DiffServ Resource Management in IPbased Radio Access Networks

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DiffServ Resource ManagementinIP-based Radio
Access Networks

• Geert Heijenk1,2Georgios Karagiannis1Vlora
  Rexhepi1Lars Westberg3
• 1 Ericsson EuroLab Netherlands2 University of
  Twente3 Ericsson Research

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Outline

• IP-based Radio Access Network (RAN)
• Resource Reservation Requirements
• Resource Management in DiffServ (RMD)
• RMD Protocols
• RMD Implementation
• Conclusions Future Work

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IP-based Radio Access Network (RAN)
Base Station
Interior Nodes
Mobile Station
BSC/RNC
Diffserv Domain
Edge Nodes
Radio Access Network (RAN)
Core Network
Public network
Cellular system
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Resource Reservation Requirements (1)

• IP-based RAN has different radio and network
  characteristics and QoS requirements than typical
  Internet
• High cost for transmission links within the Radio
  Access Network
• high volume of leased lines
• base stations spread over a large geographic area
  (far away from the backbone)
• efficient bandwidth utilization
• Specific radio interface characteristics
• Multi-rate channels with bitrate selected
  on-demand
• Radio spectrum utilization requires fast and
  frequent handover operations
• Majority of traffic is transmitted using
  delay-sensitive radio frames
• frequent and fast resource reservation for
  delay-sensitive traffic

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Resource Reservation Requirements (2)

• Specific network characteristics
• RAN is an intranet controlled by one operator
• efficient support of edge-to-edge resource
  reservation
• Majority of the traffic consist of radio frames
  that are transmitted on a unicast and
  bi-directional basis
• efficient support of unicast and bi-directional
  reservations
• traffic from a large number of base stations has
  to be supported by the same transport network
  within the RAN
• the resource reservation scheme needs to be
  scalable

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Resource Management in DiffServ (RMD)An Example
QoS Request forwarded to next hop
QoS Request
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RMD Characteristics

• No per-flow state in the core routersonly
  aggregate state per Per Hop Behaviour
• Only soft stateneeds to be refreshed
• Very simple message processing in core routers
• Interoperable with various external resource
  reservation protocols

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RMD interoperability
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RMD Framework

• designed for edge-to-edge resource reservation in
  a DiffServ based domain
• extends DiffServ with new resource reservation
  concepts and features aiming at
• extreme simplicity
• low cost of implementation
• good scaling properties
• defines two protocol concepts
• Per Hop Reservation (PHR)
• Per Domain Reservation (PDR)

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RMD Protocols
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PDR protocol

• Per Domain Reservation (PDR) protocol manages the
  resource reservation per Diffserv domain
• implements all or a subset of following
  functions
• Mapping of external QoS request to a DiffServ
  Code Point (DSCP)
• Admission control and/or resource reservation
  within a domain
• Maintenance of flow identifier and reservation
  state per flow
• Notification of the ingress node IP address to
  the egress node
• Notification of lost signaling messages (PHR and
  PDR) in communication path
• Notification of resource availability in all
  nodes located in communication path

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Per Domain Reservation

• PDR signaling messages may be encapsulated in
  the PHR signaling messages

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PHR protocol

• Per Hop Reservation (PHR) extends the PHB in
  Diffserv with resource reservation
• reservation-based PHR
• measurement-based PHR
• implements all or a subset of following
  functions
• Admission control and/or resource reservation
  within a node
• Management of one reservation state per PHB
• Measurement of user traffic load
• Stores pre-configured threshold value on maximal
  allowable traffic load (or resource units) per
  PHB
• Adaptation to load sharing
• Severe congestion notification
• Transport of transparent PDR messages

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Reservation-Based PHR
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Measurement-Based PHR
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RMD Implementation
Diffserv Domain with RMD
Sender
Egress
Receiver
Ingress
Interior
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Conclusions

• Current resource reservation protocols can not
  satisfy all the requirements imposed by Radio
  Access Networks
• Resource Management in Diffserv (RMD)
• a simple and scalable solution for resource
  reservation in a single edge-to-edge Diffserv
  Domain
• necessary functionality for interoperability with
  other external resource management strategies
• wide scope of applicability in different Diffserv
  based network types.
• Our prototype implementation shows that RMD is
• Possible to implement
• Scalable
• Interior functionality can be done in hardware

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Future work

• PDR Protocols for specific external protocols
• Measurement-based PHR protocol
• Enhance Reservation-based PHR protocol
• Test RMD in more advanced network topologies

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Some more info

• Three Internet drafts submitted to IETF
• Resource Reservation Issues in Cellular Radio
  Access Networks
• Resource Management in Diffserv (RMD) Framework
• Resource Management in Diffserv On Demand (RODA)
  PHR
• For more info (and subscription to mailing
  list)http//standards.ericsson.net/rmd/
• My email addressgeert.heijenk_at_eln.ericsson.se