Transcript IP CL - ComNets

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
Presentation Outline
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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
IP Convergence Layer for HIPERLAN/2
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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
IP network layer
CL SAP
Packet based Convergence Layer
Part 2: SSCS Part
Ethernet
Service Specific
Convergence
Sublayer
IP
1394
Service Specific
Service
Convergence
Part 1: Common
Part Specific
Convergence
Convergence
Sublayer
for IP
Sublayer
Sublayer
Part 1: Common Part
Common Part Convergence Sublayer
Segmentation and Re-assembly
DLC SAP
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 …
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
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.
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
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
QoS Management on HIPERLAN/2 IP CL
Classification
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•Packet length
•QoS parameter
...
ICI generation
N-2 N-1 N
IP
Scheduling (IP)
Low Priority
High Priority
SAR + Buffering
CL
Flow control
Mapping (N -> L)
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Scheduling
(Link Layer)
Low Priority
H/2 DLC
L-1 L
High Priority
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
Radio Handover
APT
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APC
Core
Network
APT
Network Handover
Core
Network
APT
APC
APT
APC
APT:
APC: Access
Access Point
Point Transceiver
Controller
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 MTrepresentative towards IP
network
• and AP as proxy towards MT
Mobile IP
SSP
Cellular IP
SSP
Common Part
Control Plane
User Plane
Netw. Handover Integration - Example
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CL in AP serves as MT-representative
Re-routing of packets from old to new AP
MT------------------ AP ---------------------------------------- Network
MT_Assoc iated_with_old_AP
MT_Absenc e
c onveying old AP-ID
rec eiving new MAC-ID
AP_old_Route_Update
HO_Assoc iation
Backbone Signalling
AP_AP_NW_HO
HO_Link_Capability
Handover_Com pletion
IP c omm unic ation resum es
HO_Com plete
AP_new_Route_Update
Cellular IP Routing
updated by CL
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
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
QoS Mapping
Connection-less QoS
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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
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