Transcript Presentation Template for Telcordia Technologies

Integrating QoS Support in
the Dynamic Mobility
Agent (DMA) Architecture
DIMACS Workshop,
Feb. 8, 2001,
Rutgers, NJ.
An SAIC Company
A. Misra, S.Das, A. McAuley and A. Dutta
Telcordia Technologies, USA
S.K.Das
University of Texas at Arlington, USA
Introduction
 Higher bandwidth packet-based technologies are
emerging, such as, GPRS, EGPRS and UMTS2000
 Next generation cellular networks will not only
support users with different bandwidth guarantees
but also transport multimedia traffic with diverse QoS
constraints
 End-to-end QoS guarantees for mobile users are
desirable
©Telcordia Technologies Inc., 2001.
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IP Mobility Management-State of the Art
 Solutions such as MIP (Mobile IP) and SIP-based
mobility provide basic ubiquitous connectivity.
– Use of temporary care-of addresses (CoA) to redirect packets
without modifying the fundamental routing fabric.
 Newer solutions such as HAWAII, CIP, MIP-RR and
IDMP provide hierarchical mobility management.
– Use either specialized host-based routing or multiple CoAs to
provide a more stable CoA to external hosts.
 Integration with an IP-level QoS architecture is
missing.
– Need to provide load-balancing and QoS-assuring features to
mobile nodes (MNs).
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Wireline IP QoS Architectures…1
 Two wireline-oriented mechanisms for supporting IP-based QoS
guarantees.
– Integrated Services (Intserv)
 Reservation of resources on a per-flow (fine) granularity, with intermediate
nodes maintaining reservation state.
– Differentiated Services (Diffserv)
 Coarser classification at the network edge, followed by class-based
(stateless) differentiation in the core.
 Multi-Protocol Level Switching (MPLS) provides the ability to
control the path of traffic through an IP network.
– Resource reservation is easier when not just the traffic load, but its
path, is well-established. is also emerging as a standard for traffic
flows via Internet
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Wireline IP QoS Architectures…2
 The Bandwidth Broker (BB) architecture has been
proposed for dynamic admission control and
resource provisioning.
– Centralized agent maintains knowledge of the link capacities and
link loads within the domain.
– Workable for small-to-medium sized domains.
 Little work on architectures that integrate QoS and
mobility management in next generation wireless IP
networks.
Key issue is the need for dynamically signaling the changing load
levels on a path as MNs change their point of attachment.
©Telcordia Technologies Inc., 2001.
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Overview of the Basic DMA Architecture
Home Network
/Domain
MA
CN
DHCP/DRC
P
3
2
1
2
1
MN
Visited Network/Domain
 During the initial subnet-level configuration process (via DHCP/DRCP
or from an SA), MN receives a Local Care-of Address (LCoA) and the
address of a Mobility Agent (MA).
 The MA associated with this MN remains the same throughout its stay
in this domain. The MA provides the MN with a stable globally valid
care-of address (GCoA), which ensures global reachability.
©Telcordia Technologies Inc., 2001.
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Overview of IDMP
 Our protocol for performing the intra-domain mobility
management (with QoS, of course!).
 Two options for getting a GCoA.
– Shared GCoA—All MNs assigned to an MA use the MA’s address as
their GCoA. This mandates external tunneling (from the Internet to
the MA).
– Unique GCoA- MA assigns each MN a unique GCoA from an
address pool. MA is then responsible for intercepting packets
addressed to that pool- removes the need for external tunneling.
 Provides IP-level support for
– Multicasting-based fast handoffs: packets are buffered at the new
point of attachment and are available immediately after subnet-level
configuration.
– Paging: MA will multicast a solicitation for an idle MN that is still in
that domain.
©Telcordia Technologies Inc., 2001.
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IDMP Overview (SA Mode)
Home Network
/Domain
MA
CN
SA
3
2
1
2
1
MN
Visited Network/Domain
 MN receives two addresses from Subnet Agent (SA).One is for Local
Care-of Address (LCoA) and the other one is MA. On every change in
subnet, the MN interacts with the SA to obtain a new LCoA.
 SA is responsible for demultiplexing all packets tunneled to SA’s interface
address and forwarding them to individual MN using layer-2 mechanisms > no transmission of tunneled messages on the wireless interface.
©Telcordia Technologies Inc., 2001.
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IDMP Overview (CO Mode)
Home Network
/Domain
MA
CN
DHCP/DR
CP
3
2
1
2
1
MN
Visited Network/Domain
 MN receives two addresses from additional subnet level configuration
protocols, such as DHCP or DRCP.One is for Local Care-of Address
(LCoA) and the other one is the MA’s address.
 In this mode MN is responsible for decapsulating packets destined to it ->
tunneling over the wireless link. Also, not feasible to provide QoS support
with this mode.
©Telcordia Technologies Inc., 2001.
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Message Flow in SA Mode
MA
SA
MN
HA/SIP
Server
ADVERTISEMENT
REG. REQUEST
REPLY
REG. REQUEST
REPLY
UPDATE
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Message Flow in CO Mode
DHCP/DRCP
Server
MN
MA
DISCOVER
HA/SIP
Server
OFFER
REG. REQUEST
REPLY
UPDATE
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The QoS framework of DMA

An MN specifies its QoS requirements only during the initial
registration in the domain.
–
–

