IP%20Convergence%20Layer%20for%20HIPERLAN/2

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IP Convergence Layer for HIPERLAN/2

• Workshop IP in Telekommunikationsnetzen
• 25./26. Januar 2001, Bremen

Servane Bonjour, France Telecom Philippe Bertin,
France Telecom Sven Hischke, Deutsche
Telekom Arndt Kadelka, Aachen University of
Technology Andreas Krämling, Aachen University of
Technology Matthias Lott, Siemens AG Mark West,
Roke Manor Research
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Presentation Outline

• Transfer of IPv4 and IPv6 Packets
• Address Management
• Header Compression
• Quality of Service with HIPERLAN/2 IP CL
• Network Handover
• Stand-by Mode Support
• Conclusion

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IP Convergence Layer for HIPERLAN/2

• Goal to efficiently transfer IP packets on an
  H/2 radio link with QoS and handover management
• Common part convergence layer is defined in the
  H/2 standard
• Ethernet and 1394 service specific convergence
  sub-layers are defined in H/2 standard
• Need of an IP service specific convergence
  sub-layer for H/2

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Transfer of IPv4 and IPv6 Packets

• Variable IP packet size versus fixed sized DLC
  PDUs
• SAR function (already defined in the H/2
  standard)
• Mapping of both connection-less and /-oriented
  services (IP) to connection-oriented service
  (H/2)
• Need of additional information attached to each
  IP packet
• Interface Control Information (ICI) with
• hardware destination address
• QoS identifier or QoS parameters
• packet size

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Header Compression

• Goal Efficient use of the scarce radio resources
  by reducing the header overhead of IP packets
• For VoIP applications the overhead is in the
  order of several hundred percent
• Existing header compression schemes (e.g. RFC
  1144, RFC 2508) do not perform well on HIPERLAN/2
• A new scheme has to be developed which deals with
  high error rates or long roundtrip times on the
  wireless link
• An IETF draft from the ROHC (RObust Header
  Compression) working group describing an
  IP/UDP/RTP header compression scheme exists

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Address Management

• Goal to maintain a mapping between the H/2 DLC
  addresses (MAC-ID) and the addresses sent by the
  IP-to-wireless interface.
• Use of static hardware addresses either IEEE 802
  or EUI-64.
• Definition of a table to map hardware addresses
  and H/2 MAC identifiers (MAC-ID). This avoids to
  transfer the hardware address with each IP packet
  and consequently reduces the frame overhead.
• Mapping of IP unicast, multicast, anycast and
  broadcast addresses to DLC unicast, multicast and
  broadcast addresses.

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Quality of Service on HIPERLAN/2 IP CL

• Motivation
• Provide transparent QoS for end-to-end
  connections
• Needed for multimedia applications with real-time
  requirements
• Requirements
• Resource reservation and control (connection
  admission control)
• QoS type negotiation during association
• Re-negotiation owing to changed available
  resources (e.g. handover, increased interference,
  fading, ...)
• Mapping of priority scheme of IP layer to
  priority scheme of DLC layer
• Flow-control and information on QoS violations to
  IP layer

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QoS Management on HIPERLAN/2 IP CL

• Functions of the H/2 IP CL
• Agreement of QoS parameters defined on the IP
  layer and supported by the CL during
  configuration process
• ICI (interface control information) contains
  information on QoS parameter of IP packet
• Mapping table is managed in the control plane
• By means of the mapping table the packets can be
  assigned to the respective queues (user plane)
• Queues on the data link control layer (DLC) are
  accessed by respective SAP (service access point)
• On DLC layer each QoS context is identified by a
  DLCC-ID

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QoS Management on HIPERLAN/2 IP CL
Classification
IP

• Packet length
• QoS parameter
• ...

Scheduling (IP)
High Priority
Low Priority
ICI generation
SAR Buffering
CL
Flow control
Mapping (N -gt L)
H/2 DLC
1 L-1 L
Scheduling (Link Layer)
High Priority
Low Priority
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Handover Requirements on IP CL

• BRAIN considers several handover types
• radio handover(staying at one access point)
• served completely at radio access(in DLC layer)
• IP CL not involved
• horizontal and vertical network handover(moving
  to a different access point)
• interworking with network (adaptation by IP CL)
• requires means to minimize packet loss during HO
  execution (queuing, re-routing, re-sequencing,
  etc.)
• handover type performed should not show
  significant difference in QoS

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Network Handover Concept

• IP CL supports various IP mobility concepts
  (e.g., Mobile IP, Cellular IP)
• Functional split in CL control plane

• IP CL Common Part (IP CL CP)
• forwarding of MT (CL DLC) specific data to new
  AP
• tunneling of packets from old to new AP
• IP CL Service Specific Part (IP CL SSP)
• adaptation to Cellular IP, Mobile IP, or new IP
  mobility protocols
• AP may serve as MT-representative towards IP
  network
• and AP as proxy towards MT

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Netw. Handover Integration - Example

• CL in AP serves as MT-representative
• Re-routing of packets from old to new AP

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Stand-by mode support

• 2 terminal states handled at the link layer
• active full link layer connectivity, support
  data connections
• stand-by monitoring of paging information only
• IP Convergence Layer implementation
• need for introducing a stand-by mode in H2, e.g.
  relying on multicast and broadcast user data
  channel used by the CL
• Procedure in the AP
• periodically broadcast paging area identifier
• when needed, multicast paging request to stand-by
  MTs
• Procedure in the MT
• switch between active and stand-by modes through
  association and disassociation procedures
• monitors paging area id and paging request when
  in the stand-by mode

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Conclusion

• Basis for IP convergence layer for HIPERLAN/2
  defined
• BRAIN IP CL for H/2 aligned with the concepts
  defined in IP2W
• Further work to evaluate solutions for
• QoS management
• Network handover control

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QoS Mapping

• Connection-less QoS
• No QoS guarantee (no bandwidth reservation
  possible)
• Defined within IP by Differentiated Services
  (DiffServ)
• DiffServ code points (DSCP) define per hop
  behavior (PHB)
• DSCP is mapped to respective QoS parameter on
  HIPERLAN/2
• e.g. Ethernet priorities (8 priorities aligned
  with Ethernet SSCS)
• Connection-oriented QoS
• QoS can be guaranteed (as far as possible in
  wireless systems)
• Defined within IP by means of IntServ/RSVP
• Bandwidth reservation (including connection
  admission control) based on RSVP (FLOWSPEC
  parameters in Resv message)
• Connection end-point identifier (CEP-ID) is
  established for that flow between CL and IP layer

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QoS Mapping

• Connection-oriented QoS
• QoS can be guaranteed (as far as possible in
  wireless systems)
• Defined within IP by means of IntServ/RSVP
• Bandwidth reservation (including connection
  admission control) based on RSVP (FLOWSPEC
  parameters in Resv message)
• Connection end-point identifier (CEP-ID) is
  established for that flow between CL and IP layer