The ARP Proxy Agent shall silently discard any
  received self-ARP Requests. Those are requests
  for a target IP address, that when queried in the
  Proxy ARP table results in a response MAC equal
  to the Request's source MAC address.
• The ARP Proxy Agent shall issue a gratuitous ARP
  on the network side interfaces for any new
  addition to the Proxy ARP table. An unsolicited
  broadcast ARP Response constitutes a gratuitous
  ARP. The Proxy ARP table MAY be established out
  of other IPv4 specific information available in
  the BS, e.g. DHCP Proxy or MIPv4 FA. The
  particular procedures are implementation
  dependent.
• Information for the Proxy ARP Table MAY be
  transferred during handover of a mobile
  IEEE802.16e station to the target BS. The
  particular protocol for transfer of information
  for the Learned Bridge Table is out of scope of
  this specification.

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IPv6 specific behavior of the bridging function

• t.b.f.

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Conclusion

• Current specification makes no use of MBS feature
  of IEEE802.16 MAC
• MBS may not provide essential benefits for
  supporting multicast
• Power consumption issue may be more important
  than radio resource issue
• Proxy functions in bridge at BS may gain more
  than enhancements to the multicast behavior of
  IEEE802.16
• Need for context transfer between proxy tables
  during handover
• Learned table entries may efficiently be reused
  by the target BS
• Open context transfer protocol

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Questions Comments

• ?