No support yet for subsequent renegotiation of QoS.
QoS profile transferred by MA to the SA at the new point of
attachment.
Bandwidth Broker architecture is used to centralize the dynamic
management of resources for different service classes.
–

As MNs move, the corresponding MA interacts with the BB to set up
resources as needed.
DMA splits the end-to-end QoS management into two distinct
parts:
–
–
–
Global QoS framework which uses Diffserv/MPLS framework
Intra-domain QoS framework also based on Diffserv/MPLS.
By providing reservations and guarantees on aggregates, we reduce
the QoS signaling load.
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Functional QoS Architecture
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Signaling Flow for QoS in IDMP/DMA
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Some Additional Considerations

Pre-configuration
– For services requiring lower latency in the re-establishment of
QoS guarantees, the MA can perform pre-configuration to
neighboring SAs
– MA can preemptively multicast the MN’s traffic and QoS
parameters to the set of neighboring SAs

On-Demand
– When MN moves from its initial point of attachment within a
domain, the new serving SA must be configured with MNspecific traffic descriptor and conditioner parameters
– MA may need to request the BB to reserve additional
resources over the new path
©Telcordia Technologies Inc., 2001.
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Further Considerations

Admission Control Choices
–
–

Network must ensure that adequate bandwidth is available over the
new path in conformance to the specified QoS bounds
Network operator can choose different admission control strategies for
each service class
QoS for Mobile Nodes: We are currently concentrating
on two models:
–
–
In simpler model, users are simply distinguished by differential
bandwidth guarantees. A single user has a single QoS profile.
In advanced model, users are distinguished not simply by the
negotiated traffic rate, but also by the bounds associated with
performance –related metrics, such as, packet jitter or loss. Individual
users have multiple QoS profiles.
©Telcordia Technologies Inc., 2001.
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IDMP Message Extensions

Subnet Registration_Request
–

Extended to include QoS-specific extensions, such as peak rate and
desired packet delay
Subnet Request_Reply
–

Extended to allow an SA to specify multiple MA addresses to an MN,
as well as QoS extensions.
Intra-domain Location_Update
–

Extended to allow an MN to specify the requested QoS parameters
to the candidate MA
Intra-domain Location_Reply
–
Extended to allow an MA to specify the assigned QoS parameters to
an MN
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One Class-per MA Architecture

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Multiple GCoA-based QoS Architecture

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Single GCoA-based QoS Architecture

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Additional QoS-related Considerations
 The DMA architecture does not employ dynamic host-based
routing.
– An MPLS FEC can simply be designed based on the destination
LCoA pool—the LCoAs reflect the subnet of attachment.
– In contrast, solutions such as HAWAII or CIP require each
intermediate router to consult its forwarding table. Harder to set up
“fast paths” in such an environment.
 DMA essentially treats the cellular domain as a separate
Diffserv domain.
– Use of MPLS with the BB-based mechanism will be explored.
– At the very least, the BB approach should be scalable to a “domain”
with O(1000) MNs.
©Telcordia Technologies Inc., 2001.
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Implementation Status
 Basic IDMP functionality implemented and tested in Linux.
– Currently uses MIP for global binding.
 The BB functions developed and tested as part of separate
project.
– Communication with BB via CORBA; communication between BB
and routers via rcp.
 QoS extensions to IDMP currently being implemented and
tested on our testbed.
– Main piece of unfinished work is the development of the Mobility
Server (MS).
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Conclusion
 DMA: An architecture for supporting QoS guarantees in next
generation IP-based wireless networks.
– IDMP for two-level hierarchical mobility management.
– BB-based dynamic resource provisioning for a Diffserv-based
cellular domain.
 QoS based on the introduction of new functionality in elements
such as the MA and SA, and the specification of the MS.
– MN signals QoS profile only on first registration; subsequent
negotiation not needed.
– MS implements a dynamic QoS-aware MA assignment algorithm for
load balancing.
– Suited to introducing MPLS-based “fast paths” in the cellular
domain.
 Different MA assignment architectures explored for different
QoS-based mobility service scenarios.
©Telcordia Technologies Inc., 2001.
February 7, 2001
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Publications
 S. Das, A. Misra, P. Agrawal and S. Das, “TeleMIP: Telecommunication
Enhanced Mobile IP architecture for Fast Intra-Domain Mobility”, IEEE
PCS Magazine, August 2000.
 A. Misra, S. Das, A. Mcauley, A. Dutta and S. K. Das, “IDMP: An IntraDomain Mobility Management Protocol using Mobility Agents”, <draftmisra-mobileip-idmp-00.txt>, Work in Progress, July 2000.
 A. Misra, S. Das, A. Mcauley, A Dutta and S. K. Das, “Introducing QoS
Support in TeleMIP’s Mobility Architecture”, Proceedings of IEEE
International Conference on Personal Wireless Communications,
December 2000, Hyderabad.
 K. Chakraborty, A. Misra, S. Das, A. Mcauley, A Dutta and S. K. Das,
“Implementation and Performance Evaluation of TeleMIP”, to appear in
Proceedings of ICC, June 2001, Helsinki.
 A. Misra, S. Das, A. Mcauley, A Dutta and S. K. Das, “Supporting Fast
Handoffs and Paging in IDMP”, to appear in Proceedings of 3G
Wireless 2001 Conference, June 2001, San Francisco.
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