Title: Signaled Provisioning of the IP Network Resources Between the Media Gateways in Mobile Networks
1Signaled Provisioning of the IP Network
Resources Between the Media Gateways in Mobile
Networks
2Problem 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
3Objectives 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.
4The functional architecture of the 3G network
5The Call Admission Control Mechanism
6Provisioning Methods in the IP Multiservice
Backbone
.
.
MBAC Measurement Based Admission Control MPLS
Multiprotocol Label Switching
7Static Provisioning Methods in the Media Gateway
8Signaled 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.
9The NSIS Signaling Framework
NSLP NSIS Signaling Application Level NTLP
NSIS Transport Level
10The 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.
11Comparison 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
12NSIS(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
13Successful Reservation
Receiver
Edge
Initiator
Edge
Interior
Interior
14One Possible Implementation of NSIS to the 3G
15Evaluation
- 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?
16Evaluation 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
17Per-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
18Per-Reservation Performance MetricsSignaling
Bandwidth Overhead
19Per-Reservation Performance MetricsAbortive
Provisioning
20Per-Reservation Performance MetricsBlocking
Probability
21Per-Reservation Performance MetricsReservation
Setup Time
22Conclusions
- 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
23Conclusions (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
24Future research
- Router vendors interests
- NSIS(RMD) / RSVP(RMD) with MPLS-tunnels
- DCCP -gt the adjustment of voice codecs with
network congestion, ECN marking
25THANK YOU!
26ADDITIONAL INFORMATION
27Dynamic 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
28RSVP 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)