Signaled Provisioning of the IP Network Resources Between the Media Gateways in Mobile Networks

1
Signaled Provisioning of the IP Network
Resources Between the Media Gateways in Mobile
Networks

• Leena Siivola
• 10.12.2004

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Problem Description

• For circuit switched (CS) traffic the delay and
  the jitter requirements are strict. That is why
  the amount of voice calls must be controlled not
  only from radio networks (RN) side but also from
  IP multiservice backbones point of view.
• The backbone edge nodes, i.e. the Media Gateway,
  must have ways to control the amount of traffic
  injected to the network
• This must make it possible to give some QoS
  guarantees for the voice calls
• The network resources will be used more
  efficiently

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Objectives and Scope

• The objective of this Thesis is to
• describe the current Call Admission Control (CAC)
  mechanisms in the 3G IP multiservice backbone
• to evaluate the suitability of the NSIS signaling
  protocol framework for the CAC solution.

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The functional architecture of the 3G network
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The Call Admission Control Mechanism
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Provisioning Methods in the IP Multiservice
Backbone
.
.
MBAC Measurement Based Admission Control MPLS
Multiprotocol Label Switching
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Static Provisioning Methods in the Media Gateway
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Signaled Provisioning

• Signaled provisioning is a tempting approach for
  CAC because it can give hard QoS guarantees for
  traffic flows and it can increase the network
  utilization.
• Many QoS signaling protocols exist
• Tenet ST-II
• RSVP with its extensions
• YESSIR (Yet another Sender Session Internet
  Reservations)
• Boomerang
• RSVP has been the most famous one
• Has said to bee too complex and suffering
  scalability problems
• -gt also other simulation results exist!
• The work with the NSIS signaling protocol
  framework was started, because there was a need
  for a more lightweight signaling protocol.

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The NSIS Signaling Framework
NSLP NSIS Signaling Application Level NTLP
NSIS Transport Level
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The NSIS Signaling for Quality of Service (QoS)

• The NSIS QoS signaling framework is based on a
  two layered architecture
• NTLP (NSIS Transport Layer Protocol)
• NSLP (NSIS Signaling Layer Protocol)
• QoS Model that is being signalled (e.g. Intserv
  or RMD)
• NSIS without QoS Model is only a framework with
  many optional features.

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Comparison Between the NSIS QoS Signaling and RSVP

• NSIS can be both sender- and receiver-oriented
• NSIS does not support multicast
• Mobility support
• Bi-directional reservation possible

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NSIS(RMD) Architecture

• It is not possible to evaluate the NSIS signaling
  without taking the QoS model into account. The
  NSIS framework consists of several optional
  features that can be taken into use.
• Resource Management in Diffserv (RMD)
  implemented with NSIS

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Successful Reservation
Receiver
Edge
Initiator
Edge
Interior
Interior
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One Possible Implementation of NSIS to the 3G
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Evaluation

• NSIS framework is flexible and modular
• -gt it can be used in different ways
• There are several optional features that can be
  taken into use
• The resulting QoS protocol is even more complex
  than RSVP
• -gt what do we gain with the abstraction level?

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Evaluation The NSIS(RMD) Implementation as an
Example

• Evaluation criteriors
• Per-hop Performance Metrics
• Signaling message processing delay
• Per-Reservation Performance Metrics
• Signaling Bandwidth Overhead
• Abortive Provisioning
• Blocking Probability
• Reservation Setup Time
• Applicability of the NSIS(RMD) Signaling to the
  IP Multiservice Backbone

SCALABILITY AND ROBUSTNESS
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Per-hop Performance Metrics Signaling message
processing delay

• ts signaling message processing delay
• tS0 the base parameter
• fR a component dependent of the session load
  (LR)
• fT a component dependent of the session (LR)
  and the signaling load (LT)
• Signaling message processing delay
• In the edge routers proportional to the number
  of sessions
• In the core routers a constant

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Per-Reservation Performance MetricsSignaling
Bandwidth Overhead
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Per-Reservation Performance MetricsAbortive
Provisioning
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Per-Reservation Performance MetricsBlocking
Probability
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Per-Reservation Performance MetricsReservation
Setup Time
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Conclusions

• The Intserv type (RSVP-like) per-flow end-to-end
  signaling brings nothing new when comparing to
  RSVP
• The message processing times have been estimated
  to be approximately same (1 ms)
• In the IP multiservice backbones some Intserv
  over DiffServ approach, such as RMD, could be the
  solution
• The message processing time in the core routers
  is approximately 5 microsec.
• The system bottleneck is the signaling load on
  the edge routers
• Theres only approximately 0,9 msec time to
  process one reservation message in the edge
  router
• The link utilization is the same than with
  per-flow reservations
• The response time is lower because of the
  sender-oriented approach

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Conclusions (continued)

• NSIS in itself has failed to meet its design
  criteria
• It is not simple and ligthweight -gt It is too
  modular
• There is a serious risk that NSIS will become
  only one signaling protocol amoung others
• Too much politics involved in the protocol design
  work
• The router vendors are not actively participating
  the work -gt the possibility to implement NSIS in
  networks is dependent of the router implementation

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Future research

• Router vendors interests
• NSIS(RMD) / RSVP(RMD) with MPLS-tunnels
• DCCP -gt the adjustment of voice codecs with
  network congestion, ECN marking

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THANK YOU!

• Any questions?

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ADDITIONAL INFORMATION
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Dynamic Provisioning Methods in the Media Gateway

• Measurement Based Admission Control (MBAC)
• CAC is fast
• no extra signaling load
• implementation costs low
• cannot guarantee anything
• the measurement result arrives always too late
• Probing
• no actual traffic will be lost
• additional traffic -gt the probe packets can
  overload the network
• Setup delay
• the routers do not support ?
• Bandwidth Broker (BB)
• high utilization
• - complex new node in the network

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RSVP vs. RMD Performance
RSVP NSIS (RMD)
Response time (bi-directional) 1 1.5 RTT 0.5 1 RTT
Processing time lt 1 ms Edge lt 1ms Int. lt 5 ?s
Link utilization 100 100
Scalability limited yes
Cost High processing capacity is required in each nodes Edge nodes same as for RSVP Int. nodes simple functionality
Source A. Bader et al.Presentation in the 11th
International Telecommunications Network Strategy
and Planning Symposium (Networks2004)